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143      <details id="toc" open><summary>Table of contents</summary><ul>
144<li><span class="stability_2"><a href="#http_http">HTTP</a></span>
145<ul>
146<li><a href="#http_class_http_agent">Class: <code>http.Agent</code></a>
147<ul>
148<li><a href="#http_new_agent_options"><code>new Agent([options])</code></a></li>
149<li><a href="#http_agent_createconnection_options_callback"><code>agent.createConnection(options[, callback])</code></a></li>
150<li><a href="#http_agent_keepsocketalive_socket"><code>agent.keepSocketAlive(socket)</code></a></li>
151<li><a href="#http_agent_reusesocket_socket_request"><code>agent.reuseSocket(socket, request)</code></a></li>
152<li><a href="#http_agent_destroy"><code>agent.destroy()</code></a></li>
153<li><a href="#http_agent_freesockets"><code>agent.freeSockets</code></a></li>
154<li><a href="#http_agent_getname_options"><code>agent.getName(options)</code></a></li>
155<li><a href="#http_agent_maxfreesockets"><code>agent.maxFreeSockets</code></a></li>
156<li><a href="#http_agent_maxsockets"><code>agent.maxSockets</code></a></li>
157<li><a href="#http_agent_maxtotalsockets"><code>agent.maxTotalSockets</code></a></li>
158<li><a href="#http_agent_requests"><code>agent.requests</code></a></li>
159<li><a href="#http_agent_sockets"><code>agent.sockets</code></a></li>
160</ul>
161</li>
162<li><a href="#http_class_http_clientrequest">Class: <code>http.ClientRequest</code></a>
163<ul>
164<li><a href="#http_event_abort">Event: <code>'abort'</code></a></li>
165<li><a href="#http_event_connect">Event: <code>'connect'</code></a></li>
166<li><a href="#http_event_continue">Event: <code>'continue'</code></a></li>
167<li><a href="#http_event_information">Event: <code>'information'</code></a></li>
168<li><a href="#http_event_response">Event: <code>'response'</code></a></li>
169<li><a href="#http_event_socket">Event: <code>'socket'</code></a></li>
170<li><a href="#http_event_timeout">Event: <code>'timeout'</code></a></li>
171<li><a href="#http_event_upgrade">Event: <code>'upgrade'</code></a></li>
172<li><span class="stability_0"><a href="#http_request_abort"><code>request.abort()</code></a></span></li>
173<li><a href="#http_request_aborted"><code>request.aborted</code></a></li>
174<li><span class="stability_0"><a href="#http_request_connection"><code>request.connection</code></a></span></li>
175<li><a href="#http_request_end_data_encoding_callback"><code>request.end([data[, encoding]][, callback])</code></a></li>
176<li><a href="#http_request_destroy_error"><code>request.destroy([error])</code></a>
177<ul>
178<li><a href="#http_request_destroyed"><code>request.destroyed</code></a></li>
179</ul>
180</li>
181<li><span class="stability_0"><a href="#http_request_finished"><code>request.finished</code></a></span></li>
182<li><a href="#http_request_flushheaders"><code>request.flushHeaders()</code></a></li>
183<li><a href="#http_request_getheader_name"><code>request.getHeader(name)</code></a></li>
184<li><a href="#http_request_getrawheadernames"><code>request.getRawHeaderNames()</code></a></li>
185<li><a href="#http_request_maxheaderscount"><code>request.maxHeadersCount</code></a></li>
186<li><a href="#http_request_path"><code>request.path</code></a></li>
187<li><a href="#http_request_method"><code>request.method</code></a></li>
188<li><a href="#http_request_host"><code>request.host</code></a></li>
189<li><a href="#http_request_protocol"><code>request.protocol</code></a></li>
190<li><a href="#http_request_removeheader_name"><code>request.removeHeader(name)</code></a></li>
191<li><a href="#http_request_reusedsocket"><code>request.reusedSocket</code></a></li>
192<li><a href="#http_request_setheader_name_value"><code>request.setHeader(name, value)</code></a></li>
193<li><a href="#http_request_setnodelay_nodelay"><code>request.setNoDelay([noDelay])</code></a></li>
194<li><a href="#http_request_setsocketkeepalive_enable_initialdelay"><code>request.setSocketKeepAlive([enable][, initialDelay])</code></a></li>
195<li><a href="#http_request_settimeout_timeout_callback"><code>request.setTimeout(timeout[, callback])</code></a></li>
196<li><a href="#http_request_socket"><code>request.socket</code></a></li>
197<li><a href="#http_request_writableended"><code>request.writableEnded</code></a></li>
198<li><a href="#http_request_writablefinished"><code>request.writableFinished</code></a></li>
199<li><a href="#http_request_write_chunk_encoding_callback"><code>request.write(chunk[, encoding][, callback])</code></a></li>
200</ul>
201</li>
202<li><a href="#http_class_http_server">Class: <code>http.Server</code></a>
203<ul>
204<li><a href="#http_event_checkcontinue">Event: <code>'checkContinue'</code></a></li>
205<li><a href="#http_event_checkexpectation">Event: <code>'checkExpectation'</code></a></li>
206<li><a href="#http_event_clienterror">Event: <code>'clientError'</code></a></li>
207<li><a href="#http_event_close">Event: <code>'close'</code></a></li>
208<li><a href="#http_event_connect_1">Event: <code>'connect'</code></a></li>
209<li><a href="#http_event_connection">Event: <code>'connection'</code></a></li>
210<li><a href="#http_event_request">Event: <code>'request'</code></a></li>
211<li><a href="#http_event_upgrade_1">Event: <code>'upgrade'</code></a></li>
212<li><a href="#http_server_close_callback"><code>server.close([callback])</code></a></li>
213<li><a href="#http_server_headerstimeout"><code>server.headersTimeout</code></a></li>
214<li><a href="#http_server_listen"><code>server.listen()</code></a></li>
215<li><a href="#http_server_listening"><code>server.listening</code></a></li>
216<li><a href="#http_server_maxheaderscount"><code>server.maxHeadersCount</code></a></li>
217<li><a href="#http_server_requesttimeout"><code>server.requestTimeout</code></a></li>
218<li><a href="#http_server_settimeout_msecs_callback"><code>server.setTimeout([msecs][, callback])</code></a></li>
219<li><a href="#http_server_timeout"><code>server.timeout</code></a></li>
220<li><a href="#http_server_keepalivetimeout"><code>server.keepAliveTimeout</code></a></li>
221</ul>
222</li>
223<li><a href="#http_class_http_serverresponse">Class: <code>http.ServerResponse</code></a>
224<ul>
225<li><a href="#http_event_close_1">Event: <code>'close'</code></a></li>
226<li><a href="#http_event_finish">Event: <code>'finish'</code></a></li>
227<li><a href="#http_response_addtrailers_headers"><code>response.addTrailers(headers)</code></a></li>
228<li><span class="stability_0"><a href="#http_response_connection"><code>response.connection</code></a></span></li>
229<li><a href="#http_response_cork"><code>response.cork()</code></a></li>
230<li><a href="#http_response_end_data_encoding_callback"><code>response.end([data[, encoding]][, callback])</code></a></li>
231<li><span class="stability_0"><a href="#http_response_finished"><code>response.finished</code></a></span></li>
232<li><a href="#http_response_flushheaders"><code>response.flushHeaders()</code></a></li>
233<li><a href="#http_response_getheader_name"><code>response.getHeader(name)</code></a></li>
234<li><a href="#http_response_getheadernames"><code>response.getHeaderNames()</code></a></li>
235<li><a href="#http_response_getheaders"><code>response.getHeaders()</code></a></li>
236<li><a href="#http_response_hasheader_name"><code>response.hasHeader(name)</code></a></li>
237<li><a href="#http_response_headerssent"><code>response.headersSent</code></a></li>
238<li><a href="#http_response_removeheader_name"><code>response.removeHeader(name)</code></a></li>
239<li><a href="#http_response_senddate"><code>response.sendDate</code></a></li>
240<li><a href="#http_response_setheader_name_value"><code>response.setHeader(name, value)</code></a></li>
241<li><a href="#http_response_settimeout_msecs_callback"><code>response.setTimeout(msecs[, callback])</code></a></li>
242<li><a href="#http_response_socket"><code>response.socket</code></a></li>
243<li><a href="#http_response_statuscode"><code>response.statusCode</code></a></li>
244<li><a href="#http_response_statusmessage"><code>response.statusMessage</code></a></li>
245<li><a href="#http_response_uncork"><code>response.uncork()</code></a></li>
246<li><a href="#http_response_writableended"><code>response.writableEnded</code></a></li>
247<li><a href="#http_response_writablefinished"><code>response.writableFinished</code></a></li>
248<li><a href="#http_response_write_chunk_encoding_callback"><code>response.write(chunk[, encoding][, callback])</code></a></li>
249<li><a href="#http_response_writecontinue"><code>response.writeContinue()</code></a></li>
250<li><a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead(statusCode[, statusMessage][, headers])</code></a></li>
251<li><a href="#http_response_writeprocessing"><code>response.writeProcessing()</code></a></li>
252</ul>
253</li>
254<li><a href="#http_class_http_incomingmessage">Class: <code>http.IncomingMessage</code></a>
255<ul>
256<li><a href="#http_event_aborted">Event: <code>'aborted'</code></a></li>
257<li><a href="#http_event_close_2">Event: <code>'close'</code></a></li>
258<li><a href="#http_message_aborted"><code>message.aborted</code></a></li>
259<li><a href="#http_message_complete"><code>message.complete</code></a></li>
260<li><a href="#http_message_destroy_error"><code>message.destroy([error])</code></a></li>
261<li><a href="#http_message_headers"><code>message.headers</code></a></li>
262<li><a href="#http_message_httpversion"><code>message.httpVersion</code></a></li>
263<li><a href="#http_message_method"><code>message.method</code></a></li>
264<li><a href="#http_message_rawheaders"><code>message.rawHeaders</code></a></li>
265<li><a href="#http_message_rawtrailers"><code>message.rawTrailers</code></a></li>
266<li><a href="#http_message_settimeout_msecs_callback"><code>message.setTimeout(msecs[, callback])</code></a></li>
267<li><a href="#http_message_socket"><code>message.socket</code></a></li>
268<li><a href="#http_message_statuscode"><code>message.statusCode</code></a></li>
269<li><a href="#http_message_statusmessage"><code>message.statusMessage</code></a></li>
270<li><a href="#http_message_trailers"><code>message.trailers</code></a></li>
271<li><a href="#http_message_url"><code>message.url</code></a></li>
272</ul>
273</li>
274<li><a href="#http_class_http_outgoingmessage">Class: <code>http.OutgoingMessage</code></a>
275<ul>
276<li><a href="#http_event_drain">Event: <code>drain</code></a></li>
277<li><a href="#http_event_finish_1">Event: <code>finish</code></a></li>
278<li><a href="#http_event_prefinish">Event: <code>prefinish</code></a></li>
279<li><a href="#http_outgoingmessage_addtrailers_headers"><code>outgoingMessage.addTrailers(headers)</code></a></li>
280<li><span class="stability_0"><a href="#http_outgoingmessage_connection"><code>outgoingMessage.connection</code></a></span></li>
281<li><a href="#http_outgoingmessage_cork"><code>outgoingMessage.cork()</code></a></li>
282<li><a href="#http_outgoingmessage_destroy_error"><code>outgoingMessage.destroy([error])</code></a></li>
283<li><a href="#http_outgoingmessage_end_chunk_encoding_callback"><code>outgoingMessage.end(chunk[, encoding][, callback])</code></a></li>
284<li><a href="#http_outgoingmessage_flushheaders"><code>outgoingMessage.flushHeaders()</code></a></li>
285<li><a href="#http_outgoingmessage_getheader_name"><code>outgoingMessage.getHeader(name)</code></a></li>
286<li><a href="#http_outgoingmessage_getheadernames"><code>outgoingMessage.getHeaderNames()</code></a></li>
287<li><a href="#http_outgoingmessage_getheaders"><code>outgoingMessage.getHeaders()</code></a></li>
288<li><a href="#http_outgoingmessage_hasheader_name"><code>outgoingMessage.hasHeader(name)</code></a></li>
289<li><a href="#http_outgoingmessage_headerssent"><code>outgoingMessage.headersSent</code></a></li>
290<li><a href="#http_outgoingmessage_pipe"><code>outgoingMessage.pipe()</code></a></li>
291<li><a href="#http_outgoingmessage_removeheader"><code>outgoingMessage.removeHeader()</code></a></li>
292<li><a href="#http_outgoingmessage_setheader_name_value"><code>outgoingMessage.setHeader(name, value)</code></a></li>
293<li><a href="#http_outgoingmessage_settimeout_msesc_callback"><code>outgoingMessage.setTimeout(msesc[, callback])</code></a></li>
294<li><a href="#http_outgoingmessage_socket"><code>outgoingMessage.socket</code></a></li>
295<li><a href="#http_outgoingmessage_uncork"><code>outgoingMessage.uncork()</code></a></li>
296<li><a href="#http_outgoingmessage_writablecorked"><code>outgoingMessage.writableCorked</code></a></li>
297<li><a href="#http_outgoingmessage_writableended"><code>outgoingMessage.writableEnded</code></a></li>
298<li><a href="#http_outgoingmessage_writablefinished"><code>outgoingMessage.writableFinished</code></a></li>
299<li><a href="#http_outgoingmessage_writablehighwatermark"><code>outgoingMessage.writableHighWaterMark</code></a></li>
300<li><a href="#http_outgoingmessage_writablelength"><code>outgoingMessage.writableLength</code></a></li>
301<li><a href="#http_outgoingmessage_writableobjectmode"><code>outgoingMessage.writableObjectMode</code></a></li>
302<li><a href="#http_outgoingmessage_write_chunk_encoding_callback"><code>outgoingMessage.write(chunk[, encoding][, callback])</code></a></li>
303</ul>
304</li>
305<li><a href="#http_http_methods"><code>http.METHODS</code></a></li>
306<li><a href="#http_http_status_codes"><code>http.STATUS_CODES</code></a></li>
307<li><a href="#http_http_createserver_options_requestlistener"><code>http.createServer([options][, requestListener])</code></a></li>
308<li><a href="#http_http_get_options_callback"><code>http.get(options[, callback])</code></a></li>
309<li><a href="#http_http_get_url_options_callback"><code>http.get(url[, options][, callback])</code></a></li>
310<li><a href="#http_http_globalagent"><code>http.globalAgent</code></a></li>
311<li><a href="#http_http_maxheadersize"><code>http.maxHeaderSize</code></a></li>
312<li><a href="#http_http_request_options_callback"><code>http.request(options[, callback])</code></a></li>
313<li><a href="#http_http_request_url_options_callback"><code>http.request(url[, options][, callback])</code></a></li>
314<li><a href="#http_http_validateheadername_name"><code>http.validateHeaderName(name)</code></a></li>
315<li><a href="#http_http_validateheadervalue_name_value"><code>http.validateHeaderValue(name, value)</code></a></li>
316</ul>
317</li>
318</ul></details>
319
320      <div id="apicontent">
321        <h2>HTTP<span><a class="mark" href="#http_http" id="http_http">#</a></span></h2>
322
323<p></p><div class="api_stability api_stability_2"><a href="documentation.html#documentation_stability_index">Stability: 2</a> - Stable</div><p></p>
324<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v14.19.1/lib/http.js">lib/http.js</a></p>
325<p>To use the HTTP server and client one must <code>require('http')</code>.</p>
326<p>The HTTP interfaces in Node.js are designed to support many features
327of the protocol which have been traditionally difficult to use.
328In particular, large, possibly chunk-encoded, messages. The interface is
329careful to never buffer entire requests or responses, so the
330user is able to stream data.</p>
331<p>HTTP message headers are represented by an object like this:</p>
332<!-- eslint-skip -->
333<pre><code class="language-js">{ <span class="hljs-string">'content-length'</span>: <span class="hljs-string">'123'</span>,
334  <span class="hljs-string">'content-type'</span>: <span class="hljs-string">'text/plain'</span>,
335  <span class="hljs-string">'connection'</span>: <span class="hljs-string">'keep-alive'</span>,
336  <span class="hljs-string">'host'</span>: <span class="hljs-string">'mysite.com'</span>,
337  <span class="hljs-string">'accept'</span>: <span class="hljs-string">'*/*'</span> }</code></pre>
338<p>Keys are lowercased. Values are not modified.</p>
339<p>In order to support the full spectrum of possible HTTP applications, the Node.js
340HTTP API is very low-level. It deals with stream handling and message
341parsing only. It parses a message into headers and body but it does not
342parse the actual headers or the body.</p>
343<p>See <a href="#http_message_headers"><code>message.headers</code></a> for details on how duplicate headers are handled.</p>
344<p>The raw headers as they were received are retained in the <code>rawHeaders</code>
345property, which is an array of <code>[key, value, key2, value2, ...]</code>. For
346example, the previous message header object might have a <code>rawHeaders</code>
347list like the following:</p>
348<!-- eslint-disable semi -->
349<pre><code class="language-js">[ <span class="hljs-string">'ConTent-Length'</span>, <span class="hljs-string">'123456'</span>,
350  <span class="hljs-string">'content-LENGTH'</span>, <span class="hljs-string">'123'</span>,
351  <span class="hljs-string">'content-type'</span>, <span class="hljs-string">'text/plain'</span>,
352  <span class="hljs-string">'CONNECTION'</span>, <span class="hljs-string">'keep-alive'</span>,
353  <span class="hljs-string">'Host'</span>, <span class="hljs-string">'mysite.com'</span>,
354  <span class="hljs-string">'accepT'</span>, <span class="hljs-string">'*/*'</span> ]</code></pre>
355<section><h3>Class: <code>http.Agent</code><span><a class="mark" href="#http_class_http_agent" id="http_class_http_agent">#</a></span></h3>
356<div class="api_metadata">
357<span>Added in: v0.3.4</span>
358</div>
359<p>An <code>Agent</code> is responsible for managing connection persistence
360and reuse for HTTP clients. It maintains a queue of pending requests
361for a given host and port, reusing a single socket connection for each
362until the queue is empty, at which time the socket is either destroyed
363or put into a pool where it is kept to be used again for requests to the
364same host and port. Whether it is destroyed or pooled depends on the
365<code>keepAlive</code> <a href="#http_new_agent_options">option</a>.</p>
366<p>Pooled connections have TCP Keep-Alive enabled for them, but servers may
367still close idle connections, in which case they will be removed from the
368pool and a new connection will be made when a new HTTP request is made for
369that host and port. Servers may also refuse to allow multiple requests
370over the same connection, in which case the connection will have to be
371remade for every request and cannot be pooled. The <code>Agent</code> will still make
372the requests to that server, but each one will occur over a new connection.</p>
373<p>When a connection is closed by the client or the server, it is removed
374from the pool. Any unused sockets in the pool will be unrefed so as not
375to keep the Node.js process running when there are no outstanding requests.
376(see <a href="net.html#net_socket_unref"><code>socket.unref()</code></a>).</p>
377<p>It is good practice, to <a href="#http_agent_destroy"><code>destroy()</code></a> an <code>Agent</code> instance when it is no
378longer in use, because unused sockets consume OS resources.</p>
379<p>Sockets are removed from an agent when the socket emits either
380a <code>'close'</code> event or an <code>'agentRemove'</code> event. When intending to keep one
381HTTP request open for a long time without keeping it in the agent, something
382like the following may be done:</p>
383<pre><code class="language-js">http.<span class="hljs-title function_">get</span>(options, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
384  <span class="hljs-comment">// Do stuff</span>
385}).<span class="hljs-title function_">on</span>(<span class="hljs-string">'socket'</span>, <span class="hljs-function">(<span class="hljs-params">socket</span>) =></span> {
386  socket.<span class="hljs-title function_">emit</span>(<span class="hljs-string">'agentRemove'</span>);
387});</code></pre>
388<p>An agent may also be used for an individual request. By providing
389<code>{agent: false}</code> as an option to the <code>http.get()</code> or <code>http.request()</code>
390functions, a one-time use <code>Agent</code> with default options will be used
391for the client connection.</p>
392<p><code>agent:false</code>:</p>
393<pre><code class="language-js">http.<span class="hljs-title function_">get</span>({
394  <span class="hljs-attr">hostname</span>: <span class="hljs-string">'localhost'</span>,
395  <span class="hljs-attr">port</span>: <span class="hljs-number">80</span>,
396  <span class="hljs-attr">path</span>: <span class="hljs-string">'/'</span>,
397  <span class="hljs-attr">agent</span>: <span class="hljs-literal">false</span>  <span class="hljs-comment">// Create a new agent just for this one request</span>
398}, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
399  <span class="hljs-comment">// Do stuff with response</span>
400});</code></pre>
401<h4><code>new Agent([options])</code><span><a class="mark" href="#http_new_agent_options" id="http_new_agent_options">#</a></span></h4>
402<div class="api_metadata">
403<details class="changelog"><summary>History</summary>
404<table>
405<tbody><tr><th>Version</th><th>Changes</th></tr>
406<tr><td>v14.17.0</td>
407<td><p>Change the default scheduling from 'fifo' to 'lifo'.</p></td></tr>
408<tr><td>v14.5.0</td>
409<td><p>Add <code>maxTotalSockets</code> option to agent constructor.</p></td></tr>
410<tr><td>v14.5.0</td>
411<td><p>Add <code>scheduling</code> option to specify the free socket scheduling strategy.</p></td></tr>
412<tr><td>v0.3.4</td>
413<td><p><span>Added in: v0.3.4</span></p></td></tr>
414</tbody></table>
415</details>
416</div>
417<ul>
418<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> Set of configurable options to set on the agent.
419Can have the following fields:
420<ul>
421<li><code>keepAlive</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Keep sockets around even when there are no
422outstanding requests, so they can be used for future requests without
423having to reestablish a TCP connection. Not to be confused with the
424<code>keep-alive</code> value of the <code>Connection</code> header. The <code>Connection: keep-alive</code>
425header is always sent when using an agent except when the <code>Connection</code>
426header is explicitly specified or when the <code>keepAlive</code> and <code>maxSockets</code>
427options are respectively set to <code>false</code> and <code>Infinity</code>, in which case
428<code>Connection: close</code> will be used. <strong>Default:</strong> <code>false</code>.</li>
429<li><code>keepAliveMsecs</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> When using the <code>keepAlive</code> option, specifies
430the <a href="net.html#net_socket_setkeepalive_enable_initialdelay">initial delay</a>
431for TCP Keep-Alive packets. Ignored when the
432<code>keepAlive</code> option is <code>false</code> or <code>undefined</code>. <strong>Default:</strong> <code>1000</code>.</li>
433<li><code>maxSockets</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Maximum number of sockets to allow per host.
434If the same host opens multiple concurrent connections, each request
435will use new socket until the <code>maxSockets</code> value is reached.
436If the host attempts to open more connections than <code>maxSockets</code>,
437the additional requests will enter into a pending request queue, and
438will enter active connection state when an existing connection terminates.
439This makes sure there are at most <code>maxSockets</code> active connections at
440any point in time, from a given host.
441<strong>Default:</strong> <code>Infinity</code>.</li>
442<li><code>maxTotalSockets</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Maximum number of sockets allowed for
443all hosts in total. Each request will use a new socket
444until the maximum is reached.
445<strong>Default:</strong> <code>Infinity</code>.</li>
446<li><code>maxFreeSockets</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Maximum number of sockets to leave open
447in a free state. Only relevant if <code>keepAlive</code> is set to <code>true</code>.
448<strong>Default:</strong> <code>256</code>.</li>
449<li><code>scheduling</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Scheduling strategy to apply when picking
450the next free socket to use. It can be <code>'fifo'</code> or <code>'lifo'</code>.
451The main difference between the two scheduling strategies is that <code>'lifo'</code>
452selects the most recently used socket, while <code>'fifo'</code> selects
453the least recently used socket.
454In case of a low rate of request per second, the <code>'lifo'</code> scheduling
455will lower the risk of picking a socket that might have been closed
456by the server due to inactivity.
457In case of a high rate of request per second,
458the <code>'fifo'</code> scheduling will maximize the number of open sockets,
459while the <code>'lifo'</code> scheduling will keep it as low as possible.
460<strong>Default:</strong> <code>'lifo'</code>.</li>
461<li><code>timeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Socket timeout in milliseconds.
462This will set the timeout when the socket is created.</li>
463</ul>
464</li>
465</ul>
466<p><code>options</code> in <a href="net.html#net_socket_connect_options_connectlistener"><code>socket.connect()</code></a> are also supported.</p>
467<p>The default <a href="#http_http_globalagent"><code>http.globalAgent</code></a> that is used by <a href="#http_http_request_options_callback"><code>http.request()</code></a> has all
468of these values set to their respective defaults.</p>
469<p>To configure any of them, a custom <a href="#http_class_http_agent"><code>http.Agent</code></a> instance must be created.</p>
470<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
471<span class="hljs-keyword">const</span> keepAliveAgent = <span class="hljs-keyword">new</span> http.<span class="hljs-title class_">Agent</span>({ <span class="hljs-attr">keepAlive</span>: <span class="hljs-literal">true</span> });
472options.<span class="hljs-property">agent</span> = keepAliveAgent;
473http.<span class="hljs-title function_">request</span>(options, onResponseCallback);</code></pre>
474<h4><code>agent.createConnection(options[, callback])</code><span><a class="mark" href="#http_agent_createconnection_options_callback" id="http_agent_createconnection_options_callback">#</a></span></h4>
475<div class="api_metadata">
476<span>Added in: v0.11.4</span>
477</div>
478<ul>
479<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> Options containing connection details. Check
480<a href="net.html#net_net_createconnection_options_connectlistener"><code>net.createConnection()</code></a> for the format of the options</li>
481<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Callback function that receives the created socket</li>
482<li>Returns: <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
483</ul>
484<p>Produces a socket/stream to be used for HTTP requests.</p>
485<p>By default, this function is the same as <a href="net.html#net_net_createconnection_options_connectlistener"><code>net.createConnection()</code></a>. However,
486custom agents may override this method in case greater flexibility is desired.</p>
487<p>A socket/stream can be supplied in one of two ways: by returning the
488socket/stream from this function, or by passing the socket/stream to <code>callback</code>.</p>
489<p>This method is guaranteed to return an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
490a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
491type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
492<p><code>callback</code> has a signature of <code>(err, stream)</code>.</p>
493<h4><code>agent.keepSocketAlive(socket)</code><span><a class="mark" href="#http_agent_keepsocketalive_socket" id="http_agent_keepsocketalive_socket">#</a></span></h4>
494<div class="api_metadata">
495<span>Added in: v8.1.0</span>
496</div>
497<ul>
498<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
499</ul>
500<p>Called when <code>socket</code> is detached from a request and could be persisted by the
501<code>Agent</code>. Default behavior is to:</p>
502<pre><code class="language-js">socket.<span class="hljs-title function_">setKeepAlive</span>(<span class="hljs-literal">true</span>, <span class="hljs-variable language_">this</span>.<span class="hljs-property">keepAliveMsecs</span>);
503socket.<span class="hljs-title function_">unref</span>();
504<span class="hljs-keyword">return</span> <span class="hljs-literal">true</span>;</code></pre>
505<p>This method can be overridden by a particular <code>Agent</code> subclass. If this
506method returns a falsy value, the socket will be destroyed instead of persisting
507it for use with the next request.</p>
508<p>The <code>socket</code> argument can be an instance of <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>, a subclass of
509<a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>.</p>
510<h4><code>agent.reuseSocket(socket, request)</code><span><a class="mark" href="#http_agent_reusesocket_socket_request" id="http_agent_reusesocket_socket_request">#</a></span></h4>
511<div class="api_metadata">
512<span>Added in: v8.1.0</span>
513</div>
514<ul>
515<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
516<li><code>request</code> <a href="http.html#http_class_http_clientrequest" class="type">&#x3C;http.ClientRequest></a></li>
517</ul>
518<p>Called when <code>socket</code> is attached to <code>request</code> after being persisted because of
519the keep-alive options. Default behavior is to:</p>
520<pre><code class="language-js">socket.<span class="hljs-title function_">ref</span>();</code></pre>
521<p>This method can be overridden by a particular <code>Agent</code> subclass.</p>
522<p>The <code>socket</code> argument can be an instance of <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>, a subclass of
523<a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>.</p>
524<h4><code>agent.destroy()</code><span><a class="mark" href="#http_agent_destroy" id="http_agent_destroy">#</a></span></h4>
525<div class="api_metadata">
526<span>Added in: v0.11.4</span>
527</div>
528<p>Destroy any sockets that are currently in use by the agent.</p>
529<p>It is usually not necessary to do this. However, if using an
530agent with <code>keepAlive</code> enabled, then it is best to explicitly shut down
531the agent when it is no longer needed. Otherwise,
532sockets might stay open for quite a long time before the server
533terminates them.</p>
534<h4><code>agent.freeSockets</code><span><a class="mark" href="#http_agent_freesockets" id="http_agent_freesockets">#</a></span></h4>
535<div class="api_metadata">
536<span>Added in: v0.11.4</span>
537</div>
538<ul>
539<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
540</ul>
541<p>An object which contains arrays of sockets currently awaiting use by
542the agent when <code>keepAlive</code> is enabled. Do not modify.</p>
543<p>Sockets in the <code>freeSockets</code> list will be automatically destroyed and
544removed from the array on <code>'timeout'</code>.</p>
545<h4><code>agent.getName(options)</code><span><a class="mark" href="#http_agent_getname_options" id="http_agent_getname_options">#</a></span></h4>
546<div class="api_metadata">
547<span>Added in: v0.11.4</span>
548</div>
549<ul>
550<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> A set of options providing information for name generation
551<ul>
552<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> A domain name or IP address of the server to issue the
553request to</li>
554<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Port of remote server</li>
555<li><code>localAddress</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Local interface to bind for network connections
556when issuing the request</li>
557<li><code>family</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;integer></a> Must be 4 or 6 if this doesn't equal <code>undefined</code>.</li>
558</ul>
559</li>
560<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
561</ul>
562<p>Get a unique name for a set of request options, to determine whether a
563connection can be reused. For an HTTP agent, this returns
564<code>host:port:localAddress</code> or <code>host:port:localAddress:family</code>. For an HTTPS agent,
565the name includes the CA, cert, ciphers, and other HTTPS/TLS-specific options
566that determine socket reusability.</p>
567<h4><code>agent.maxFreeSockets</code><span><a class="mark" href="#http_agent_maxfreesockets" id="http_agent_maxfreesockets">#</a></span></h4>
568<div class="api_metadata">
569<span>Added in: v0.11.7</span>
570</div>
571<ul>
572<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
573</ul>
574<p>By default set to 256. For agents with <code>keepAlive</code> enabled, this
575sets the maximum number of sockets that will be left open in the free
576state.</p>
577<h4><code>agent.maxSockets</code><span><a class="mark" href="#http_agent_maxsockets" id="http_agent_maxsockets">#</a></span></h4>
578<div class="api_metadata">
579<span>Added in: v0.3.6</span>
580</div>
581<ul>
582<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
583</ul>
584<p>By default set to <code>Infinity</code>. Determines how many concurrent sockets the agent
585can have open per origin. Origin is the returned value of <a href="#http_agent_getname_options"><code>agent.getName()</code></a>.</p>
586<h4><code>agent.maxTotalSockets</code><span><a class="mark" href="#http_agent_maxtotalsockets" id="http_agent_maxtotalsockets">#</a></span></h4>
587<div class="api_metadata">
588<span>Added in: v14.5.0</span>
589</div>
590<ul>
591<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
592</ul>
593<p>By default set to <code>Infinity</code>. Determines how many concurrent sockets the agent
594can have open. Unlike <code>maxSockets</code>, this parameter applies across all origins.</p>
595<h4><code>agent.requests</code><span><a class="mark" href="#http_agent_requests" id="http_agent_requests">#</a></span></h4>
596<div class="api_metadata">
597<span>Added in: v0.5.9</span>
598</div>
599<ul>
600<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
601</ul>
602<p>An object which contains queues of requests that have not yet been assigned to
603sockets. Do not modify.</p>
604<h4><code>agent.sockets</code><span><a class="mark" href="#http_agent_sockets" id="http_agent_sockets">#</a></span></h4>
605<div class="api_metadata">
606<span>Added in: v0.3.6</span>
607</div>
608<ul>
609<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
610</ul>
611<p>An object which contains arrays of sockets currently in use by the
612agent. Do not modify.</p>
613</section><section><h3>Class: <code>http.ClientRequest</code><span><a class="mark" href="#http_class_http_clientrequest" id="http_class_http_clientrequest">#</a></span></h3>
614<div class="api_metadata">
615<span>Added in: v0.1.17</span>
616</div>
617<ul>
618<li>Extends: <a href="stream.html#stream_stream" class="type">&#x3C;Stream></a></li>
619</ul>
620<p>This object is created internally and returned from <a href="#http_http_request_options_callback"><code>http.request()</code></a>. It
621represents an <em>in-progress</em> request whose header has already been queued. The
622header is still mutable using the <a href="#http_request_setheader_name_value"><code>setHeader(name, value)</code></a>,
623<a href="#http_request_getheader_name"><code>getHeader(name)</code></a>, <a href="#http_request_removeheader_name"><code>removeHeader(name)</code></a> API. The actual header will
624be sent along with the first data chunk or when calling <a href="#http_request_end_data_encoding_callback"><code>request.end()</code></a>.</p>
625<p>To get the response, add a listener for <a href="#http_event_response"><code>'response'</code></a> to the request object.
626<a href="#http_event_response"><code>'response'</code></a> will be emitted from the request object when the response
627headers have been received. The <a href="#http_event_response"><code>'response'</code></a> event is executed with one
628argument which is an instance of <a href="#http_class_http_incomingmessage"><code>http.IncomingMessage</code></a>.</p>
629<p>During the <a href="#http_event_response"><code>'response'</code></a> event, one can add listeners to the
630response object; particularly to listen for the <code>'data'</code> event.</p>
631<p>If no <a href="#http_event_response"><code>'response'</code></a> handler is added, then the response will be
632entirely discarded. However, if a <a href="#http_event_response"><code>'response'</code></a> event handler is added,
633then the data from the response object <strong>must</strong> be consumed, either by
634calling <code>response.read()</code> whenever there is a <code>'readable'</code> event, or
635by adding a <code>'data'</code> handler, or by calling the <code>.resume()</code> method.
636Until the data is consumed, the <code>'end'</code> event will not fire. Also, until
637the data is read it will consume memory that can eventually lead to a
638'process out of memory' error.</p>
639<p>Unlike the <code>request</code> object, if the response closes prematurely, the
640<code>response</code> object does not emit an <code>'error'</code> event but instead emits the
641<code>'aborted'</code> event.</p>
642<p>Node.js does not check whether Content-Length and the length of the
643body which has been transmitted are equal or not.</p>
644<h4>Event: <code>'abort'</code><span><a class="mark" href="#http_event_abort" id="http_event_abort">#</a></span></h4>
645<div class="api_metadata">
646<span>Added in: v1.4.1</span>
647</div>
648<p>Emitted when the request has been aborted by the client. This event is only
649emitted on the first call to <code>abort()</code>.</p>
650<h4>Event: <code>'connect'</code><span><a class="mark" href="#http_event_connect" id="http_event_connect">#</a></span></h4>
651<div class="api_metadata">
652<span>Added in: v0.7.0</span>
653</div>
654<ul>
655<li><code>response</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a></li>
656<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
657<li><code>head</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
658</ul>
659<p>Emitted each time a server responds to a request with a <code>CONNECT</code> method. If
660this event is not being listened for, clients receiving a <code>CONNECT</code> method will
661have their connections closed.</p>
662<p>This event is guaranteed to be passed an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
663a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
664type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
665<p>A client and server pair demonstrating how to listen for the <code>'connect'</code> event:</p>
666<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
667<span class="hljs-keyword">const</span> net = <span class="hljs-built_in">require</span>(<span class="hljs-string">'net'</span>);
668<span class="hljs-keyword">const</span> { <span class="hljs-variable constant_">URL</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'url'</span>);
669
670<span class="hljs-comment">// Create an HTTP tunneling proxy</span>
671<span class="hljs-keyword">const</span> proxy = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
672  res.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'text/plain'</span> });
673  res.<span class="hljs-title function_">end</span>(<span class="hljs-string">'okay'</span>);
674});
675proxy.<span class="hljs-title function_">on</span>(<span class="hljs-string">'connect'</span>, <span class="hljs-function">(<span class="hljs-params">req, clientSocket, head</span>) =></span> {
676  <span class="hljs-comment">// Connect to an origin server</span>
677  <span class="hljs-keyword">const</span> { port, hostname } = <span class="hljs-keyword">new</span> <span class="hljs-title function_">URL</span>(<span class="hljs-string">`http://<span class="hljs-subst">${req.url}</span>`</span>);
678  <span class="hljs-keyword">const</span> serverSocket = net.<span class="hljs-title function_">connect</span>(port || <span class="hljs-number">80</span>, hostname, <span class="hljs-function">() =></span> {
679    clientSocket.<span class="hljs-title function_">write</span>(<span class="hljs-string">'HTTP/1.1 200 Connection Established\r\n'</span> +
680                    <span class="hljs-string">'Proxy-agent: Node.js-Proxy\r\n'</span> +
681                    <span class="hljs-string">'\r\n'</span>);
682    serverSocket.<span class="hljs-title function_">write</span>(head);
683    serverSocket.<span class="hljs-title function_">pipe</span>(clientSocket);
684    clientSocket.<span class="hljs-title function_">pipe</span>(serverSocket);
685  });
686});
687
688<span class="hljs-comment">// Now that proxy is running</span>
689proxy.<span class="hljs-title function_">listen</span>(<span class="hljs-number">1337</span>, <span class="hljs-string">'127.0.0.1'</span>, <span class="hljs-function">() =></span> {
690
691  <span class="hljs-comment">// Make a request to a tunneling proxy</span>
692  <span class="hljs-keyword">const</span> options = {
693    <span class="hljs-attr">port</span>: <span class="hljs-number">1337</span>,
694    <span class="hljs-attr">host</span>: <span class="hljs-string">'127.0.0.1'</span>,
695    <span class="hljs-attr">method</span>: <span class="hljs-string">'CONNECT'</span>,
696    <span class="hljs-attr">path</span>: <span class="hljs-string">'www.google.com:80'</span>
697  };
698
699  <span class="hljs-keyword">const</span> req = http.<span class="hljs-title function_">request</span>(options);
700  req.<span class="hljs-title function_">end</span>();
701
702  req.<span class="hljs-title function_">on</span>(<span class="hljs-string">'connect'</span>, <span class="hljs-function">(<span class="hljs-params">res, socket, head</span>) =></span> {
703    <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'got connected!'</span>);
704
705    <span class="hljs-comment">// Make a request over an HTTP tunnel</span>
706    socket.<span class="hljs-title function_">write</span>(<span class="hljs-string">'GET / HTTP/1.1\r\n'</span> +
707                 <span class="hljs-string">'Host: www.google.com:80\r\n'</span> +
708                 <span class="hljs-string">'Connection: close\r\n'</span> +
709                 <span class="hljs-string">'\r\n'</span>);
710    socket.<span class="hljs-title function_">on</span>(<span class="hljs-string">'data'</span>, <span class="hljs-function">(<span class="hljs-params">chunk</span>) =></span> {
711      <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(chunk.<span class="hljs-title function_">toString</span>());
712    });
713    socket.<span class="hljs-title function_">on</span>(<span class="hljs-string">'end'</span>, <span class="hljs-function">() =></span> {
714      proxy.<span class="hljs-title function_">close</span>();
715    });
716  });
717});</code></pre>
718<h4>Event: <code>'continue'</code><span><a class="mark" href="#http_event_continue" id="http_event_continue">#</a></span></h4>
719<div class="api_metadata">
720<span>Added in: v0.3.2</span>
721</div>
722<p>Emitted when the server sends a '100 Continue' HTTP response, usually because
723the request contained 'Expect: 100-continue'. This is an instruction that
724the client should send the request body.</p>
725<h4>Event: <code>'information'</code><span><a class="mark" href="#http_event_information" id="http_event_information">#</a></span></h4>
726<div class="api_metadata">
727<span>Added in: v10.0.0</span>
728</div>
729<ul>
730<li><code>info</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a>
731<ul>
732<li><code>httpVersion</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
733<li><code>httpVersionMajor</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;integer></a></li>
734<li><code>httpVersionMinor</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;integer></a></li>
735<li><code>statusCode</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;integer></a></li>
736<li><code>statusMessage</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
737<li><code>headers</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
738<li><code>rawHeaders</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
739</ul>
740</li>
741</ul>
742<p>Emitted when the server sends a 1xx intermediate response (excluding 101
743Upgrade). The listeners of this event will receive an object containing the
744HTTP version, status code, status message, key-value headers object,
745and array with the raw header names followed by their respective values.</p>
746<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
747
748<span class="hljs-keyword">const</span> options = {
749  <span class="hljs-attr">host</span>: <span class="hljs-string">'127.0.0.1'</span>,
750  <span class="hljs-attr">port</span>: <span class="hljs-number">8080</span>,
751  <span class="hljs-attr">path</span>: <span class="hljs-string">'/length_request'</span>
752};
753
754<span class="hljs-comment">// Make a request</span>
755<span class="hljs-keyword">const</span> req = http.<span class="hljs-title function_">request</span>(options);
756req.<span class="hljs-title function_">end</span>();
757
758req.<span class="hljs-title function_">on</span>(<span class="hljs-string">'information'</span>, <span class="hljs-function">(<span class="hljs-params">info</span>) =></span> {
759  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`Got information prior to main response: <span class="hljs-subst">${info.statusCode}</span>`</span>);
760});</code></pre>
761<p>101 Upgrade statuses do not fire this event due to their break from the
762traditional HTTP request/response chain, such as web sockets, in-place TLS
763upgrades, or HTTP 2.0. To be notified of 101 Upgrade notices, listen for the
764<a href="#http_event_upgrade"><code>'upgrade'</code></a> event instead.</p>
765<h4>Event: <code>'response'</code><span><a class="mark" href="#http_event_response" id="http_event_response">#</a></span></h4>
766<div class="api_metadata">
767<span>Added in: v0.1.0</span>
768</div>
769<ul>
770<li><code>response</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a></li>
771</ul>
772<p>Emitted when a response is received to this request. This event is emitted only
773once.</p>
774<h4>Event: <code>'socket'</code><span><a class="mark" href="#http_event_socket" id="http_event_socket">#</a></span></h4>
775<div class="api_metadata">
776<span>Added in: v0.5.3</span>
777</div>
778<ul>
779<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
780</ul>
781<p>This event is guaranteed to be passed an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
782a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
783type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
784<h4>Event: <code>'timeout'</code><span><a class="mark" href="#http_event_timeout" id="http_event_timeout">#</a></span></h4>
785<div class="api_metadata">
786<span>Added in: v0.7.8</span>
787</div>
788<p>Emitted when the underlying socket times out from inactivity. This only notifies
789that the socket has been idle. The request must be aborted manually.</p>
790<p>See also: <a href="#http_request_settimeout_timeout_callback"><code>request.setTimeout()</code></a>.</p>
791<h4>Event: <code>'upgrade'</code><span><a class="mark" href="#http_event_upgrade" id="http_event_upgrade">#</a></span></h4>
792<div class="api_metadata">
793<span>Added in: v0.1.94</span>
794</div>
795<ul>
796<li><code>response</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a></li>
797<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
798<li><code>head</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
799</ul>
800<p>Emitted each time a server responds to a request with an upgrade. If this
801event is not being listened for and the response status code is 101 Switching
802Protocols, clients receiving an upgrade header will have their connections
803closed.</p>
804<p>This event is guaranteed to be passed an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
805a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
806type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
807<p>A client server pair demonstrating how to listen for the <code>'upgrade'</code> event.</p>
808<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
809
810<span class="hljs-comment">// Create an HTTP server</span>
811<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
812  res.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'text/plain'</span> });
813  res.<span class="hljs-title function_">end</span>(<span class="hljs-string">'okay'</span>);
814});
815server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'upgrade'</span>, <span class="hljs-function">(<span class="hljs-params">req, socket, head</span>) =></span> {
816  socket.<span class="hljs-title function_">write</span>(<span class="hljs-string">'HTTP/1.1 101 Web Socket Protocol Handshake\r\n'</span> +
817               <span class="hljs-string">'Upgrade: WebSocket\r\n'</span> +
818               <span class="hljs-string">'Connection: Upgrade\r\n'</span> +
819               <span class="hljs-string">'\r\n'</span>);
820
821  socket.<span class="hljs-title function_">pipe</span>(socket); <span class="hljs-comment">// echo back</span>
822});
823
824<span class="hljs-comment">// Now that server is running</span>
825server.<span class="hljs-title function_">listen</span>(<span class="hljs-number">1337</span>, <span class="hljs-string">'127.0.0.1'</span>, <span class="hljs-function">() =></span> {
826
827  <span class="hljs-comment">// make a request</span>
828  <span class="hljs-keyword">const</span> options = {
829    <span class="hljs-attr">port</span>: <span class="hljs-number">1337</span>,
830    <span class="hljs-attr">host</span>: <span class="hljs-string">'127.0.0.1'</span>,
831    <span class="hljs-attr">headers</span>: {
832      <span class="hljs-string">'Connection'</span>: <span class="hljs-string">'Upgrade'</span>,
833      <span class="hljs-string">'Upgrade'</span>: <span class="hljs-string">'websocket'</span>
834    }
835  };
836
837  <span class="hljs-keyword">const</span> req = http.<span class="hljs-title function_">request</span>(options);
838  req.<span class="hljs-title function_">end</span>();
839
840  req.<span class="hljs-title function_">on</span>(<span class="hljs-string">'upgrade'</span>, <span class="hljs-function">(<span class="hljs-params">res, socket, upgradeHead</span>) =></span> {
841    <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'got upgraded!'</span>);
842    socket.<span class="hljs-title function_">end</span>();
843    process.<span class="hljs-title function_">exit</span>(<span class="hljs-number">0</span>);
844  });
845});</code></pre>
846<h4><code>request.abort()</code><span><a class="mark" href="#http_request_abort" id="http_request_abort">#</a></span></h4>
847<div class="api_metadata">
848<span>Added in: v0.3.8</span><span>Deprecated since: v14.1.0</span>
849</div>
850<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated: Use <a href="#http_request_destroy_error"><code>request.destroy()</code></a> instead.</div><p></p>
851<p>Marks the request as aborting. Calling this will cause remaining data
852in the response to be dropped and the socket to be destroyed.</p>
853<h4><code>request.aborted</code><span><a class="mark" href="#http_request_aborted" id="http_request_aborted">#</a></span></h4>
854<div class="api_metadata">
855<details class="changelog"><summary>History</summary>
856<table>
857<tbody><tr><th>Version</th><th>Changes</th></tr>
858<tr><td>v11.0.0</td>
859<td><p>The <code>aborted</code> property is no longer a timestamp number.</p></td></tr>
860<tr><td>v0.11.14</td>
861<td><p><span>Added in: v0.11.14</span></p></td></tr>
862</tbody></table>
863</details>
864</div>
865<ul>
866<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
867</ul>
868<p>The <code>request.aborted</code> property will be <code>true</code> if the request has
869been aborted.</p>
870<h4><code>request.connection</code><span><a class="mark" href="#http_request_connection" id="http_request_connection">#</a></span></h4>
871<div class="api_metadata">
872<span>Added in: v0.3.0</span><span>Deprecated since: v13.0.0</span>
873</div>
874<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated. Use <a href="#http_request_socket"><code>request.socket</code></a>.</div><p></p>
875<ul>
876<li><a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
877</ul>
878<p>See <a href="#http_request_socket"><code>request.socket</code></a>.</p>
879<h4><code>request.end([data[, encoding]][, callback])</code><span><a class="mark" href="#http_request_end_data_encoding_callback" id="http_request_end_data_encoding_callback">#</a></span></h4>
880<div class="api_metadata">
881<details class="changelog"><summary>History</summary>
882<table>
883<tbody><tr><th>Version</th><th>Changes</th></tr>
884<tr><td>v10.0.0</td>
885<td><p>This method now returns a reference to <code>ClientRequest</code>.</p></td></tr>
886<tr><td>v0.1.90</td>
887<td><p><span>Added in: v0.1.90</span></p></td></tr>
888</tbody></table>
889</details>
890</div>
891<ul>
892<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
893<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
894<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
895<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
896</ul>
897<p>Finishes sending the request. If any parts of the body are
898unsent, it will flush them to the stream. If the request is
899chunked, this will send the terminating <code>'0\r\n\r\n'</code>.</p>
900<p>If <code>data</code> is specified, it is equivalent to calling
901<a href="#http_request_write_chunk_encoding_callback"><code>request.write(data, encoding)</code></a> followed by <code>request.end(callback)</code>.</p>
902<p>If <code>callback</code> is specified, it will be called when the request stream
903is finished.</p>
904<h4><code>request.destroy([error])</code><span><a class="mark" href="#http_request_destroy_error" id="http_request_destroy_error">#</a></span></h4>
905<div class="api_metadata">
906<details class="changelog"><summary>History</summary>
907<table>
908<tbody><tr><th>Version</th><th>Changes</th></tr>
909<tr><td>v14.5.0</td>
910<td><p>The function returns <code>this</code> for consistency with other Readable streams.</p></td></tr>
911<tr><td>v0.3.0</td>
912<td><p><span>Added in: v0.3.0</span></p></td></tr>
913</tbody></table>
914</details>
915</div>
916<ul>
917<li><code>error</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a> Optional, an error to emit with <code>'error'</code> event.</li>
918<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
919</ul>
920<p>Destroy the request. Optionally emit an <code>'error'</code> event,
921and emit a <code>'close'</code> event. Calling this will cause remaining data
922in the response to be dropped and the socket to be destroyed.</p>
923<p>See <a href="stream.html#stream_writable_destroy_error"><code>writable.destroy()</code></a> for further details.</p>
924<h5><code>request.destroyed</code><span><a class="mark" href="#http_request_destroyed" id="http_request_destroyed">#</a></span></h5>
925<div class="api_metadata">
926<span>Added in: v14.1.0</span>
927</div>
928<ul>
929<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
930</ul>
931<p>Is <code>true</code> after <a href="#http_request_destroy_error"><code>request.destroy()</code></a> has been called.</p>
932<p>See <a href="stream.html#stream_writable_destroyed"><code>writable.destroyed</code></a> for further details.</p>
933<h4><code>request.finished</code><span><a class="mark" href="#http_request_finished" id="http_request_finished">#</a></span></h4>
934<div class="api_metadata">
935<span>Added in: v0.0.1</span><span>Deprecated since: v13.4.0, v12.16.0</span>
936</div>
937<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated. Use <a href="#http_request_writableended"><code>request.writableEnded</code></a>.</div><p></p>
938<ul>
939<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
940</ul>
941<p>The <code>request.finished</code> property will be <code>true</code> if <a href="#http_request_end_data_encoding_callback"><code>request.end()</code></a>
942has been called. <code>request.end()</code> will automatically be called if the
943request was initiated via <a href="#http_http_get_options_callback"><code>http.get()</code></a>.</p>
944<h4><code>request.flushHeaders()</code><span><a class="mark" href="#http_request_flushheaders" id="http_request_flushheaders">#</a></span></h4>
945<div class="api_metadata">
946<span>Added in: v1.6.0</span>
947</div>
948<p>Flushes the request headers.</p>
949<p>For efficiency reasons, Node.js normally buffers the request headers until
950<code>request.end()</code> is called or the first chunk of request data is written. It
951then tries to pack the request headers and data into a single TCP packet.</p>
952<p>That's usually desired (it saves a TCP round-trip), but not when the first
953data is not sent until possibly much later. <code>request.flushHeaders()</code> bypasses
954the optimization and kickstarts the request.</p>
955<h4><code>request.getHeader(name)</code><span><a class="mark" href="#http_request_getheader_name" id="http_request_getheader_name">#</a></span></h4>
956<div class="api_metadata">
957<span>Added in: v1.6.0</span>
958</div>
959<ul>
960<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
961<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type">&#x3C;any></a></li>
962</ul>
963<p>Reads out a header on the request. The name is case-insensitive.
964The type of the return value depends on the arguments provided to
965<a href="#http_request_setheader_name_value"><code>request.setHeader()</code></a>.</p>
966<pre><code class="language-js">request.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'content-type'</span>, <span class="hljs-string">'text/html'</span>);
967request.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Content-Length'</span>, <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">byteLength</span>(body));
968request.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Cookie'</span>, [<span class="hljs-string">'type=ninja'</span>, <span class="hljs-string">'language=javascript'</span>]);
969<span class="hljs-keyword">const</span> contentType = request.<span class="hljs-title function_">getHeader</span>(<span class="hljs-string">'Content-Type'</span>);
970<span class="hljs-comment">// 'contentType' is 'text/html'</span>
971<span class="hljs-keyword">const</span> contentLength = request.<span class="hljs-title function_">getHeader</span>(<span class="hljs-string">'Content-Length'</span>);
972<span class="hljs-comment">// 'contentLength' is of type number</span>
973<span class="hljs-keyword">const</span> cookie = request.<span class="hljs-title function_">getHeader</span>(<span class="hljs-string">'Cookie'</span>);
974<span class="hljs-comment">// 'cookie' is of type string[]</span></code></pre>
975<h4><code>request.getRawHeaderNames()</code><span><a class="mark" href="#http_request_getrawheadernames" id="http_request_getrawheadernames">#</a></span></h4>
976<div class="api_metadata">
977<span>Added in: v14.17.0</span>
978</div>
979<ul>
980<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
981</ul>
982<p>Returns an array containing the unique names of the current outgoing raw
983headers. Header names are returned with their exact casing being set.</p>
984<pre><code class="language-js">request.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Foo'</span>, <span class="hljs-string">'bar'</span>);
985request.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Set-Cookie'</span>, [<span class="hljs-string">'foo=bar'</span>, <span class="hljs-string">'bar=baz'</span>]);
986
987<span class="hljs-keyword">const</span> headerNames = request.<span class="hljs-title function_">getRawHeaderNames</span>();
988<span class="hljs-comment">// headerNames === ['Foo', 'Set-Cookie']</span></code></pre>
989<h4><code>request.maxHeadersCount</code><span><a class="mark" href="#http_request_maxheaderscount" id="http_request_maxheaderscount">#</a></span></h4>
990<ul>
991<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> <strong>Default:</strong> <code>2000</code></li>
992</ul>
993<p>Limits maximum response headers count. If set to 0, no limit will be applied.</p>
994<h4><code>request.path</code><span><a class="mark" href="#http_request_path" id="http_request_path">#</a></span></h4>
995<div class="api_metadata">
996<span>Added in: v0.4.0</span>
997</div>
998<ul>
999<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The request path.</li>
1000</ul>
1001<h4><code>request.method</code><span><a class="mark" href="#http_request_method" id="http_request_method">#</a></span></h4>
1002<div class="api_metadata">
1003<span>Added in: v0.1.97</span>
1004</div>
1005<ul>
1006<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The request method.</li>
1007</ul>
1008<h4><code>request.host</code><span><a class="mark" href="#http_request_host" id="http_request_host">#</a></span></h4>
1009<div class="api_metadata">
1010<span>Added in: v14.5.0</span>
1011</div>
1012<ul>
1013<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The request host.</li>
1014</ul>
1015<h4><code>request.protocol</code><span><a class="mark" href="#http_request_protocol" id="http_request_protocol">#</a></span></h4>
1016<div class="api_metadata">
1017<span>Added in: v14.5.0</span>
1018</div>
1019<ul>
1020<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The request protocol.</li>
1021</ul>
1022<h4><code>request.removeHeader(name)</code><span><a class="mark" href="#http_request_removeheader_name" id="http_request_removeheader_name">#</a></span></h4>
1023<div class="api_metadata">
1024<span>Added in: v1.6.0</span>
1025</div>
1026<ul>
1027<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1028</ul>
1029<p>Removes a header that's already defined into headers object.</p>
1030<pre><code class="language-js">request.<span class="hljs-title function_">removeHeader</span>(<span class="hljs-string">'Content-Type'</span>);</code></pre>
1031<h4><code>request.reusedSocket</code><span><a class="mark" href="#http_request_reusedsocket" id="http_request_reusedsocket">#</a></span></h4>
1032<div class="api_metadata">
1033<span>Added in: v13.0.0, v12.16.0</span>
1034</div>
1035<ul>
1036<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Whether the request is send through a reused socket.</li>
1037</ul>
1038<p>When sending request through a keep-alive enabled agent, the underlying socket
1039might be reused. But if server closes connection at unfortunate time, client
1040may run into a 'ECONNRESET' error.</p>
1041<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
1042
1043<span class="hljs-comment">// Server has a 5 seconds keep-alive timeout by default</span>
1044http
1045  .<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
1046    res.<span class="hljs-title function_">write</span>(<span class="hljs-string">'hello\n'</span>);
1047    res.<span class="hljs-title function_">end</span>();
1048  })
1049  .<span class="hljs-title function_">listen</span>(<span class="hljs-number">3000</span>);
1050
1051<span class="hljs-built_in">setInterval</span>(<span class="hljs-function">() =></span> {
1052  <span class="hljs-comment">// Adapting a keep-alive agent</span>
1053  http.<span class="hljs-title function_">get</span>(<span class="hljs-string">'http://localhost:3000'</span>, { agent }, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
1054    res.<span class="hljs-title function_">on</span>(<span class="hljs-string">'data'</span>, <span class="hljs-function">(<span class="hljs-params">data</span>) =></span> {
1055      <span class="hljs-comment">// Do nothing</span>
1056    });
1057  });
1058}, <span class="hljs-number">5000</span>); <span class="hljs-comment">// Sending request on 5s interval so it's easy to hit idle timeout</span></code></pre>
1059<p>By marking a request whether it reused socket or not, we can do
1060automatic error retry base on it.</p>
1061<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
1062<span class="hljs-keyword">const</span> agent = <span class="hljs-keyword">new</span> http.<span class="hljs-title class_">Agent</span>({ <span class="hljs-attr">keepAlive</span>: <span class="hljs-literal">true</span> });
1063
1064<span class="hljs-keyword">function</span> <span class="hljs-title function_">retriableRequest</span>(<span class="hljs-params"></span>) {
1065  <span class="hljs-keyword">const</span> req = http
1066    .<span class="hljs-title function_">get</span>(<span class="hljs-string">'http://localhost:3000'</span>, { agent }, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
1067      <span class="hljs-comment">// ...</span>
1068    })
1069    .<span class="hljs-title function_">on</span>(<span class="hljs-string">'error'</span>, <span class="hljs-function">(<span class="hljs-params">err</span>) =></span> {
1070      <span class="hljs-comment">// Check if retry is needed</span>
1071      <span class="hljs-keyword">if</span> (req.<span class="hljs-property">reusedSocket</span> &#x26;&#x26; err.<span class="hljs-property">code</span> === <span class="hljs-string">'ECONNRESET'</span>) {
1072        <span class="hljs-title function_">retriableRequest</span>();
1073      }
1074    });
1075}
1076
1077<span class="hljs-title function_">retriableRequest</span>();</code></pre>
1078<h4><code>request.setHeader(name, value)</code><span><a class="mark" href="#http_request_setheader_name_value" id="http_request_setheader_name_value">#</a></span></h4>
1079<div class="api_metadata">
1080<span>Added in: v1.6.0</span>
1081</div>
1082<ul>
1083<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1084<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type">&#x3C;any></a></li>
1085</ul>
1086<p>Sets a single header value for headers object. If this header already exists in
1087the to-be-sent headers, its value will be replaced. Use an array of strings
1088here to send multiple headers with the same name. Non-string values will be
1089stored without modification. Therefore, <a href="#http_request_getheader_name"><code>request.getHeader()</code></a> may return
1090non-string values. However, the non-string values will be converted to strings
1091for network transmission.</p>
1092<pre><code class="language-js">request.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Content-Type'</span>, <span class="hljs-string">'application/json'</span>);</code></pre>
1093<p>or</p>
1094<pre><code class="language-js">request.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Cookie'</span>, [<span class="hljs-string">'type=ninja'</span>, <span class="hljs-string">'language=javascript'</span>]);</code></pre>
1095<h4><code>request.setNoDelay([noDelay])</code><span><a class="mark" href="#http_request_setnodelay_nodelay" id="http_request_setnodelay_nodelay">#</a></span></h4>
1096<div class="api_metadata">
1097<span>Added in: v0.5.9</span>
1098</div>
1099<ul>
1100<li><code>noDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1101</ul>
1102<p>Once a socket is assigned to this request and is connected
1103<a href="net.html#net_socket_setnodelay_nodelay"><code>socket.setNoDelay()</code></a> will be called.</p>
1104<h4><code>request.setSocketKeepAlive([enable][, initialDelay])</code><span><a class="mark" href="#http_request_setsocketkeepalive_enable_initialdelay" id="http_request_setsocketkeepalive_enable_initialdelay">#</a></span></h4>
1105<div class="api_metadata">
1106<span>Added in: v0.5.9</span>
1107</div>
1108<ul>
1109<li><code>enable</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1110<li><code>initialDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
1111</ul>
1112<p>Once a socket is assigned to this request and is connected
1113<a href="net.html#net_socket_setkeepalive_enable_initialdelay"><code>socket.setKeepAlive()</code></a> will be called.</p>
1114<h4><code>request.setTimeout(timeout[, callback])</code><span><a class="mark" href="#http_request_settimeout_timeout_callback" id="http_request_settimeout_timeout_callback">#</a></span></h4>
1115<div class="api_metadata">
1116<details class="changelog"><summary>History</summary>
1117<table>
1118<tbody><tr><th>Version</th><th>Changes</th></tr>
1119<tr><td>v9.0.0</td>
1120<td><p>Consistently set socket timeout only when the socket connects.</p></td></tr>
1121<tr><td>v0.5.9</td>
1122<td><p><span>Added in: v0.5.9</span></p></td></tr>
1123</tbody></table>
1124</details>
1125</div>
1126<ul>
1127<li><code>timeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Milliseconds before a request times out.</li>
1128<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Optional function to be called when a timeout occurs.
1129Same as binding to the <code>'timeout'</code> event.</li>
1130<li>Returns: <a href="http.html#http_class_http_clientrequest" class="type">&#x3C;http.ClientRequest></a></li>
1131</ul>
1132<p>Once a socket is assigned to this request and is connected
1133<a href="net.html#net_socket_settimeout_timeout_callback"><code>socket.setTimeout()</code></a> will be called.</p>
1134<h4><code>request.socket</code><span><a class="mark" href="#http_request_socket" id="http_request_socket">#</a></span></h4>
1135<div class="api_metadata">
1136<span>Added in: v0.3.0</span>
1137</div>
1138<ul>
1139<li><a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
1140</ul>
1141<p>Reference to the underlying socket. Usually users will not want to access
1142this property. In particular, the socket will not emit <code>'readable'</code> events
1143because of how the protocol parser attaches to the socket.</p>
1144<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
1145<span class="hljs-keyword">const</span> options = {
1146  <span class="hljs-attr">host</span>: <span class="hljs-string">'www.google.com'</span>,
1147};
1148<span class="hljs-keyword">const</span> req = http.<span class="hljs-title function_">get</span>(options);
1149req.<span class="hljs-title function_">end</span>();
1150req.<span class="hljs-title function_">once</span>(<span class="hljs-string">'response'</span>, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
1151  <span class="hljs-keyword">const</span> ip = req.<span class="hljs-property">socket</span>.<span class="hljs-property">localAddress</span>;
1152  <span class="hljs-keyword">const</span> port = req.<span class="hljs-property">socket</span>.<span class="hljs-property">localPort</span>;
1153  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`Your IP address is <span class="hljs-subst">${ip}</span> and your source port is <span class="hljs-subst">${port}</span>.`</span>);
1154  <span class="hljs-comment">// Consume response object</span>
1155});</code></pre>
1156<p>This property is guaranteed to be an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
1157a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specified a socket
1158type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
1159<h4><code>request.writableEnded</code><span><a class="mark" href="#http_request_writableended" id="http_request_writableended">#</a></span></h4>
1160<div class="api_metadata">
1161<span>Added in: v12.9.0</span>
1162</div>
1163<ul>
1164<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1165</ul>
1166<p>Is <code>true</code> after <a href="#http_request_end_data_encoding_callback"><code>request.end()</code></a> has been called. This property
1167does not indicate whether the data has been flushed, for this use
1168<a href="#http_request_writablefinished"><code>request.writableFinished</code></a> instead.</p>
1169<h4><code>request.writableFinished</code><span><a class="mark" href="#http_request_writablefinished" id="http_request_writablefinished">#</a></span></h4>
1170<div class="api_metadata">
1171<span>Added in: v12.7.0</span>
1172</div>
1173<ul>
1174<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1175</ul>
1176<p>Is <code>true</code> if all data has been flushed to the underlying system, immediately
1177before the <a href="#http_event_finish"><code>'finish'</code></a> event is emitted.</p>
1178<h4><code>request.write(chunk[, encoding][, callback])</code><span><a class="mark" href="#http_request_write_chunk_encoding_callback" id="http_request_write_chunk_encoding_callback">#</a></span></h4>
1179<div class="api_metadata">
1180<span>Added in: v0.1.29</span>
1181</div>
1182<ul>
1183<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
1184<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1185<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1186<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1187</ul>
1188<p>Sends a chunk of the body. This method can be called multiple times. If no
1189<code>Content-Length</code> is set, data will automatically be encoded in HTTP Chunked
1190transfer encoding, so that server knows when the data ends. The
1191<code>Transfer-Encoding: chunked</code> header is added. Calling <a href="#http_request_end_data_encoding_callback"><code>request.end()</code></a>
1192is necessary to finish sending the request.</p>
1193<p>The <code>encoding</code> argument is optional and only applies when <code>chunk</code> is a string.
1194Defaults to <code>'utf8'</code>.</p>
1195<p>The <code>callback</code> argument is optional and will be called when this chunk of data
1196is flushed, but only if the chunk is non-empty.</p>
1197<p>Returns <code>true</code> if the entire data was flushed successfully to the kernel
1198buffer. Returns <code>false</code> if all or part of the data was queued in user memory.
1199<code>'drain'</code> will be emitted when the buffer is free again.</p>
1200<p>When <code>write</code> function is called with empty string or buffer, it does
1201nothing and waits for more input.</p>
1202</section><section><h3>Class: <code>http.Server</code><span><a class="mark" href="#http_class_http_server" id="http_class_http_server">#</a></span></h3>
1203<div class="api_metadata">
1204<span>Added in: v0.1.17</span>
1205</div>
1206<ul>
1207<li>Extends: <a href="net.html#net_class_net_server" class="type">&#x3C;net.Server></a></li>
1208</ul>
1209<h4>Event: <code>'checkContinue'</code><span><a class="mark" href="#http_event_checkcontinue" id="http_event_checkcontinue">#</a></span></h4>
1210<div class="api_metadata">
1211<span>Added in: v0.3.0</span>
1212</div>
1213<ul>
1214<li><code>request</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a></li>
1215<li><code>response</code> <a href="http.html#http_class_http_serverresponse" class="type">&#x3C;http.ServerResponse></a></li>
1216</ul>
1217<p>Emitted each time a request with an HTTP <code>Expect: 100-continue</code> is received.
1218If this event is not listened for, the server will automatically respond
1219with a <code>100 Continue</code> as appropriate.</p>
1220<p>Handling this event involves calling <a href="#http_response_writecontinue"><code>response.writeContinue()</code></a> if the
1221client should continue to send the request body, or generating an appropriate
1222HTTP response (e.g. 400 Bad Request) if the client should not continue to send
1223the request body.</p>
1224<p>When this event is emitted and handled, the <a href="#http_event_request"><code>'request'</code></a> event will
1225not be emitted.</p>
1226<h4>Event: <code>'checkExpectation'</code><span><a class="mark" href="#http_event_checkexpectation" id="http_event_checkexpectation">#</a></span></h4>
1227<div class="api_metadata">
1228<span>Added in: v5.5.0</span>
1229</div>
1230<ul>
1231<li><code>request</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a></li>
1232<li><code>response</code> <a href="http.html#http_class_http_serverresponse" class="type">&#x3C;http.ServerResponse></a></li>
1233</ul>
1234<p>Emitted each time a request with an HTTP <code>Expect</code> header is received, where the
1235value is not <code>100-continue</code>. If this event is not listened for, the server will
1236automatically respond with a <code>417 Expectation Failed</code> as appropriate.</p>
1237<p>When this event is emitted and handled, the <a href="#http_event_request"><code>'request'</code></a> event will
1238not be emitted.</p>
1239<h4>Event: <code>'clientError'</code><span><a class="mark" href="#http_event_clienterror" id="http_event_clienterror">#</a></span></h4>
1240<div class="api_metadata">
1241<details class="changelog"><summary>History</summary>
1242<table>
1243<tbody><tr><th>Version</th><th>Changes</th></tr>
1244<tr><td>v12.0.0</td>
1245<td><p>The default behavior will return a 431 Request Header Fields Too Large if a HPE_HEADER_OVERFLOW error occurs.</p></td></tr>
1246<tr><td>v9.4.0</td>
1247<td><p>The <code>rawPacket</code> is the current buffer that just parsed. Adding this buffer to the error object of <code>'clientError'</code> event is to make it possible that developers can log the broken packet.</p></td></tr>
1248<tr><td>v6.0.0</td>
1249<td><p>The default action of calling <code>.destroy()</code> on the <code>socket</code> will no longer take place if there are listeners attached for <code>'clientError'</code>.</p></td></tr>
1250<tr><td>v0.1.94</td>
1251<td><p><span>Added in: v0.1.94</span></p></td></tr>
1252</tbody></table>
1253</details>
1254</div>
1255<ul>
1256<li><code>exception</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a></li>
1257<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
1258</ul>
1259<p>If a client connection emits an <code>'error'</code> event, it will be forwarded here.
1260Listener of this event is responsible for closing/destroying the underlying
1261socket. For example, one may wish to more gracefully close the socket with a
1262custom HTTP response instead of abruptly severing the connection.</p>
1263<p>This event is guaranteed to be passed an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
1264a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
1265type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
1266<p>Default behavior is to try close the socket with a HTTP '400 Bad Request',
1267or a HTTP '431 Request Header Fields Too Large' in the case of a
1268<a href="errors.html#errors_hpe_header_overflow"><code>HPE_HEADER_OVERFLOW</code></a> error. If the socket is not writable or has already
1269written data it is immediately destroyed.</p>
1270<p><code>socket</code> is the <a href="net.html#net_class_net_socket"><code>net.Socket</code></a> object that the error originated from.</p>
1271<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
1272
1273<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
1274  res.<span class="hljs-title function_">end</span>();
1275});
1276server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'clientError'</span>, <span class="hljs-function">(<span class="hljs-params">err, socket</span>) =></span> {
1277  socket.<span class="hljs-title function_">end</span>(<span class="hljs-string">'HTTP/1.1 400 Bad Request\r\n\r\n'</span>);
1278});
1279server.<span class="hljs-title function_">listen</span>(<span class="hljs-number">8000</span>);</code></pre>
1280<p>When the <code>'clientError'</code> event occurs, there is no <code>request</code> or <code>response</code>
1281object, so any HTTP response sent, including response headers and payload,
1282<em>must</em> be written directly to the <code>socket</code> object. Care must be taken to
1283ensure the response is a properly formatted HTTP response message.</p>
1284<p><code>err</code> is an instance of <code>Error</code> with two extra columns:</p>
1285<ul>
1286<li><code>bytesParsed</code>: the bytes count of request packet that Node.js may have parsed
1287correctly;</li>
1288<li><code>rawPacket</code>: the raw packet of current request.</li>
1289</ul>
1290<p>In some cases, the client has already received the response and/or the socket
1291has already been destroyed, like in case of <code>ECONNRESET</code> errors. Before
1292trying to send data to the socket, it is better to check that it is still
1293writable.</p>
1294<pre><code class="language-js">server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'clientError'</span>, <span class="hljs-function">(<span class="hljs-params">err, socket</span>) =></span> {
1295  <span class="hljs-keyword">if</span> (err.<span class="hljs-property">code</span> === <span class="hljs-string">'ECONNRESET'</span> || !socket.<span class="hljs-property">writable</span>) {
1296    <span class="hljs-keyword">return</span>;
1297  }
1298
1299  socket.<span class="hljs-title function_">end</span>(<span class="hljs-string">'HTTP/1.1 400 Bad Request\r\n\r\n'</span>);
1300});</code></pre>
1301<h4>Event: <code>'close'</code><span><a class="mark" href="#http_event_close" id="http_event_close">#</a></span></h4>
1302<div class="api_metadata">
1303<span>Added in: v0.1.4</span>
1304</div>
1305<p>Emitted when the server closes.</p>
1306<h4>Event: <code>'connect'</code><span><a class="mark" href="#http_event_connect_1" id="http_event_connect_1">#</a></span></h4>
1307<div class="api_metadata">
1308<span>Added in: v0.7.0</span>
1309</div>
1310<ul>
1311<li><code>request</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a> Arguments for the HTTP request, as it is in
1312the <a href="#http_event_request"><code>'request'</code></a> event</li>
1313<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a> Network socket between the server and client</li>
1314<li><code>head</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The first packet of the tunneling stream (may be empty)</li>
1315</ul>
1316<p>Emitted each time a client requests an HTTP <code>CONNECT</code> method. If this event is
1317not listened for, then clients requesting a <code>CONNECT</code> method will have their
1318connections closed.</p>
1319<p>This event is guaranteed to be passed an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
1320a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
1321type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
1322<p>After this event is emitted, the request's socket will not have a <code>'data'</code>
1323event listener, meaning it will need to be bound in order to handle data
1324sent to the server on that socket.</p>
1325<h4>Event: <code>'connection'</code><span><a class="mark" href="#http_event_connection" id="http_event_connection">#</a></span></h4>
1326<div class="api_metadata">
1327<span>Added in: v0.1.0</span>
1328</div>
1329<ul>
1330<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
1331</ul>
1332<p>This event is emitted when a new TCP stream is established. <code>socket</code> is
1333typically an object of type <a href="net.html#net_class_net_socket"><code>net.Socket</code></a>. Usually users will not want to
1334access this event. In particular, the socket will not emit <code>'readable'</code> events
1335because of how the protocol parser attaches to the socket. The <code>socket</code> can
1336also be accessed at <code>request.socket</code>.</p>
1337<p>This event can also be explicitly emitted by users to inject connections
1338into the HTTP server. In that case, any <a href="stream.html#stream_class_stream_duplex"><code>Duplex</code></a> stream can be passed.</p>
1339<p>If <code>socket.setTimeout()</code> is called here, the timeout will be replaced with
1340<code>server.keepAliveTimeout</code> when the socket has served a request (if
1341<code>server.keepAliveTimeout</code> is non-zero).</p>
1342<p>This event is guaranteed to be passed an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
1343a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
1344type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
1345<h4>Event: <code>'request'</code><span><a class="mark" href="#http_event_request" id="http_event_request">#</a></span></h4>
1346<div class="api_metadata">
1347<span>Added in: v0.1.0</span>
1348</div>
1349<ul>
1350<li><code>request</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a></li>
1351<li><code>response</code> <a href="http.html#http_class_http_serverresponse" class="type">&#x3C;http.ServerResponse></a></li>
1352</ul>
1353<p>Emitted each time there is a request. There may be multiple requests
1354per connection (in the case of HTTP Keep-Alive connections).</p>
1355<h4>Event: <code>'upgrade'</code><span><a class="mark" href="#http_event_upgrade_1" id="http_event_upgrade_1">#</a></span></h4>
1356<div class="api_metadata">
1357<details class="changelog"><summary>History</summary>
1358<table>
1359<tbody><tr><th>Version</th><th>Changes</th></tr>
1360<tr><td>v10.0.0</td>
1361<td><p>Not listening to this event no longer causes the socket to be destroyed if a client sends an Upgrade header.</p></td></tr>
1362<tr><td>v0.1.94</td>
1363<td><p><span>Added in: v0.1.94</span></p></td></tr>
1364</tbody></table>
1365</details>
1366</div>
1367<ul>
1368<li><code>request</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a> Arguments for the HTTP request, as it is in
1369the <a href="#http_event_request"><code>'request'</code></a> event</li>
1370<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a> Network socket between the server and client</li>
1371<li><code>head</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The first packet of the upgraded stream (may be empty)</li>
1372</ul>
1373<p>Emitted each time a client requests an HTTP upgrade. Listening to this event
1374is optional and clients cannot insist on a protocol change.</p>
1375<p>After this event is emitted, the request's socket will not have a <code>'data'</code>
1376event listener, meaning it will need to be bound in order to handle data
1377sent to the server on that socket.</p>
1378<p>This event is guaranteed to be passed an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
1379a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specifies a socket
1380type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
1381<h4><code>server.close([callback])</code><span><a class="mark" href="#http_server_close_callback" id="http_server_close_callback">#</a></span></h4>
1382<div class="api_metadata">
1383<span>Added in: v0.1.90</span>
1384</div>
1385<ul>
1386<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1387</ul>
1388<p>Stops the server from accepting new connections. See <a href="net.html#net_server_close_callback"><code>net.Server.close()</code></a>.</p>
1389<h4><code>server.headersTimeout</code><span><a class="mark" href="#http_server_headerstimeout" id="http_server_headerstimeout">#</a></span></h4>
1390<div class="api_metadata">
1391<span>Added in: v11.3.0, v10.14.0</span>
1392</div>
1393<ul>
1394<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> <strong>Default:</strong> <code>60000</code></li>
1395</ul>
1396<p>Limit the amount of time the parser will wait to receive the complete HTTP
1397headers.</p>
1398<p>In case of inactivity, the rules defined in <a href="#http_server_timeout"><code>server.timeout</code></a> apply. However,
1399that inactivity based timeout would still allow the connection to be kept open
1400if the headers are being sent very slowly (by default, up to a byte per 2
1401minutes). In order to prevent this, whenever header data arrives an additional
1402check is made that more than <code>server.headersTimeout</code> milliseconds has not
1403passed since the connection was established. If the check fails, a <code>'timeout'</code>
1404event is emitted on the server object, and (by default) the socket is destroyed.
1405See <a href="#http_server_timeout"><code>server.timeout</code></a> for more information on how timeout behavior can be
1406customized.</p>
1407<h4><code>server.listen()</code><span><a class="mark" href="#http_server_listen" id="http_server_listen">#</a></span></h4>
1408<p>Starts the HTTP server listening for connections.
1409This method is identical to <a href="net.html#net_server_listen"><code>server.listen()</code></a> from <a href="net.html#net_class_net_server"><code>net.Server</code></a>.</p>
1410<h4><code>server.listening</code><span><a class="mark" href="#http_server_listening" id="http_server_listening">#</a></span></h4>
1411<div class="api_metadata">
1412<span>Added in: v5.7.0</span>
1413</div>
1414<ul>
1415<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Indicates whether or not the server is listening for connections.</li>
1416</ul>
1417<h4><code>server.maxHeadersCount</code><span><a class="mark" href="#http_server_maxheaderscount" id="http_server_maxheaderscount">#</a></span></h4>
1418<div class="api_metadata">
1419<span>Added in: v0.7.0</span>
1420</div>
1421<ul>
1422<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> <strong>Default:</strong> <code>2000</code></li>
1423</ul>
1424<p>Limits maximum incoming headers count. If set to 0, no limit will be applied.</p>
1425<h4><code>server.requestTimeout</code><span><a class="mark" href="#http_server_requesttimeout" id="http_server_requesttimeout">#</a></span></h4>
1426<div class="api_metadata">
1427<span>Added in: v14.11.0</span>
1428</div>
1429<ul>
1430<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> <strong>Default:</strong> <code>0</code></li>
1431</ul>
1432<p>Sets the timeout value in milliseconds for receiving the entire request from
1433the client.</p>
1434<p>If the timeout expires, the server responds with status 408 without
1435forwarding the request to the request listener and then closes the connection.</p>
1436<p>It must be set to a non-zero value (e.g. 120 seconds) to protect against
1437potential Denial-of-Service attacks in case the server is deployed without a
1438reverse proxy in front.</p>
1439<h4><code>server.setTimeout([msecs][, callback])</code><span><a class="mark" href="#http_server_settimeout_msecs_callback" id="http_server_settimeout_msecs_callback">#</a></span></h4>
1440<div class="api_metadata">
1441<details class="changelog"><summary>History</summary>
1442<table>
1443<tbody><tr><th>Version</th><th>Changes</th></tr>
1444<tr><td>v13.0.0</td>
1445<td><p>The default timeout changed from 120s to 0 (no timeout).</p></td></tr>
1446<tr><td>v0.9.12</td>
1447<td><p><span>Added in: v0.9.12</span></p></td></tr>
1448</tbody></table>
1449</details>
1450</div>
1451<ul>
1452<li><code>msecs</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> <strong>Default:</strong> 0 (no timeout)</li>
1453<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1454<li>Returns: <a href="http.html#http_class_http_server" class="type">&#x3C;http.Server></a></li>
1455</ul>
1456<p>Sets the timeout value for sockets, and emits a <code>'timeout'</code> event on
1457the Server object, passing the socket as an argument, if a timeout
1458occurs.</p>
1459<p>If there is a <code>'timeout'</code> event listener on the Server object, then it
1460will be called with the timed-out socket as an argument.</p>
1461<p>By default, the Server does not timeout sockets. However, if a callback
1462is assigned to the Server's <code>'timeout'</code> event, timeouts must be handled
1463explicitly.</p>
1464<h4><code>server.timeout</code><span><a class="mark" href="#http_server_timeout" id="http_server_timeout">#</a></span></h4>
1465<div class="api_metadata">
1466<details class="changelog"><summary>History</summary>
1467<table>
1468<tbody><tr><th>Version</th><th>Changes</th></tr>
1469<tr><td>v13.0.0</td>
1470<td><p>The default timeout changed from 120s to 0 (no timeout).</p></td></tr>
1471<tr><td>v0.9.12</td>
1472<td><p><span>Added in: v0.9.12</span></p></td></tr>
1473</tbody></table>
1474</details>
1475</div>
1476<ul>
1477<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Timeout in milliseconds. <strong>Default:</strong> 0 (no timeout)</li>
1478</ul>
1479<p>The number of milliseconds of inactivity before a socket is presumed
1480to have timed out.</p>
1481<p>A value of <code>0</code> will disable the timeout behavior on incoming connections.</p>
1482<p>The socket timeout logic is set up on connection, so changing this
1483value only affects new connections to the server, not any existing connections.</p>
1484<h4><code>server.keepAliveTimeout</code><span><a class="mark" href="#http_server_keepalivetimeout" id="http_server_keepalivetimeout">#</a></span></h4>
1485<div class="api_metadata">
1486<span>Added in: v8.0.0</span>
1487</div>
1488<ul>
1489<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Timeout in milliseconds. <strong>Default:</strong> <code>5000</code> (5 seconds).</li>
1490</ul>
1491<p>The number of milliseconds of inactivity a server needs to wait for additional
1492incoming data, after it has finished writing the last response, before a socket
1493will be destroyed. If the server receives new data before the keep-alive
1494timeout has fired, it will reset the regular inactivity timeout, i.e.,
1495<a href="#http_server_timeout"><code>server.timeout</code></a>.</p>
1496<p>A value of <code>0</code> will disable the keep-alive timeout behavior on incoming
1497connections.
1498A value of <code>0</code> makes the http server behave similarly to Node.js versions prior
1499to 8.0.0, which did not have a keep-alive timeout.</p>
1500<p>The socket timeout logic is set up on connection, so changing this value only
1501affects new connections to the server, not any existing connections.</p>
1502</section><section><h3>Class: <code>http.ServerResponse</code><span><a class="mark" href="#http_class_http_serverresponse" id="http_class_http_serverresponse">#</a></span></h3>
1503<div class="api_metadata">
1504<span>Added in: v0.1.17</span>
1505</div>
1506<ul>
1507<li>Extends: <a href="stream.html#stream_stream" class="type">&#x3C;Stream></a></li>
1508</ul>
1509<p>This object is created internally by an HTTP server, not by the user. It is
1510passed as the second parameter to the <a href="#http_event_request"><code>'request'</code></a> event.</p>
1511<h4>Event: <code>'close'</code><span><a class="mark" href="#http_event_close_1" id="http_event_close_1">#</a></span></h4>
1512<div class="api_metadata">
1513<span>Added in: v0.6.7</span>
1514</div>
1515<p>Indicates that the response is completed, or its underlying connection was
1516terminated prematurely (before the response completion).</p>
1517<h4>Event: <code>'finish'</code><span><a class="mark" href="#http_event_finish" id="http_event_finish">#</a></span></h4>
1518<div class="api_metadata">
1519<span>Added in: v0.3.6</span>
1520</div>
1521<p>Emitted when the response has been sent. More specifically, this event is
1522emitted when the last segment of the response headers and body have been
1523handed off to the operating system for transmission over the network. It
1524does not imply that the client has received anything yet.</p>
1525<h4><code>response.addTrailers(headers)</code><span><a class="mark" href="#http_response_addtrailers_headers" id="http_response_addtrailers_headers">#</a></span></h4>
1526<div class="api_metadata">
1527<span>Added in: v0.3.0</span>
1528</div>
1529<ul>
1530<li><code>headers</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
1531</ul>
1532<p>This method adds HTTP trailing headers (a header but at the end of the
1533message) to the response.</p>
1534<p>Trailers will <strong>only</strong> be emitted if chunked encoding is used for the
1535response; if it is not (e.g. if the request was HTTP/1.0), they will
1536be silently discarded.</p>
1537<p>HTTP requires the <code>Trailer</code> header to be sent in order to
1538emit trailers, with a list of the header fields in its value. E.g.,</p>
1539<pre><code class="language-js">response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'text/plain'</span>,
1540                          <span class="hljs-string">'Trailer'</span>: <span class="hljs-string">'Content-MD5'</span> });
1541response.<span class="hljs-title function_">write</span>(fileData);
1542response.<span class="hljs-title function_">addTrailers</span>({ <span class="hljs-string">'Content-MD5'</span>: <span class="hljs-string">'7895bf4b8828b55ceaf47747b4bca667'</span> });
1543response.<span class="hljs-title function_">end</span>();</code></pre>
1544<p>Attempting to set a header field name or value that contains invalid characters
1545will result in a <a href="errors.html#errors_class_typeerror"><code>TypeError</code></a> being thrown.</p>
1546<h4><code>response.connection</code><span><a class="mark" href="#http_response_connection" id="http_response_connection">#</a></span></h4>
1547<div class="api_metadata">
1548<span>Added in: v0.3.0</span><span>Deprecated since: v13.0.0</span>
1549</div>
1550<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated. Use <a href="#http_response_socket"><code>response.socket</code></a>.</div><p></p>
1551<ul>
1552<li><a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
1553</ul>
1554<p>See <a href="#http_response_socket"><code>response.socket</code></a>.</p>
1555<h4><code>response.cork()</code><span><a class="mark" href="#http_response_cork" id="http_response_cork">#</a></span></h4>
1556<div class="api_metadata">
1557<span>Added in: v13.2.0, v12.16.0</span>
1558</div>
1559<p>See <a href="stream.html#stream_writable_cork"><code>writable.cork()</code></a>.</p>
1560<h4><code>response.end([data[, encoding]][, callback])</code><span><a class="mark" href="#http_response_end_data_encoding_callback" id="http_response_end_data_encoding_callback">#</a></span></h4>
1561<div class="api_metadata">
1562<details class="changelog"><summary>History</summary>
1563<table>
1564<tbody><tr><th>Version</th><th>Changes</th></tr>
1565<tr><td>v10.0.0</td>
1566<td><p>This method now returns a reference to <code>ServerResponse</code>.</p></td></tr>
1567<tr><td>v0.1.90</td>
1568<td><p><span>Added in: v0.1.90</span></p></td></tr>
1569</tbody></table>
1570</details>
1571</div>
1572<ul>
1573<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
1574<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1575<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1576<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
1577</ul>
1578<p>This method signals to the server that all of the response headers and body
1579have been sent; that server should consider this message complete.
1580The method, <code>response.end()</code>, MUST be called on each response.</p>
1581<p>If <code>data</code> is specified, it is similar in effect to calling
1582<a href="#http_response_write_chunk_encoding_callback"><code>response.write(data, encoding)</code></a> followed by <code>response.end(callback)</code>.</p>
1583<p>If <code>callback</code> is specified, it will be called when the response stream
1584is finished.</p>
1585<h4><code>response.finished</code><span><a class="mark" href="#http_response_finished" id="http_response_finished">#</a></span></h4>
1586<div class="api_metadata">
1587<span>Added in: v0.0.2</span><span>Deprecated since: v13.4.0, v12.16.0</span>
1588</div>
1589<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated. Use <a href="#http_response_writableended"><code>response.writableEnded</code></a>.</div><p></p>
1590<ul>
1591<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1592</ul>
1593<p>The <code>response.finished</code> property will be <code>true</code> if <a href="#http_response_end_data_encoding_callback"><code>response.end()</code></a>
1594has been called.</p>
1595<h4><code>response.flushHeaders()</code><span><a class="mark" href="#http_response_flushheaders" id="http_response_flushheaders">#</a></span></h4>
1596<div class="api_metadata">
1597<span>Added in: v1.6.0</span>
1598</div>
1599<p>Flushes the response headers. See also: <a href="#http_request_flushheaders"><code>request.flushHeaders()</code></a>.</p>
1600<h4><code>response.getHeader(name)</code><span><a class="mark" href="#http_response_getheader_name" id="http_response_getheader_name">#</a></span></h4>
1601<div class="api_metadata">
1602<span>Added in: v0.4.0</span>
1603</div>
1604<ul>
1605<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1606<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type">&#x3C;any></a></li>
1607</ul>
1608<p>Reads out a header that's already been queued but not sent to the client.
1609The name is case-insensitive. The type of the return value depends
1610on the arguments provided to <a href="#http_response_setheader_name_value"><code>response.setHeader()</code></a>.</p>
1611<pre><code class="language-js">response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Content-Type'</span>, <span class="hljs-string">'text/html'</span>);
1612response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Content-Length'</span>, <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">byteLength</span>(body));
1613response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Set-Cookie'</span>, [<span class="hljs-string">'type=ninja'</span>, <span class="hljs-string">'language=javascript'</span>]);
1614<span class="hljs-keyword">const</span> contentType = response.<span class="hljs-title function_">getHeader</span>(<span class="hljs-string">'content-type'</span>);
1615<span class="hljs-comment">// contentType is 'text/html'</span>
1616<span class="hljs-keyword">const</span> contentLength = response.<span class="hljs-title function_">getHeader</span>(<span class="hljs-string">'Content-Length'</span>);
1617<span class="hljs-comment">// contentLength is of type number</span>
1618<span class="hljs-keyword">const</span> setCookie = response.<span class="hljs-title function_">getHeader</span>(<span class="hljs-string">'set-cookie'</span>);
1619<span class="hljs-comment">// setCookie is of type string[]</span></code></pre>
1620<h4><code>response.getHeaderNames()</code><span><a class="mark" href="#http_response_getheadernames" id="http_response_getheadernames">#</a></span></h4>
1621<div class="api_metadata">
1622<span>Added in: v7.7.0</span>
1623</div>
1624<ul>
1625<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
1626</ul>
1627<p>Returns an array containing the unique names of the current outgoing headers.
1628All header names are lowercase.</p>
1629<pre><code class="language-js">response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Foo'</span>, <span class="hljs-string">'bar'</span>);
1630response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Set-Cookie'</span>, [<span class="hljs-string">'foo=bar'</span>, <span class="hljs-string">'bar=baz'</span>]);
1631
1632<span class="hljs-keyword">const</span> headerNames = response.<span class="hljs-title function_">getHeaderNames</span>();
1633<span class="hljs-comment">// headerNames === ['foo', 'set-cookie']</span></code></pre>
1634<h4><code>response.getHeaders()</code><span><a class="mark" href="#http_response_getheaders" id="http_response_getheaders">#</a></span></h4>
1635<div class="api_metadata">
1636<span>Added in: v7.7.0</span>
1637</div>
1638<ul>
1639<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
1640</ul>
1641<p>Returns a shallow copy of the current outgoing headers. Since a shallow copy
1642is used, array values may be mutated without additional calls to various
1643header-related http module methods. The keys of the returned object are the
1644header names and the values are the respective header values. All header names
1645are lowercase.</p>
1646<p>The object returned by the <code>response.getHeaders()</code> method <em>does not</em>
1647prototypically inherit from the JavaScript <code>Object</code>. This means that typical
1648<code>Object</code> methods such as <code>obj.toString()</code>, <code>obj.hasOwnProperty()</code>, and others
1649are not defined and <em>will not work</em>.</p>
1650<pre><code class="language-js">response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Foo'</span>, <span class="hljs-string">'bar'</span>);
1651response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Set-Cookie'</span>, [<span class="hljs-string">'foo=bar'</span>, <span class="hljs-string">'bar=baz'</span>]);
1652
1653<span class="hljs-keyword">const</span> headers = response.<span class="hljs-title function_">getHeaders</span>();
1654<span class="hljs-comment">// headers === { foo: 'bar', 'set-cookie': ['foo=bar', 'bar=baz'] }</span></code></pre>
1655<h4><code>response.hasHeader(name)</code><span><a class="mark" href="#http_response_hasheader_name" id="http_response_hasheader_name">#</a></span></h4>
1656<div class="api_metadata">
1657<span>Added in: v7.7.0</span>
1658</div>
1659<ul>
1660<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1661<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1662</ul>
1663<p>Returns <code>true</code> if the header identified by <code>name</code> is currently set in the
1664outgoing headers. The header name matching is case-insensitive.</p>
1665<pre><code class="language-js"><span class="hljs-keyword">const</span> hasContentType = response.<span class="hljs-title function_">hasHeader</span>(<span class="hljs-string">'content-type'</span>);</code></pre>
1666<h4><code>response.headersSent</code><span><a class="mark" href="#http_response_headerssent" id="http_response_headerssent">#</a></span></h4>
1667<div class="api_metadata">
1668<span>Added in: v0.9.3</span>
1669</div>
1670<ul>
1671<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1672</ul>
1673<p>Boolean (read-only). True if headers were sent, false otherwise.</p>
1674<h4><code>response.removeHeader(name)</code><span><a class="mark" href="#http_response_removeheader_name" id="http_response_removeheader_name">#</a></span></h4>
1675<div class="api_metadata">
1676<span>Added in: v0.4.0</span>
1677</div>
1678<ul>
1679<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1680</ul>
1681<p>Removes a header that's queued for implicit sending.</p>
1682<pre><code class="language-js">response.<span class="hljs-title function_">removeHeader</span>(<span class="hljs-string">'Content-Encoding'</span>);</code></pre>
1683<h4><code>response.sendDate</code><span><a class="mark" href="#http_response_senddate" id="http_response_senddate">#</a></span></h4>
1684<div class="api_metadata">
1685<span>Added in: v0.7.5</span>
1686</div>
1687<ul>
1688<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1689</ul>
1690<p>When true, the Date header will be automatically generated and sent in
1691the response if it is not already present in the headers. Defaults to true.</p>
1692<p>This should only be disabled for testing; HTTP requires the Date header
1693in responses.</p>
1694<h4><code>response.setHeader(name, value)</code><span><a class="mark" href="#http_response_setheader_name_value" id="http_response_setheader_name_value">#</a></span></h4>
1695<div class="api_metadata">
1696<span>Added in: v0.4.0</span>
1697</div>
1698<ul>
1699<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1700<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type">&#x3C;any></a></li>
1701<li>Returns: <a href="http.html#http_class_http_serverresponse" class="type">&#x3C;http.ServerResponse></a></li>
1702</ul>
1703<p>Returns the response object.</p>
1704<p>Sets a single header value for implicit headers. If this header already exists
1705in the to-be-sent headers, its value will be replaced. Use an array of strings
1706here to send multiple headers with the same name. Non-string values will be
1707stored without modification. Therefore, <a href="#http_response_getheader_name"><code>response.getHeader()</code></a> may return
1708non-string values. However, the non-string values will be converted to strings
1709for network transmission. The same response object is returned to the caller,
1710to enable call chaining.</p>
1711<pre><code class="language-js">response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Content-Type'</span>, <span class="hljs-string">'text/html'</span>);</code></pre>
1712<p>or</p>
1713<pre><code class="language-js">response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Set-Cookie'</span>, [<span class="hljs-string">'type=ninja'</span>, <span class="hljs-string">'language=javascript'</span>]);</code></pre>
1714<p>Attempting to set a header field name or value that contains invalid characters
1715will result in a <a href="errors.html#errors_class_typeerror"><code>TypeError</code></a> being thrown.</p>
1716<p>When headers have been set with <a href="#http_response_setheader_name_value"><code>response.setHeader()</code></a>, they will be merged
1717with any headers passed to <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a>, with the headers passed
1718to <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a> given precedence.</p>
1719<pre><code class="language-js"><span class="hljs-comment">// Returns content-type = text/plain</span>
1720<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
1721  res.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Content-Type'</span>, <span class="hljs-string">'text/html'</span>);
1722  res.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'X-Foo'</span>, <span class="hljs-string">'bar'</span>);
1723  res.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'text/plain'</span> });
1724  res.<span class="hljs-title function_">end</span>(<span class="hljs-string">'ok'</span>);
1725});</code></pre>
1726<p>If <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a> method is called and this method has not been
1727called, it will directly write the supplied header values onto the network
1728channel without caching internally, and the <a href="#http_response_getheader_name"><code>response.getHeader()</code></a> on the
1729header will not yield the expected result. If progressive population of headers
1730is desired with potential future retrieval and modification, use
1731<a href="#http_response_setheader_name_value"><code>response.setHeader()</code></a> instead of <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a>.</p>
1732<h4><code>response.setTimeout(msecs[, callback])</code><span><a class="mark" href="#http_response_settimeout_msecs_callback" id="http_response_settimeout_msecs_callback">#</a></span></h4>
1733<div class="api_metadata">
1734<span>Added in: v0.9.12</span>
1735</div>
1736<ul>
1737<li><code>msecs</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
1738<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1739<li>Returns: <a href="http.html#http_class_http_serverresponse" class="type">&#x3C;http.ServerResponse></a></li>
1740</ul>
1741<p>Sets the Socket's timeout value to <code>msecs</code>. If a callback is
1742provided, then it is added as a listener on the <code>'timeout'</code> event on
1743the response object.</p>
1744<p>If no <code>'timeout'</code> listener is added to the request, the response, or
1745the server, then sockets are destroyed when they time out. If a handler is
1746assigned to the request, the response, or the server's <code>'timeout'</code> events,
1747timed out sockets must be handled explicitly.</p>
1748<h4><code>response.socket</code><span><a class="mark" href="#http_response_socket" id="http_response_socket">#</a></span></h4>
1749<div class="api_metadata">
1750<span>Added in: v0.3.0</span>
1751</div>
1752<ul>
1753<li><a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
1754</ul>
1755<p>Reference to the underlying socket. Usually users will not want to access
1756this property. In particular, the socket will not emit <code>'readable'</code> events
1757because of how the protocol parser attaches to the socket. After
1758<code>response.end()</code>, the property is nulled.</p>
1759<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
1760<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
1761  <span class="hljs-keyword">const</span> ip = res.<span class="hljs-property">socket</span>.<span class="hljs-property">remoteAddress</span>;
1762  <span class="hljs-keyword">const</span> port = res.<span class="hljs-property">socket</span>.<span class="hljs-property">remotePort</span>;
1763  res.<span class="hljs-title function_">end</span>(<span class="hljs-string">`Your IP address is <span class="hljs-subst">${ip}</span> and your source port is <span class="hljs-subst">${port}</span>.`</span>);
1764}).<span class="hljs-title function_">listen</span>(<span class="hljs-number">3000</span>);</code></pre>
1765<p>This property is guaranteed to be an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
1766a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specified a socket
1767type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
1768<h4><code>response.statusCode</code><span><a class="mark" href="#http_response_statuscode" id="http_response_statuscode">#</a></span></h4>
1769<div class="api_metadata">
1770<span>Added in: v0.4.0</span>
1771</div>
1772<ul>
1773<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> <strong>Default:</strong> <code>200</code></li>
1774</ul>
1775<p>When using implicit headers (not calling <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a> explicitly),
1776this property controls the status code that will be sent to the client when
1777the headers get flushed.</p>
1778<pre><code class="language-js">response.<span class="hljs-property">statusCode</span> = <span class="hljs-number">404</span>;</code></pre>
1779<p>After response header was sent to the client, this property indicates the
1780status code which was sent out.</p>
1781<h4><code>response.statusMessage</code><span><a class="mark" href="#http_response_statusmessage" id="http_response_statusmessage">#</a></span></h4>
1782<div class="api_metadata">
1783<span>Added in: v0.11.8</span>
1784</div>
1785<ul>
1786<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1787</ul>
1788<p>When using implicit headers (not calling <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a> explicitly),
1789this property controls the status message that will be sent to the client when
1790the headers get flushed. If this is left as <code>undefined</code> then the standard
1791message for the status code will be used.</p>
1792<pre><code class="language-js">response.<span class="hljs-property">statusMessage</span> = <span class="hljs-string">'Not found'</span>;</code></pre>
1793<p>After response header was sent to the client, this property indicates the
1794status message which was sent out.</p>
1795<h4><code>response.uncork()</code><span><a class="mark" href="#http_response_uncork" id="http_response_uncork">#</a></span></h4>
1796<div class="api_metadata">
1797<span>Added in: v13.2.0, v12.16.0</span>
1798</div>
1799<p>See <a href="stream.html#stream_writable_uncork"><code>writable.uncork()</code></a>.</p>
1800<h4><code>response.writableEnded</code><span><a class="mark" href="#http_response_writableended" id="http_response_writableended">#</a></span></h4>
1801<div class="api_metadata">
1802<span>Added in: v12.9.0</span>
1803</div>
1804<ul>
1805<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1806</ul>
1807<p>Is <code>true</code> after <a href="#http_response_end_data_encoding_callback"><code>response.end()</code></a> has been called. This property
1808does not indicate whether the data has been flushed, for this use
1809<a href="#http_response_writablefinished"><code>response.writableFinished</code></a> instead.</p>
1810<h4><code>response.writableFinished</code><span><a class="mark" href="#http_response_writablefinished" id="http_response_writablefinished">#</a></span></h4>
1811<div class="api_metadata">
1812<span>Added in: v12.7.0</span>
1813</div>
1814<ul>
1815<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1816</ul>
1817<p>Is <code>true</code> if all data has been flushed to the underlying system, immediately
1818before the <a href="#http_event_finish"><code>'finish'</code></a> event is emitted.</p>
1819<h4><code>response.write(chunk[, encoding][, callback])</code><span><a class="mark" href="#http_response_write_chunk_encoding_callback" id="http_response_write_chunk_encoding_callback">#</a></span></h4>
1820<div class="api_metadata">
1821<span>Added in: v0.1.29</span>
1822</div>
1823<ul>
1824<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
1825<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> <strong>Default:</strong> <code>'utf8'</code></li>
1826<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1827<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1828</ul>
1829<p>If this method is called and <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a> has not been called,
1830it will switch to implicit header mode and flush the implicit headers.</p>
1831<p>This sends a chunk of the response body. This method may
1832be called multiple times to provide successive parts of the body.</p>
1833<p>In the <code>http</code> module, the response body is omitted when the
1834request is a HEAD request. Similarly, the <code>204</code> and <code>304</code> responses
1835<em>must not</em> include a message body.</p>
1836<p><code>chunk</code> can be a string or a buffer. If <code>chunk</code> is a string,
1837the second parameter specifies how to encode it into a byte stream.
1838<code>callback</code> will be called when this chunk of data is flushed.</p>
1839<p>This is the raw HTTP body and has nothing to do with higher-level multi-part
1840body encodings that may be used.</p>
1841<p>The first time <a href="#http_response_write_chunk_encoding_callback"><code>response.write()</code></a> is called, it will send the buffered
1842header information and the first chunk of the body to the client. The second
1843time <a href="#http_response_write_chunk_encoding_callback"><code>response.write()</code></a> is called, Node.js assumes data will be streamed,
1844and sends the new data separately. That is, the response is buffered up to the
1845first chunk of the body.</p>
1846<p>Returns <code>true</code> if the entire data was flushed successfully to the kernel
1847buffer. Returns <code>false</code> if all or part of the data was queued in user memory.
1848<code>'drain'</code> will be emitted when the buffer is free again.</p>
1849<h4><code>response.writeContinue()</code><span><a class="mark" href="#http_response_writecontinue" id="http_response_writecontinue">#</a></span></h4>
1850<div class="api_metadata">
1851<span>Added in: v0.3.0</span>
1852</div>
1853<p>Sends a HTTP/1.1 100 Continue message to the client, indicating that
1854the request body should be sent. See the <a href="#http_event_checkcontinue"><code>'checkContinue'</code></a> event on
1855<code>Server</code>.</p>
1856<h4><code>response.writeHead(statusCode[, statusMessage][, headers])</code><span><a class="mark" href="#http_response_writehead_statuscode_statusmessage_headers" id="http_response_writehead_statuscode_statusmessage_headers">#</a></span></h4>
1857<div class="api_metadata">
1858<details class="changelog"><summary>History</summary>
1859<table>
1860<tbody><tr><th>Version</th><th>Changes</th></tr>
1861<tr><td>v14.14.0</td>
1862<td><p>Allow passing headers as an array.</p></td></tr>
1863<tr><td>v11.10.0, v10.17.0</td>
1864<td><p>Return <code>this</code> from <code>writeHead()</code> to allow chaining with <code>end()</code>.</p></td></tr>
1865<tr><td>v5.11.0, v4.4.5</td>
1866<td><p>A <code>RangeError</code> is thrown if <code>statusCode</code> is not a number in the range <code>[100, 999]</code>.</p></td></tr>
1867<tr><td>v0.1.30</td>
1868<td><p><span>Added in: v0.1.30</span></p></td></tr>
1869</tbody></table>
1870</details>
1871</div>
1872<ul>
1873<li><code>statusCode</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
1874<li><code>statusMessage</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1875<li><code>headers</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array" class="type">&#x3C;Array></a></li>
1876<li>Returns: <a href="http.html#http_class_http_serverresponse" class="type">&#x3C;http.ServerResponse></a></li>
1877</ul>
1878<p>Sends a response header to the request. The status code is a 3-digit HTTP
1879status code, like <code>404</code>. The last argument, <code>headers</code>, are the response headers.
1880Optionally one can give a human-readable <code>statusMessage</code> as the second
1881argument.</p>
1882<p><code>headers</code> may be an <code>Array</code> where the keys and values are in the same list.
1883It is <em>not</em> a list of tuples. So, the even-numbered offsets are key values,
1884and the odd-numbered offsets are the associated values. The array is in the same
1885format as <code>request.rawHeaders</code>.</p>
1886<p>Returns a reference to the <code>ServerResponse</code>, so that calls can be chained.</p>
1887<pre><code class="language-js"><span class="hljs-keyword">const</span> body = <span class="hljs-string">'hello world'</span>;
1888response
1889  .<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, {
1890    <span class="hljs-string">'Content-Length'</span>: <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">byteLength</span>(body),
1891    <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'text/plain'</span>
1892  })
1893  .<span class="hljs-title function_">end</span>(body);</code></pre>
1894<p>This method must only be called once on a message and it must
1895be called before <a href="#http_response_end_data_encoding_callback"><code>response.end()</code></a> is called.</p>
1896<p>If <a href="#http_response_write_chunk_encoding_callback"><code>response.write()</code></a> or <a href="#http_response_end_data_encoding_callback"><code>response.end()</code></a> are called before calling
1897this, the implicit/mutable headers will be calculated and call this function.</p>
1898<p>When headers have been set with <a href="#http_response_setheader_name_value"><code>response.setHeader()</code></a>, they will be merged
1899with any headers passed to <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a>, with the headers passed
1900to <a href="#http_response_writehead_statuscode_statusmessage_headers"><code>response.writeHead()</code></a> given precedence.</p>
1901<p>If this method is called and <a href="#http_response_setheader_name_value"><code>response.setHeader()</code></a> has not been called,
1902it will directly write the supplied header values onto the network channel
1903without caching internally, and the <a href="#http_response_getheader_name"><code>response.getHeader()</code></a> on the header
1904will not yield the expected result. If progressive population of headers is
1905desired with potential future retrieval and modification, use
1906<a href="#http_response_setheader_name_value"><code>response.setHeader()</code></a> instead.</p>
1907<pre><code class="language-js"><span class="hljs-comment">// Returns content-type = text/plain</span>
1908<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
1909  res.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Content-Type'</span>, <span class="hljs-string">'text/html'</span>);
1910  res.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'X-Foo'</span>, <span class="hljs-string">'bar'</span>);
1911  res.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'text/plain'</span> });
1912  res.<span class="hljs-title function_">end</span>(<span class="hljs-string">'ok'</span>);
1913});</code></pre>
1914<p><code>Content-Length</code> is given in bytes, not characters. Use
1915<a href="buffer.html#buffer_static_method_buffer_bytelength_string_encoding"><code>Buffer.byteLength()</code></a> to determine the length of the body in bytes. Node.js
1916does not check whether <code>Content-Length</code> and the length of the body which has
1917been transmitted are equal or not.</p>
1918<p>Attempting to set a header field name or value that contains invalid characters
1919will result in a <a href="errors.html#errors_class_typeerror"><code>TypeError</code></a> being thrown.</p>
1920<h4><code>response.writeProcessing()</code><span><a class="mark" href="#http_response_writeprocessing" id="http_response_writeprocessing">#</a></span></h4>
1921<div class="api_metadata">
1922<span>Added in: v10.0.0</span>
1923</div>
1924<p>Sends a HTTP/1.1 102 Processing message to the client, indicating that
1925the request body should be sent.</p>
1926</section><section><h3>Class: <code>http.IncomingMessage</code><span><a class="mark" href="#http_class_http_incomingmessage" id="http_class_http_incomingmessage">#</a></span></h3>
1927<div class="api_metadata">
1928<details class="changelog"><summary>History</summary>
1929<table>
1930<tbody><tr><th>Version</th><th>Changes</th></tr>
1931<tr><td>v13.1.0, v12.16.0</td>
1932<td><p>The <code>readableHighWaterMark</code> value mirrors that of the socket.</p></td></tr>
1933<tr><td>v0.1.17</td>
1934<td><p><span>Added in: v0.1.17</span></p></td></tr>
1935</tbody></table>
1936</details>
1937</div>
1938<ul>
1939<li>Extends: <a href="stream.html#stream_class_stream_readable" class="type">&#x3C;stream.Readable></a></li>
1940</ul>
1941<p>An <code>IncomingMessage</code> object is created by <a href="#http_class_http_server"><code>http.Server</code></a> or
1942<a href="#http_class_http_clientrequest"><code>http.ClientRequest</code></a> and passed as the first argument to the <a href="#http_event_request"><code>'request'</code></a>
1943and <a href="#http_event_response"><code>'response'</code></a> event respectively. It may be used to access response
1944status, headers and data.</p>
1945<h4>Event: <code>'aborted'</code><span><a class="mark" href="#http_event_aborted" id="http_event_aborted">#</a></span></h4>
1946<div class="api_metadata">
1947<span>Added in: v0.3.8</span>
1948</div>
1949<p>Emitted when the request has been aborted.</p>
1950<h4>Event: <code>'close'</code><span><a class="mark" href="#http_event_close_2" id="http_event_close_2">#</a></span></h4>
1951<div class="api_metadata">
1952<span>Added in: v0.4.2</span>
1953</div>
1954<p>Indicates that the underlying connection was closed.</p>
1955<h4><code>message.aborted</code><span><a class="mark" href="#http_message_aborted" id="http_message_aborted">#</a></span></h4>
1956<div class="api_metadata">
1957<span>Added in: v10.1.0</span>
1958</div>
1959<ul>
1960<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1961</ul>
1962<p>The <code>message.aborted</code> property will be <code>true</code> if the request has
1963been aborted.</p>
1964<h4><code>message.complete</code><span><a class="mark" href="#http_message_complete" id="http_message_complete">#</a></span></h4>
1965<div class="api_metadata">
1966<span>Added in: v0.3.0</span>
1967</div>
1968<ul>
1969<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1970</ul>
1971<p>The <code>message.complete</code> property will be <code>true</code> if a complete HTTP message has
1972been received and successfully parsed.</p>
1973<p>This property is particularly useful as a means of determining if a client or
1974server fully transmitted a message before a connection was terminated:</p>
1975<pre><code class="language-js"><span class="hljs-keyword">const</span> req = http.<span class="hljs-title function_">request</span>({
1976  <span class="hljs-attr">host</span>: <span class="hljs-string">'127.0.0.1'</span>,
1977  <span class="hljs-attr">port</span>: <span class="hljs-number">8080</span>,
1978  <span class="hljs-attr">method</span>: <span class="hljs-string">'POST'</span>
1979}, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
1980  res.<span class="hljs-title function_">resume</span>();
1981  res.<span class="hljs-title function_">on</span>(<span class="hljs-string">'end'</span>, <span class="hljs-function">() =></span> {
1982    <span class="hljs-keyword">if</span> (!res.<span class="hljs-property">complete</span>)
1983      <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(
1984        <span class="hljs-string">'The connection was terminated while the message was still being sent'</span>);
1985  });
1986});</code></pre>
1987<h4><code>message.destroy([error])</code><span><a class="mark" href="#http_message_destroy_error" id="http_message_destroy_error">#</a></span></h4>
1988<div class="api_metadata">
1989<details class="changelog"><summary>History</summary>
1990<table>
1991<tbody><tr><th>Version</th><th>Changes</th></tr>
1992<tr><td>v14.5.0</td>
1993<td><p>The function returns <code>this</code> for consistency with other Readable streams.</p></td></tr>
1994<tr><td>v0.3.0</td>
1995<td><p><span>Added in: v0.3.0</span></p></td></tr>
1996</tbody></table>
1997</details>
1998</div>
1999<ul>
2000<li><code>error</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a></li>
2001<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
2002</ul>
2003<p>Calls <code>destroy()</code> on the socket that received the <code>IncomingMessage</code>. If <code>error</code>
2004is provided, an <code>'error'</code> event is emitted on the socket and <code>error</code> is passed
2005as an argument to any listeners on the event.</p>
2006<h4><code>message.headers</code><span><a class="mark" href="#http_message_headers" id="http_message_headers">#</a></span></h4>
2007<div class="api_metadata">
2008<span>Added in: v0.1.5</span>
2009</div>
2010<ul>
2011<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
2012</ul>
2013<p>The request/response headers object.</p>
2014<p>Key-value pairs of header names and values. Header names are lower-cased.</p>
2015<pre><code class="language-js"><span class="hljs-comment">// Prints something like:</span>
2016<span class="hljs-comment">//</span>
2017<span class="hljs-comment">// { 'user-agent': 'curl/7.22.0',</span>
2018<span class="hljs-comment">//   host: '127.0.0.1:8000',</span>
2019<span class="hljs-comment">//   accept: '*/*' }</span>
2020<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(request.<span class="hljs-property">headers</span>);</code></pre>
2021<p>Duplicates in raw headers are handled in the following ways, depending on the
2022header name:</p>
2023<ul>
2024<li>Duplicates of <code>age</code>, <code>authorization</code>, <code>content-length</code>, <code>content-type</code>,
2025<code>etag</code>, <code>expires</code>, <code>from</code>, <code>host</code>, <code>if-modified-since</code>, <code>if-unmodified-since</code>,
2026<code>last-modified</code>, <code>location</code>, <code>max-forwards</code>, <code>proxy-authorization</code>, <code>referer</code>,
2027<code>retry-after</code>, <code>server</code>, or <code>user-agent</code> are discarded.</li>
2028<li><code>set-cookie</code> is always an array. Duplicates are added to the array.</li>
2029<li>For duplicate <code>cookie</code> headers, the values are joined together with '; '.</li>
2030<li>For all other headers, the values are joined together with ', '.</li>
2031</ul>
2032<h4><code>message.httpVersion</code><span><a class="mark" href="#http_message_httpversion" id="http_message_httpversion">#</a></span></h4>
2033<div class="api_metadata">
2034<span>Added in: v0.1.1</span>
2035</div>
2036<ul>
2037<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
2038</ul>
2039<p>In case of server request, the HTTP version sent by the client. In the case of
2040client response, the HTTP version of the connected-to server.
2041Probably either <code>'1.1'</code> or <code>'1.0'</code>.</p>
2042<p>Also <code>message.httpVersionMajor</code> is the first integer and
2043<code>message.httpVersionMinor</code> is the second.</p>
2044<h4><code>message.method</code><span><a class="mark" href="#http_message_method" id="http_message_method">#</a></span></h4>
2045<div class="api_metadata">
2046<span>Added in: v0.1.1</span>
2047</div>
2048<ul>
2049<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
2050</ul>
2051<p><strong>Only valid for request obtained from <a href="#http_class_http_server"><code>http.Server</code></a>.</strong></p>
2052<p>The request method as a string. Read only. Examples: <code>'GET'</code>, <code>'DELETE'</code>.</p>
2053<h4><code>message.rawHeaders</code><span><a class="mark" href="#http_message_rawheaders" id="http_message_rawheaders">#</a></span></h4>
2054<div class="api_metadata">
2055<span>Added in: v0.11.6</span>
2056</div>
2057<ul>
2058<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
2059</ul>
2060<p>The raw request/response headers list exactly as they were received.</p>
2061<p>The keys and values are in the same list. It is <em>not</em> a
2062list of tuples. So, the even-numbered offsets are key values, and the
2063odd-numbered offsets are the associated values.</p>
2064<p>Header names are not lowercased, and duplicates are not merged.</p>
2065<pre><code class="language-js"><span class="hljs-comment">// Prints something like:</span>
2066<span class="hljs-comment">//</span>
2067<span class="hljs-comment">// [ 'user-agent',</span>
2068<span class="hljs-comment">//   'this is invalid because there can be only one',</span>
2069<span class="hljs-comment">//   'User-Agent',</span>
2070<span class="hljs-comment">//   'curl/7.22.0',</span>
2071<span class="hljs-comment">//   'Host',</span>
2072<span class="hljs-comment">//   '127.0.0.1:8000',</span>
2073<span class="hljs-comment">//   'ACCEPT',</span>
2074<span class="hljs-comment">//   '*/*' ]</span>
2075<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(request.<span class="hljs-property">rawHeaders</span>);</code></pre>
2076<h4><code>message.rawTrailers</code><span><a class="mark" href="#http_message_rawtrailers" id="http_message_rawtrailers">#</a></span></h4>
2077<div class="api_metadata">
2078<span>Added in: v0.11.6</span>
2079</div>
2080<ul>
2081<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
2082</ul>
2083<p>The raw request/response trailer keys and values exactly as they were
2084received. Only populated at the <code>'end'</code> event.</p>
2085<h4><code>message.setTimeout(msecs[, callback])</code><span><a class="mark" href="#http_message_settimeout_msecs_callback" id="http_message_settimeout_msecs_callback">#</a></span></h4>
2086<div class="api_metadata">
2087<span>Added in: v0.5.9</span>
2088</div>
2089<ul>
2090<li><code>msecs</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
2091<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
2092<li>Returns: <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a></li>
2093</ul>
2094<p>Calls <code>message.socket.setTimeout(msecs, callback)</code>.</p>
2095<h4><code>message.socket</code><span><a class="mark" href="#http_message_socket" id="http_message_socket">#</a></span></h4>
2096<div class="api_metadata">
2097<span>Added in: v0.3.0</span>
2098</div>
2099<ul>
2100<li><a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
2101</ul>
2102<p>The <a href="net.html#net_class_net_socket"><code>net.Socket</code></a> object associated with the connection.</p>
2103<p>With HTTPS support, use <a href="tls.html#tls_tlssocket_getpeercertificate_detailed"><code>request.socket.getPeerCertificate()</code></a> to obtain the
2104client's authentication details.</p>
2105<p>This property is guaranteed to be an instance of the <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> class,
2106a subclass of <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>, unless the user specified a socket
2107type other than <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a>.</p>
2108<h4><code>message.statusCode</code><span><a class="mark" href="#http_message_statuscode" id="http_message_statuscode">#</a></span></h4>
2109<div class="api_metadata">
2110<span>Added in: v0.1.1</span>
2111</div>
2112<ul>
2113<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
2114</ul>
2115<p><strong>Only valid for response obtained from <a href="#http_class_http_clientrequest"><code>http.ClientRequest</code></a>.</strong></p>
2116<p>The 3-digit HTTP response status code. E.G. <code>404</code>.</p>
2117<h4><code>message.statusMessage</code><span><a class="mark" href="#http_message_statusmessage" id="http_message_statusmessage">#</a></span></h4>
2118<div class="api_metadata">
2119<span>Added in: v0.11.10</span>
2120</div>
2121<ul>
2122<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
2123</ul>
2124<p><strong>Only valid for response obtained from <a href="#http_class_http_clientrequest"><code>http.ClientRequest</code></a>.</strong></p>
2125<p>The HTTP response status message (reason phrase). E.G. <code>OK</code> or <code>Internal Server Error</code>.</p>
2126<h4><code>message.trailers</code><span><a class="mark" href="#http_message_trailers" id="http_message_trailers">#</a></span></h4>
2127<div class="api_metadata">
2128<span>Added in: v0.3.0</span>
2129</div>
2130<ul>
2131<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
2132</ul>
2133<p>The request/response trailers object. Only populated at the <code>'end'</code> event.</p>
2134<h4><code>message.url</code><span><a class="mark" href="#http_message_url" id="http_message_url">#</a></span></h4>
2135<div class="api_metadata">
2136<span>Added in: v0.1.90</span>
2137</div>
2138<ul>
2139<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
2140</ul>
2141<p><strong>Only valid for request obtained from <a href="#http_class_http_server"><code>http.Server</code></a>.</strong></p>
2142<p>Request URL string. This contains only the URL that is present in the actual
2143HTTP request. Take the following request:</p>
2144<pre><code class="language-http"><span class="hljs-keyword">GET</span> <span class="hljs-string">/status?name=ryan</span> <span class="hljs-meta">HTTP/1.1</span>
2145<span class="hljs-attribute">Accept</span><span class="hljs-punctuation">: </span>text/plain</code></pre>
2146<p>To parse the URL into its parts:</p>
2147<pre><code class="language-js"><span class="hljs-keyword">new</span> <span class="hljs-title function_">URL</span>(request.<span class="hljs-property">url</span>, <span class="hljs-string">`http://<span class="hljs-subst">${request.headers.host}</span>`</span>);</code></pre>
2148<p>When <code>request.url</code> is <code>'/status?name=ryan'</code> and
2149<code>request.headers.host</code> is <code>'localhost:3000'</code>:</p>
2150<pre><code class="language-console"><span class="hljs-meta">$ </span><span class="language-bash">node</span>
2151<span class="hljs-meta">> </span><span class="language-bash">new URL(request.url, `http://<span class="hljs-variable">${request.headers.host}</span>`)</span>
2152URL {
2153  href: 'http://localhost:3000/status?name=ryan',
2154  origin: 'http://localhost:3000',
2155  protocol: 'http:',
2156  username: '',
2157  password: '',
2158  host: 'localhost:3000',
2159  hostname: 'localhost',
2160  port: '3000',
2161  pathname: '/status',
2162  search: '?name=ryan',
2163  searchParams: URLSearchParams { 'name' => 'ryan' },
2164  hash: ''
2165}</code></pre>
2166</section><section><h3>Class: <code>http.OutgoingMessage</code><span><a class="mark" href="#http_class_http_outgoingmessage" id="http_class_http_outgoingmessage">#</a></span></h3>
2167<div class="api_metadata">
2168<span>Added in: v0.1.17</span>
2169</div>
2170<ul>
2171<li>Extends: <a href="stream.html#stream_stream" class="type">&#x3C;Stream></a></li>
2172</ul>
2173<p>This class serves as the parent class of <a href="#http_class_http_clientrequest"><code>http.ClientRequest</code></a>
2174and <a href="#http_class_http_serverresponse"><code>http.ServerResponse</code></a>. It is an abstract of outgoing message from
2175the perspective of the participants of HTTP transaction.</p>
2176<h4>Event: <code>drain</code><span><a class="mark" href="#http_event_drain" id="http_event_drain">#</a></span></h4>
2177<div class="api_metadata">
2178<span>Added in: v0.3.6</span>
2179</div>
2180<p>Emitted when the buffer of the message is free again.</p>
2181<h4>Event: <code>finish</code><span><a class="mark" href="#http_event_finish_1" id="http_event_finish_1">#</a></span></h4>
2182<div class="api_metadata">
2183<span>Added in: v0.1.17</span>
2184</div>
2185<p>Emitted when the transmission is finished successfully.</p>
2186<h4>Event: <code>prefinish</code><span><a class="mark" href="#http_event_prefinish" id="http_event_prefinish">#</a></span></h4>
2187<div class="api_metadata">
2188<span>Added in: v0.11.6</span>
2189</div>
2190<p>Emitted when <code>outgoingMessage.end</code> was called.
2191When the event is emitted, all data has been processed but not necessarily
2192completely flushed.</p>
2193<h4><code>outgoingMessage.addTrailers(headers)</code><span><a class="mark" href="#http_outgoingmessage_addtrailers_headers" id="http_outgoingmessage_addtrailers_headers">#</a></span></h4>
2194<div class="api_metadata">
2195<span>Added in: v0.3.0</span>
2196</div>
2197<ul>
2198<li><code>headers</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
2199</ul>
2200<p>Adds HTTP trailers (headers but at the end of the message) to the message.</p>
2201<p>Trailers are <strong>only</strong> be emitted if the message is chunked encoded. If not,
2202the trailer will be silently discarded.</p>
2203<p>HTTP requires the  <code>Trailer</code> header to be sent to emit trailers,
2204with a list of header fields in its value, e.g.</p>
2205<pre><code class="language-js">message.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'text/plain'</span>,
2206                         <span class="hljs-string">'Trailer'</span>: <span class="hljs-string">'Content-MD5'</span> });
2207message.<span class="hljs-title function_">write</span>(fileData);
2208message.<span class="hljs-title function_">addTrailers</span>({ <span class="hljs-string">'Content-MD5'</span>: <span class="hljs-string">'7895bf4b8828b55ceaf47747b4bca667'</span> });
2209message.<span class="hljs-title function_">end</span>();</code></pre>
2210<p>Attempting to set a header field name or value that contains invalid characters
2211will result in a <code>TypeError</code> being thrown.</p>
2212<h4><code>outgoingMessage.connection</code><span><a class="mark" href="#http_outgoingmessage_connection" id="http_outgoingmessage_connection">#</a></span></h4>
2213<div class="api_metadata">
2214<span>Added in: v0.3.0</span><span>Deprecated since: v14.17.1</span>
2215</div>
2216<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated: Use <a href="#http_outgoingmessage_socket"><code>outgoingMessage.socket</code></a> instead.</div><p></p>
2217<p>Aliases of <code>outgoingMessage.socket</code></p>
2218<h4><code>outgoingMessage.cork()</code><span><a class="mark" href="#http_outgoingmessage_cork" id="http_outgoingmessage_cork">#</a></span></h4>
2219<div class="api_metadata">
2220<span>Added in: v14.0.0</span>
2221</div>
2222<p>See <a href="stream.html#stream_writable_cork"><code>writable.cork()</code></a>.</p>
2223<h4><code>outgoingMessage.destroy([error])</code><span><a class="mark" href="#http_outgoingmessage_destroy_error" id="http_outgoingmessage_destroy_error">#</a></span></h4>
2224<div class="api_metadata">
2225<span>Added in: v0.3.0</span>
2226</div>
2227<ul>
2228<li><code>error</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a> Optional, an error to emit with <code>error</code> event</li>
2229<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
2230</ul>
2231<p>Destroys the message. Once a socket is associated with the message
2232and is connected, that socket will be destroyed as well.</p>
2233<h4><code>outgoingMessage.end(chunk[, encoding][, callback])</code><span><a class="mark" href="#http_outgoingmessage_end_chunk_encoding_callback" id="http_outgoingmessage_end_chunk_encoding_callback">#</a></span></h4>
2234<div class="api_metadata">
2235<details class="changelog"><summary>History</summary>
2236<table>
2237<tbody><tr><th>Version</th><th>Changes</th></tr>
2238<tr><td>v0.11.6</td>
2239<td><p>add <code>callback</code> argument.</p></td></tr>
2240<tr><td>v0.1.90</td>
2241<td><p><span>Added in: v0.1.90</span></p></td></tr>
2242</tbody></table>
2243</details>
2244</div>
2245<ul>
2246<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
2247<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Optional, <strong>Default</strong>: <code>utf-8</code></li>
2248<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Optional</li>
2249<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
2250</ul>
2251<p>Finishes the outgoing message. If any parts of the body are unsent, it will
2252flush them to the underlying system. If the message is chunked, it will
2253send the terminating chunk <code>0\r\n\r\n</code>, and send the trailer (if any).</p>
2254<p>If <code>chunk</code> is specified, it is equivalent to call
2255<code>outgoingMessage.write(chunk, encoding)</code>, followed by
2256<code>outgoingMessage.end(callback)</code>.</p>
2257<p>If <code>callback</code> is provided, it will be called when the message is finished.
2258(equivalent to the callback to event <code>finish</code>)</p>
2259<h4><code>outgoingMessage.flushHeaders()</code><span><a class="mark" href="#http_outgoingmessage_flushheaders" id="http_outgoingmessage_flushheaders">#</a></span></h4>
2260<div class="api_metadata">
2261<span>Added in: v1.6.0</span>
2262</div>
2263<p>Compulsorily flushes the message headers</p>
2264<p>For efficiency reason, Node.js normally buffers the message headers
2265until <code>outgoingMessage.end()</code> is called or the first chunk of message data
2266is written. It then tries to pack the headers and data into a single TCP
2267packet.</p>
2268<p>It is usually desired (it saves a TCP round-trip), but not when the first
2269data is not sent until possibly much later. <code>outgoingMessage.flushHeaders()</code>
2270bypasses the optimization and kickstarts the request.</p>
2271<h4><code>outgoingMessage.getHeader(name)</code><span><a class="mark" href="#http_outgoingmessage_getheader_name" id="http_outgoingmessage_getheader_name">#</a></span></h4>
2272<div class="api_metadata">
2273<span>Added in: v0.4.0</span>
2274</div>
2275<ul>
2276<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Name of header</li>
2277<li>Returns <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Undefined_type" class="type">&#x3C;undefined></a></li>
2278</ul>
2279<p>Gets the value of HTTP header with the given name. If such a name doesn't
2280exist in message, it will be <code>undefined</code>.</p>
2281<h4><code>outgoingMessage.getHeaderNames()</code><span><a class="mark" href="#http_outgoingmessage_getheadernames" id="http_outgoingmessage_getheadernames">#</a></span></h4>
2282<div class="api_metadata">
2283<span>Added in: v8.0.0</span>
2284</div>
2285<ul>
2286<li>Returns <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
2287</ul>
2288<p>Returns an array of names of headers of the outgoing outgoingMessage. All
2289names are lowercase.</p>
2290<h4><code>outgoingMessage.getHeaders()</code><span><a class="mark" href="#http_outgoingmessage_getheaders" id="http_outgoingmessage_getheaders">#</a></span></h4>
2291<div class="api_metadata">
2292<span>Added in: v8.0.0</span>
2293</div>
2294<ul>
2295<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
2296</ul>
2297<p>Returns a shallow copy of the current outgoing headers. Since a shallow
2298copy is used, array values may be mutated without additional calls to
2299various header-related HTTP module methods. The keys of the returned
2300object are the header names and the values are the respective header
2301values. All header names are lowercase.</p>
2302<p>The object returned by the <code>outgoingMessage.getHeaders()</code> method does
2303not prototypically inherit from the JavaScript Object. This means that
2304typical Object methods such as <code>obj.toString()</code>, <code>obj.hasOwnProperty()</code>,
2305and others are not defined and will not work.</p>
2306<pre><code class="language-js">outgoingMessage.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Foo'</span>, <span class="hljs-string">'bar'</span>);
2307outgoingMessage.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Set-Cookie'</span>, [<span class="hljs-string">'foo=bar'</span>, <span class="hljs-string">'bar=baz'</span>]);
2308
2309<span class="hljs-keyword">const</span> headers = outgoingMessage.<span class="hljs-title function_">getHeaders</span>();
2310<span class="hljs-comment">// headers === { foo: 'bar', 'set-cookie': ['foo=bar', 'bar=baz'] }</span></code></pre>
2311<h4><code>outgoingMessage.hasHeader(name)</code><span><a class="mark" href="#http_outgoingmessage_hasheader_name" id="http_outgoingmessage_hasheader_name">#</a></span></h4>
2312<div class="api_metadata">
2313<span>Added in: v8.0.0</span>
2314</div>
2315<ul>
2316<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
2317<li>Returns <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
2318</ul>
2319<p>Returns <code>true</code> if the header identified by <code>name</code> is currently set in the
2320outgoing headers. The header name is case-insensitive.</p>
2321<pre><code class="language-js"><span class="hljs-keyword">const</span> hasContentType = outgoingMessage.<span class="hljs-title function_">hasHeader</span>(<span class="hljs-string">'content-type'</span>);</code></pre>
2322<h4><code>outgoingMessage.headersSent</code><span><a class="mark" href="#http_outgoingmessage_headerssent" id="http_outgoingmessage_headerssent">#</a></span></h4>
2323<div class="api_metadata">
2324<span>Added in: v0.9.3</span>
2325</div>
2326<ul>
2327<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
2328</ul>
2329<p>Read-only. <code>true</code> if the headers were sent, otherwise <code>false</code>.</p>
2330<h4><code>outgoingMessage.pipe()</code><span><a class="mark" href="#http_outgoingmessage_pipe" id="http_outgoingmessage_pipe">#</a></span></h4>
2331<div class="api_metadata">
2332<span>Added in: v9.0.0</span>
2333</div>
2334<p>Overrides the pipe method of legacy <code>Stream</code> which is the parent class of
2335<code>http.outgoingMessage</code>.</p>
2336<p>Since <code>OutgoingMessage</code> should be a write-only stream,
2337call this function will throw an <code>Error</code>. Thus, it disabled the pipe method
2338it inherits from <code>Stream</code>.</p>
2339<p>The User should not call this function directly.</p>
2340<h4><code>outgoingMessage.removeHeader()</code><span><a class="mark" href="#http_outgoingmessage_removeheader" id="http_outgoingmessage_removeheader">#</a></span></h4>
2341<div class="api_metadata">
2342<span>Added in: v0.4.0</span>
2343</div>
2344<p>Removes a header that is queued for implicit sending.</p>
2345<pre><code class="language-js">outgoingMessage.<span class="hljs-title function_">removeHeader</span>(<span class="hljs-string">'Content-Encoding'</span>);</code></pre>
2346<h4><code>outgoingMessage.setHeader(name, value)</code><span><a class="mark" href="#http_outgoingmessage_setheader_name_value" id="http_outgoingmessage_setheader_name_value">#</a></span></h4>
2347<div class="api_metadata">
2348<span>Added in: v0.4.0</span>
2349</div>
2350<ul>
2351<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Header name</li>
2352<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Header value</li>
2353<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
2354</ul>
2355<p>Sets a single header value for the header object.</p>
2356<h4><code>outgoingMessage.setTimeout(msesc[, callback])</code><span><a class="mark" href="#http_outgoingmessage_settimeout_msesc_callback" id="http_outgoingmessage_settimeout_msesc_callback">#</a></span></h4>
2357<div class="api_metadata">
2358<span>Added in: v0.9.12</span>
2359</div>
2360<ul>
2361<li><code>msesc</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
2362<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Optional function to be called when a timeout</li>
2363</ul>
2364<p>occurs, Same as binding to the <code>timeout</code> event.</p>
2365<ul>
2366<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a></li>
2367</ul>
2368<p>Once a socket is associated with the message and is connected,
2369<a href="net.html#net_socket_settimeout_timeout_callback"><code>socket.setTimeout()</code></a> will be called with <code>msecs</code> as the first parameter.</p>
2370<h4><code>outgoingMessage.socket</code><span><a class="mark" href="#http_outgoingmessage_socket" id="http_outgoingmessage_socket">#</a></span></h4>
2371<div class="api_metadata">
2372<span>Added in: v0.3.0</span>
2373</div>
2374<ul>
2375<li><a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
2376</ul>
2377<p>Reference to the underlying socket. Usually, users will not want to access
2378this property.</p>
2379<p>After calling <code>outgoingMessage.end()</code>, this property will be nulled.</p>
2380<h4><code>outgoingMessage.uncork()</code><span><a class="mark" href="#http_outgoingmessage_uncork" id="http_outgoingmessage_uncork">#</a></span></h4>
2381<div class="api_metadata">
2382<span>Added in: v14.0.0</span>
2383</div>
2384<p>See <a href="stream.html#stream_writable_uncork"><code>writable.uncork()</code></a></p>
2385<h4><code>outgoingMessage.writableCorked</code><span><a class="mark" href="#http_outgoingmessage_writablecorked" id="http_outgoingmessage_writablecorked">#</a></span></h4>
2386<div class="api_metadata">
2387<span>Added in: v14.0.0</span>
2388</div>
2389<ul>
2390<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
2391</ul>
2392<p>This <code>outgoingMessage.writableCorked</code> will return the time how many
2393<code>outgoingMessage.cork()</code> have been called.</p>
2394<h4><code>outgoingMessage.writableEnded</code><span><a class="mark" href="#http_outgoingmessage_writableended" id="http_outgoingmessage_writableended">#</a></span></h4>
2395<div class="api_metadata">
2396<span>Added in: v13.0.0</span>
2397</div>
2398<ul>
2399<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
2400</ul>
2401<p>Readonly, <code>true</code> if <code>outgoingMessage.end()</code> has been called. Noted that
2402this property does not reflect whether the data has been flush. For that
2403purpose, use <code>message.writableFinished</code> instead.</p>
2404<h4><code>outgoingMessage.writableFinished</code><span><a class="mark" href="#http_outgoingmessage_writablefinished" id="http_outgoingmessage_writablefinished">#</a></span></h4>
2405<div class="api_metadata">
2406<span>Added in: v13.0.0</span>
2407</div>
2408<ul>
2409<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
2410</ul>
2411<p>Readonly. <code>true</code> if all data has been flushed to the underlying system.</p>
2412<h4><code>outgoingMessage.writableHighWaterMark</code><span><a class="mark" href="#http_outgoingmessage_writablehighwatermark" id="http_outgoingmessage_writablehighwatermark">#</a></span></h4>
2413<div class="api_metadata">
2414<span>Added in: v13.0.0</span>
2415</div>
2416<ul>
2417<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
2418</ul>
2419<p>This <code>outgoingMessage.writableHighWaterMark</code> will be the <code>highWaterMark</code> of
2420underlying socket if socket exists. Else, it would be the default
2421<code>highWaterMark</code>.</p>
2422<p><code>highWaterMark</code> is the maximum amount of data that can be potentially
2423buffered by the socket.</p>
2424<h4><code>outgoingMessage.writableLength</code><span><a class="mark" href="#http_outgoingmessage_writablelength" id="http_outgoingmessage_writablelength">#</a></span></h4>
2425<div class="api_metadata">
2426<span>Added in: v13.0.0</span>
2427</div>
2428<ul>
2429<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
2430</ul>
2431<p>Readonly, This <code>outgoingMessage.writableLength</code> contains the number of
2432bytes (or objects) in the buffer ready to send.</p>
2433<h4><code>outgoingMessage.writableObjectMode</code><span><a class="mark" href="#http_outgoingmessage_writableobjectmode" id="http_outgoingmessage_writableobjectmode">#</a></span></h4>
2434<div class="api_metadata">
2435<span>Added in: v13.0.0</span>
2436</div>
2437<ul>
2438<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
2439</ul>
2440<p>Readonly, always returns <code>false</code>.</p>
2441<h4><code>outgoingMessage.write(chunk[, encoding][, callback])</code><span><a class="mark" href="#http_outgoingmessage_write_chunk_encoding_callback" id="http_outgoingmessage_write_chunk_encoding_callback">#</a></span></h4>
2442<div class="api_metadata">
2443<details class="changelog"><summary>History</summary>
2444<table>
2445<tbody><tr><th>Version</th><th>Changes</th></tr>
2446<tr><td>v0.11.6</td>
2447<td><p>add <code>callback</code> argument.</p></td></tr>
2448<tr><td>v0.1.29</td>
2449<td><p><span>Added in: v0.1.29</span></p></td></tr>
2450</tbody></table>
2451</details>
2452</div>
2453<ul>
2454<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
2455<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> <strong>Default</strong>: <code>utf-8</code></li>
2456<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
2457<li>Returns <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
2458</ul>
2459<p>If this method is called and the header is not sent, it will call
2460<code>this._implicitHeader</code> to flush implicit header.
2461If the message should not have a body (indicated by <code>this._hasBody</code>),
2462the call is ignored and <code>chunk</code> will not be sent. It could be useful
2463when handling a particular message which must not include a body.
2464e.g. response to <code>HEAD</code> request, <code>204</code> and <code>304</code> response.</p>
2465<p><code>chunk</code> can be a string or a buffer. When <code>chunk</code> is a string, the
2466<code>encoding</code> parameter specifies how to encode <code>chunk</code> into a byte stream.
2467<code>callback</code> will be called when the <code>chunk</code> is flushed.</p>
2468<p>If the message is transferred in chucked encoding
2469(indicated by <code>this.chunkedEncoding</code>), <code>chunk</code> will be flushed as
2470one chunk among a stream of chunks. Otherwise, it will be flushed as the
2471body of message.</p>
2472<p>This method handles the raw body of the HTTP message and has nothing to do
2473with higher-level multi-part body encodings that may be used.</p>
2474<p>If it is the first call to this method of a message, it will send the
2475buffered header first, then flush the <code>chunk</code> as described above.</p>
2476<p>The second and successive calls to this method will assume the data
2477will be streamed and send the new data separately. It means that the response
2478is buffered up to the first chunk of the body.</p>
2479<p>Returns <code>true</code> if the entire data was flushed successfully to the kernel
2480buffer. Returns <code>false</code> if all or part of the data was queued in the user
2481memory. Event <code>drain</code> will be emitted when the buffer is free again.</p>
2482</section><section><h3><code>http.METHODS</code><span><a class="mark" href="#http_http_methods" id="http_http_methods">#</a></span></h3>
2483<div class="api_metadata">
2484<span>Added in: v0.11.8</span>
2485</div>
2486<ul>
2487<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
2488</ul>
2489<p>A list of the HTTP methods that are supported by the parser.</p>
2490</section><section><h3><code>http.STATUS_CODES</code><span><a class="mark" href="#http_http_status_codes" id="http_http_status_codes">#</a></span></h3>
2491<div class="api_metadata">
2492<span>Added in: v0.1.22</span>
2493</div>
2494<ul>
2495<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
2496</ul>
2497<p>A collection of all the standard HTTP response status codes, and the
2498short description of each. For example, <code>http.STATUS_CODES[404] === 'Not Found'</code>.</p>
2499</section><section><h3><code>http.createServer([options][, requestListener])</code><span><a class="mark" href="#http_http_createserver_options_requestlistener" id="http_http_createserver_options_requestlistener">#</a></span></h3>
2500<div class="api_metadata">
2501<details class="changelog"><summary>History</summary>
2502<table>
2503<tbody><tr><th>Version</th><th>Changes</th></tr>
2504<tr><td>v13.3.0</td>
2505<td><p>The <code>maxHeaderSize</code> option is supported now.</p></td></tr>
2506<tr><td>v13.8.0, v12.15.0, v10.19.0</td>
2507<td><p>The <code>insecureHTTPParser</code> option is supported now.</p></td></tr>
2508<tr><td>v9.6.0, v8.12.0</td>
2509<td><p>The <code>options</code> argument is supported now.</p></td></tr>
2510<tr><td>v0.1.13</td>
2511<td><p><span>Added in: v0.1.13</span></p></td></tr>
2512</tbody></table>
2513</details>
2514</div>
2515<ul>
2516<li>
2517<p><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></p>
2518<ul>
2519<li><code>IncomingMessage</code> <a href="http.html#http_class_http_incomingmessage" class="type">&#x3C;http.IncomingMessage></a> Specifies the <code>IncomingMessage</code>
2520class to be used. Useful for extending the original <code>IncomingMessage</code>.
2521<strong>Default:</strong> <code>IncomingMessage</code>.</li>
2522<li><code>ServerResponse</code> <a href="http.html#http_class_http_serverresponse" class="type">&#x3C;http.ServerResponse></a> Specifies the <code>ServerResponse</code> class
2523to be used. Useful for extending the original <code>ServerResponse</code>. <strong>Default:</strong>
2524<code>ServerResponse</code>.</li>
2525<li><code>insecureHTTPParser</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Use an insecure HTTP parser that accepts
2526invalid HTTP headers when <code>true</code>. Using the insecure parser should be
2527avoided. See <a href="cli.html#cli_insecure_http_parser"><code>--insecure-http-parser</code></a> for more information.
2528<strong>Default:</strong> <code>false</code></li>
2529<li><code>maxHeaderSize</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Optionally overrides the value of
2530<a href="cli.html#cli_max_http_header_size_size"><code>--max-http-header-size</code></a> for requests received by this server, i.e.
2531the maximum length of request headers in bytes.
2532<strong>Default:</strong> 16384 (16KB).</li>
2533</ul>
2534</li>
2535<li>
2536<p><code>requestListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></p>
2537</li>
2538<li>
2539<p>Returns: <a href="http.html#http_class_http_server" class="type">&#x3C;http.Server></a></p>
2540</li>
2541</ul>
2542<p>Returns a new instance of <a href="#http_class_http_server"><code>http.Server</code></a>.</p>
2543<p>The <code>requestListener</code> is a function which is automatically
2544added to the <a href="#http_event_request"><code>'request'</code></a> event.</p>
2545
2546<pre><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><pre><code class="language-js cjs"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
2547
2548<span class="hljs-comment">// Create a local server to receive data from</span>
2549<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
2550  res.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'application/json'</span> });
2551  res.<span class="hljs-title function_">end</span>(<span class="hljs-variable constant_">JSON</span>.<span class="hljs-title function_">stringify</span>({
2552    <span class="hljs-attr">data</span>: <span class="hljs-string">'Hello World!'</span>
2553  }));
2554});
2555
2556server.<span class="hljs-title function_">listen</span>(<span class="hljs-number">8000</span>);</code></pre><code class="language-js cjs"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
2557
2558<span class="hljs-comment">// Create a local server to receive data from</span>
2559<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>();
2560
2561<span class="hljs-comment">// Listen to the request event</span>
2562server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'request'</span>, <span class="hljs-function">(<span class="hljs-params">request, res</span>) =></span> {
2563  res.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'application/json'</span> });
2564  res.<span class="hljs-title function_">end</span>(<span class="hljs-variable constant_">JSON</span>.<span class="hljs-title function_">stringify</span>({
2565    <span class="hljs-attr">data</span>: <span class="hljs-string">'Hello World!'</span>
2566  }));
2567});
2568
2569server.<span class="hljs-title function_">listen</span>(<span class="hljs-number">8000</span>);</code></pre>
2570</section><section><h3><code>http.get(options[, callback])</code><span><a class="mark" href="#http_http_get_options_callback" id="http_http_get_options_callback">#</a></span></h3>
2571</section><section><h3><code>http.get(url[, options][, callback])</code><span><a class="mark" href="#http_http_get_url_options_callback" id="http_http_get_url_options_callback">#</a></span></h3>
2572<div class="api_metadata">
2573<details class="changelog"><summary>History</summary>
2574<table>
2575<tbody><tr><th>Version</th><th>Changes</th></tr>
2576<tr><td>v10.9.0</td>
2577<td><p>The <code>url</code> parameter can now be passed along with a separate <code>options</code> object.</p></td></tr>
2578<tr><td>v7.5.0</td>
2579<td><p>The <code>options</code> parameter can be a WHATWG <code>URL</code> object.</p></td></tr>
2580<tr><td>v0.3.6</td>
2581<td><p><span>Added in: v0.3.6</span></p></td></tr>
2582</tbody></table>
2583</details>
2584</div>
2585<ul>
2586<li><code>url</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="url.html#url_the_whatwg_url_api" class="type">&#x3C;URL></a></li>
2587<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> Accepts the same <code>options</code> as
2588<a href="#http_http_request_options_callback"><code>http.request()</code></a>, with the <code>method</code> always set to <code>GET</code>.
2589Properties that are inherited from the prototype are ignored.</li>
2590<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
2591<li>Returns: <a href="http.html#http_class_http_clientrequest" class="type">&#x3C;http.ClientRequest></a></li>
2592</ul>
2593<p>Since most requests are GET requests without bodies, Node.js provides this
2594convenience method. The only difference between this method and
2595<a href="#http_http_request_options_callback"><code>http.request()</code></a> is that it sets the method to GET and calls <code>req.end()</code>
2596automatically. The callback must take care to consume the response
2597data for reasons stated in <a href="#http_class_http_clientrequest"><code>http.ClientRequest</code></a> section.</p>
2598<p>The <code>callback</code> is invoked with a single argument that is an instance of
2599<a href="#http_class_http_incomingmessage"><code>http.IncomingMessage</code></a>.</p>
2600<p>JSON fetching example:</p>
2601<pre><code class="language-js">http.<span class="hljs-title function_">get</span>(<span class="hljs-string">'http://localhost:8000/'</span>, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
2602  <span class="hljs-keyword">const</span> { statusCode } = res;
2603  <span class="hljs-keyword">const</span> contentType = res.<span class="hljs-property">headers</span>[<span class="hljs-string">'content-type'</span>];
2604
2605  <span class="hljs-keyword">let</span> error;
2606  <span class="hljs-comment">// Any 2xx status code signals a successful response but</span>
2607  <span class="hljs-comment">// here we're only checking for 200.</span>
2608  <span class="hljs-keyword">if</span> (statusCode !== <span class="hljs-number">200</span>) {
2609    error = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Error</span>(<span class="hljs-string">'Request Failed.\n'</span> +
2610                      <span class="hljs-string">`Status Code: <span class="hljs-subst">${statusCode}</span>`</span>);
2611  } <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (!<span class="hljs-regexp">/^application\/json/</span>.<span class="hljs-title function_">test</span>(contentType)) {
2612    error = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Error</span>(<span class="hljs-string">'Invalid content-type.\n'</span> +
2613                      <span class="hljs-string">`Expected application/json but received <span class="hljs-subst">${contentType}</span>`</span>);
2614  }
2615  <span class="hljs-keyword">if</span> (error) {
2616    <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(error.<span class="hljs-property">message</span>);
2617    <span class="hljs-comment">// Consume response data to free up memory</span>
2618    res.<span class="hljs-title function_">resume</span>();
2619    <span class="hljs-keyword">return</span>;
2620  }
2621
2622  res.<span class="hljs-title function_">setEncoding</span>(<span class="hljs-string">'utf8'</span>);
2623  <span class="hljs-keyword">let</span> rawData = <span class="hljs-string">''</span>;
2624  res.<span class="hljs-title function_">on</span>(<span class="hljs-string">'data'</span>, <span class="hljs-function">(<span class="hljs-params">chunk</span>) =></span> { rawData += chunk; });
2625  res.<span class="hljs-title function_">on</span>(<span class="hljs-string">'end'</span>, <span class="hljs-function">() =></span> {
2626    <span class="hljs-keyword">try</span> {
2627      <span class="hljs-keyword">const</span> parsedData = <span class="hljs-variable constant_">JSON</span>.<span class="hljs-title function_">parse</span>(rawData);
2628      <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(parsedData);
2629    } <span class="hljs-keyword">catch</span> (e) {
2630      <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(e.<span class="hljs-property">message</span>);
2631    }
2632  });
2633}).<span class="hljs-title function_">on</span>(<span class="hljs-string">'error'</span>, <span class="hljs-function">(<span class="hljs-params">e</span>) =></span> {
2634  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">`Got error: <span class="hljs-subst">${e.message}</span>`</span>);
2635});
2636
2637<span class="hljs-comment">// Create a local server to receive data from</span>
2638<span class="hljs-keyword">const</span> server = http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">req, res</span>) =></span> {
2639  res.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'application/json'</span> });
2640  res.<span class="hljs-title function_">end</span>(<span class="hljs-variable constant_">JSON</span>.<span class="hljs-title function_">stringify</span>({
2641    <span class="hljs-attr">data</span>: <span class="hljs-string">'Hello World!'</span>
2642  }));
2643});
2644
2645server.<span class="hljs-title function_">listen</span>(<span class="hljs-number">8000</span>);</code></pre>
2646</section><section><h3><code>http.globalAgent</code><span><a class="mark" href="#http_http_globalagent" id="http_http_globalagent">#</a></span></h3>
2647<div class="api_metadata">
2648<span>Added in: v0.5.9</span>
2649</div>
2650<ul>
2651<li><a href="http.html#http_class_http_agent" class="type">&#x3C;http.Agent></a></li>
2652</ul>
2653<p>Global instance of <code>Agent</code> which is used as the default for all HTTP client
2654requests.</p>
2655</section><section><h3><code>http.maxHeaderSize</code><span><a class="mark" href="#http_http_maxheadersize" id="http_http_maxheadersize">#</a></span></h3>
2656<div class="api_metadata">
2657<span>Added in: v11.6.0, v10.15.0</span>
2658</div>
2659<ul>
2660<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
2661</ul>
2662<p>Read-only property specifying the maximum allowed size of HTTP headers in bytes.
2663Defaults to 8KB. Configurable using the <a href="cli.html#cli_max_http_header_size_size"><code>--max-http-header-size</code></a> CLI option.</p>
2664<p>This can be overridden for servers and client requests by passing the
2665<code>maxHeaderSize</code> option.</p>
2666</section><section><h3><code>http.request(options[, callback])</code><span><a class="mark" href="#http_http_request_options_callback" id="http_http_request_options_callback">#</a></span></h3>
2667</section><section><h3><code>http.request(url[, options][, callback])</code><span><a class="mark" href="#http_http_request_url_options_callback" id="http_http_request_url_options_callback">#</a></span></h3>
2668<div class="api_metadata">
2669<details class="changelog"><summary>History</summary>
2670<table>
2671<tbody><tr><th>Version</th><th>Changes</th></tr>
2672<tr><td>v14.18.0</td>
2673<td><p>When using a <code>URL</code> object parsed username and password will now be properly URI decoded.</p></td></tr>
2674<tr><td>v14.17.0</td>
2675<td><p>It is possible to abort a request with an AbortSignal.</p></td></tr>
2676<tr><td>v13.3.0</td>
2677<td><p>The <code>maxHeaderSize</code> option is supported now.</p></td></tr>
2678<tr><td>v13.8.0, v12.15.0, v10.19.0</td>
2679<td><p>The <code>insecureHTTPParser</code> option is supported now.</p></td></tr>
2680<tr><td>v10.9.0</td>
2681<td><p>The <code>url</code> parameter can now be passed along with a separate <code>options</code> object.</p></td></tr>
2682<tr><td>v7.5.0</td>
2683<td><p>The <code>options</code> parameter can be a WHATWG <code>URL</code> object.</p></td></tr>
2684<tr><td>v0.3.6</td>
2685<td><p><span>Added in: v0.3.6</span></p></td></tr>
2686</tbody></table>
2687</details>
2688</div>
2689<ul>
2690<li><code>url</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="url.html#url_the_whatwg_url_api" class="type">&#x3C;URL></a></li>
2691<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a>
2692<ul>
2693<li><code>agent</code> <a href="http.html#http_class_http_agent" class="type">&#x3C;http.Agent></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Controls <a href="#http_class_http_agent"><code>Agent</code></a> behavior. Possible
2694values:
2695<ul>
2696<li><code>undefined</code> (default): use <a href="#http_http_globalagent"><code>http.globalAgent</code></a> for this host and port.</li>
2697<li><code>Agent</code> object: explicitly use the passed in <code>Agent</code>.</li>
2698<li><code>false</code>: causes a new <code>Agent</code> with default values to be used.</li>
2699</ul>
2700</li>
2701<li><code>auth</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Basic authentication i.e. <code>'user:password'</code> to compute an
2702Authorization header.</li>
2703<li><code>createConnection</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> A function that produces a socket/stream to
2704use for the request when the <code>agent</code> option is not used. This can be used to
2705avoid creating a custom <code>Agent</code> class just to override the default
2706<code>createConnection</code> function. See <a href="#http_agent_createconnection_options_callback"><code>agent.createConnection()</code></a> for more
2707details. Any <a href="stream.html#stream_class_stream_duplex"><code>Duplex</code></a> stream is a valid return value.</li>
2708<li><code>defaultPort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Default port for the protocol. <strong>Default:</strong>
2709<code>agent.defaultPort</code> if an <code>Agent</code> is used, else <code>undefined</code>.</li>
2710<li><code>family</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> IP address family to use when resolving <code>host</code> or
2711<code>hostname</code>. Valid values are <code>4</code> or <code>6</code>. When unspecified, both IP v4 and
2712v6 will be used.</li>
2713<li><code>headers</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> An object containing request headers.</li>
2714<li><code>hints</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Optional <a href="dns.html#dns_supported_getaddrinfo_flags"><code>dns.lookup()</code> hints</a>.</li>
2715<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> A domain name or IP address of the server to issue the
2716request to. <strong>Default:</strong> <code>'localhost'</code>.</li>
2717<li><code>hostname</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Alias for <code>host</code>. To support <a href="url.html#url_url_parse_urlstring_parsequerystring_slashesdenotehost"><code>url.parse()</code></a>,
2718<code>hostname</code> will be used if both <code>host</code> and <code>hostname</code> are specified.</li>
2719<li><code>insecureHTTPParser</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Use an insecure HTTP parser that accepts
2720invalid HTTP headers when <code>true</code>. Using the insecure parser should be
2721avoided. See <a href="cli.html#cli_insecure_http_parser"><code>--insecure-http-parser</code></a> for more information.
2722<strong>Default:</strong> <code>false</code></li>
2723<li><code>localAddress</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Local interface to bind for network connections.</li>
2724<li><code>localPort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Local port to connect from.</li>
2725<li><code>lookup</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Custom lookup function. <strong>Default:</strong> <a href="dns.html#dns_dns_lookup_hostname_options_callback"><code>dns.lookup()</code></a>.</li>
2726<li><code>maxHeaderSize</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Optionally overrides the value of
2727<a href="cli.html#cli_max_http_header_size_size"><code>--max-http-header-size</code></a> for requests received from the server, i.e.
2728the maximum length of response headers in bytes.
2729<strong>Default:</strong> 16384 (16KB).</li>
2730<li><code>method</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> A string specifying the HTTP request method. <strong>Default:</strong>
2731<code>'GET'</code>.</li>
2732<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Request path. Should include query string if any.
2733E.G. <code>'/index.html?page=12'</code>. An exception is thrown when the request path
2734contains illegal characters. Currently, only spaces are rejected but that
2735may change in the future. <strong>Default:</strong> <code>'/'</code>.</li>
2736<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Port of remote server. <strong>Default:</strong> <code>defaultPort</code> if set,
2737else <code>80</code>.</li>
2738<li><code>protocol</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Protocol to use. <strong>Default:</strong> <code>'http:'</code>.</li>
2739<li><code>setHost</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a>: Specifies whether or not to automatically add the
2740<code>Host</code> header. Defaults to <code>true</code>.</li>
2741<li><code>socketPath</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Unix Domain Socket (cannot be used if one of <code>host</code>
2742or <code>port</code> is specified, those specify a TCP Socket).</li>
2743<li><code>timeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a>: A number specifying the socket timeout in milliseconds.
2744This will set the timeout before the socket is connected.</li>
2745<li><code>signal</code> <a href="globals.html#globals_class_abortsignal" class="type">&#x3C;AbortSignal></a>: An AbortSignal that may be used to abort an ongoing
2746request.</li>
2747</ul>
2748</li>
2749<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
2750<li>Returns: <a href="http.html#http_class_http_clientrequest" class="type">&#x3C;http.ClientRequest></a></li>
2751</ul>
2752<p>Node.js maintains several connections per server to make HTTP requests.
2753This function allows one to transparently issue requests.</p>
2754<p><code>url</code> can be a string or a <a href="url.html#url_the_whatwg_url_api"><code>URL</code></a> object. If <code>url</code> is a
2755string, it is automatically parsed with <a href="url.html#url_new_url_input_base"><code>new URL()</code></a>. If it is a <a href="url.html#url_the_whatwg_url_api"><code>URL</code></a>
2756object, it will be automatically converted to an ordinary <code>options</code> object.</p>
2757<p>If both <code>url</code> and <code>options</code> are specified, the objects are merged, with the
2758<code>options</code> properties taking precedence.</p>
2759<p>The optional <code>callback</code> parameter will be added as a one-time listener for
2760the <a href="#http_event_response"><code>'response'</code></a> event.</p>
2761<p><code>http.request()</code> returns an instance of the <a href="#http_class_http_clientrequest"><code>http.ClientRequest</code></a>
2762class. The <code>ClientRequest</code> instance is a writable stream. If one needs to
2763upload a file with a POST request, then write to the <code>ClientRequest</code> object.</p>
2764<pre><code class="language-js"><span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
2765
2766<span class="hljs-keyword">const</span> postData = <span class="hljs-variable constant_">JSON</span>.<span class="hljs-title function_">stringify</span>({
2767  <span class="hljs-string">'msg'</span>: <span class="hljs-string">'Hello World!'</span>
2768});
2769
2770<span class="hljs-keyword">const</span> options = {
2771  <span class="hljs-attr">hostname</span>: <span class="hljs-string">'www.google.com'</span>,
2772  <span class="hljs-attr">port</span>: <span class="hljs-number">80</span>,
2773  <span class="hljs-attr">path</span>: <span class="hljs-string">'/upload'</span>,
2774  <span class="hljs-attr">method</span>: <span class="hljs-string">'POST'</span>,
2775  <span class="hljs-attr">headers</span>: {
2776    <span class="hljs-string">'Content-Type'</span>: <span class="hljs-string">'application/json'</span>,
2777    <span class="hljs-string">'Content-Length'</span>: <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">byteLength</span>(postData)
2778  }
2779};
2780
2781<span class="hljs-keyword">const</span> req = http.<span class="hljs-title function_">request</span>(options, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
2782  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`STATUS: <span class="hljs-subst">${res.statusCode}</span>`</span>);
2783  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`HEADERS: <span class="hljs-subst">${<span class="hljs-built_in">JSON</span>.stringify(res.headers)}</span>`</span>);
2784  res.<span class="hljs-title function_">setEncoding</span>(<span class="hljs-string">'utf8'</span>);
2785  res.<span class="hljs-title function_">on</span>(<span class="hljs-string">'data'</span>, <span class="hljs-function">(<span class="hljs-params">chunk</span>) =></span> {
2786    <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`BODY: <span class="hljs-subst">${chunk}</span>`</span>);
2787  });
2788  res.<span class="hljs-title function_">on</span>(<span class="hljs-string">'end'</span>, <span class="hljs-function">() =></span> {
2789    <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'No more data in response.'</span>);
2790  });
2791});
2792
2793req.<span class="hljs-title function_">on</span>(<span class="hljs-string">'error'</span>, <span class="hljs-function">(<span class="hljs-params">e</span>) =></span> {
2794  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">`problem with request: <span class="hljs-subst">${e.message}</span>`</span>);
2795});
2796
2797<span class="hljs-comment">// Write data to request body</span>
2798req.<span class="hljs-title function_">write</span>(postData);
2799req.<span class="hljs-title function_">end</span>();</code></pre>
2800<p>In the example <code>req.end()</code> was called. With <code>http.request()</code> one
2801must always call <code>req.end()</code> to signify the end of the request -
2802even if there is no data being written to the request body.</p>
2803<p>If any error is encountered during the request (be that with DNS resolution,
2804TCP level errors, or actual HTTP parse errors) an <code>'error'</code> event is emitted
2805on the returned request object. As with all <code>'error'</code> events, if no listeners
2806are registered the error will be thrown.</p>
2807<p>There are a few special headers that should be noted.</p>
2808<ul>
2809<li>
2810<p>Sending a 'Connection: keep-alive' will notify Node.js that the connection to
2811the server should be persisted until the next request.</p>
2812</li>
2813<li>
2814<p>Sending a 'Content-Length' header will disable the default chunked encoding.</p>
2815</li>
2816<li>
2817<p>Sending an 'Expect' header will immediately send the request headers.
2818Usually, when sending 'Expect: 100-continue', both a timeout and a listener
2819for the <code>'continue'</code> event should be set. See RFC 2616 Section 8.2.3 for more
2820information.</p>
2821</li>
2822<li>
2823<p>Sending an Authorization header will override using the <code>auth</code> option
2824to compute basic authentication.</p>
2825</li>
2826</ul>
2827<p>Example using a <a href="url.html#url_the_whatwg_url_api"><code>URL</code></a> as <code>options</code>:</p>
2828<pre><code class="language-js"><span class="hljs-keyword">const</span> options = <span class="hljs-keyword">new</span> <span class="hljs-title function_">URL</span>(<span class="hljs-string">'http://abc:xyz@example.com'</span>);
2829
2830<span class="hljs-keyword">const</span> req = http.<span class="hljs-title function_">request</span>(options, <span class="hljs-function">(<span class="hljs-params">res</span>) =></span> {
2831  <span class="hljs-comment">// ...</span>
2832});</code></pre>
2833<p>In a successful request, the following events will be emitted in the following
2834order:</p>
2835<ul>
2836<li><code>'socket'</code></li>
2837<li><code>'response'</code>
2838<ul>
2839<li><code>'data'</code> any number of times, on the <code>res</code> object
2840(<code>'data'</code> will not be emitted at all if the response body is empty, for
2841instance, in most redirects)</li>
2842<li><code>'end'</code> on the <code>res</code> object</li>
2843</ul>
2844</li>
2845<li><code>'close'</code></li>
2846</ul>
2847<p>In the case of a connection error, the following events will be emitted:</p>
2848<ul>
2849<li><code>'socket'</code></li>
2850<li><code>'error'</code></li>
2851<li><code>'close'</code></li>
2852</ul>
2853<p>In the case of a premature connection close before the response is received,
2854the following events will be emitted in the following order:</p>
2855<ul>
2856<li><code>'socket'</code></li>
2857<li><code>'error'</code> with an error with message <code>'Error: socket hang up'</code> and code
2858<code>'ECONNRESET'</code></li>
2859<li><code>'close'</code></li>
2860</ul>
2861<p>In the case of a premature connection close after the response is received,
2862the following events will be emitted in the following order:</p>
2863<ul>
2864<li><code>'socket'</code></li>
2865<li><code>'response'</code>
2866<ul>
2867<li><code>'data'</code> any number of times, on the <code>res</code> object</li>
2868</ul>
2869</li>
2870<li>(connection closed here)</li>
2871<li><code>'aborted'</code> on the <code>res</code> object</li>
2872<li><code>'close'</code></li>
2873<li><code>'close'</code> on the <code>res</code> object</li>
2874</ul>
2875<p>If <code>req.destroy()</code> is called before a socket is assigned, the following
2876events will be emitted in the following order:</p>
2877<ul>
2878<li>(<code>req.destroy()</code> called here)</li>
2879<li><code>'error'</code> with an error with message <code>'Error: socket hang up'</code> and code
2880<code>'ECONNRESET'</code></li>
2881<li><code>'close'</code></li>
2882</ul>
2883<p>If <code>req.destroy()</code> is called before the connection succeeds, the following
2884events will be emitted in the following order:</p>
2885<ul>
2886<li><code>'socket'</code></li>
2887<li>(<code>req.destroy()</code> called here)</li>
2888<li><code>'error'</code> with an error with message <code>'Error: socket hang up'</code> and code
2889<code>'ECONNRESET'</code></li>
2890<li><code>'close'</code></li>
2891</ul>
2892<p>If <code>req.destroy()</code> is called after the response is received, the following
2893events will be emitted in the following order:</p>
2894<ul>
2895<li><code>'socket'</code></li>
2896<li><code>'response'</code>
2897<ul>
2898<li><code>'data'</code> any number of times, on the <code>res</code> object</li>
2899</ul>
2900</li>
2901<li>(<code>req.destroy()</code> called here)</li>
2902<li><code>'aborted'</code> on the <code>res</code> object</li>
2903<li><code>'close'</code></li>
2904<li><code>'close'</code> on the <code>res</code> object</li>
2905</ul>
2906<p>If <code>req.abort()</code> is called before a socket is assigned, the following
2907events will be emitted in the following order:</p>
2908<ul>
2909<li>(<code>req.abort()</code> called here)</li>
2910<li><code>'abort'</code></li>
2911<li><code>'close'</code></li>
2912</ul>
2913<p>If <code>req.abort()</code> is called before the connection succeeds, the following
2914events will be emitted in the following order:</p>
2915<ul>
2916<li><code>'socket'</code></li>
2917<li>(<code>req.abort()</code> called here)</li>
2918<li><code>'abort'</code></li>
2919<li><code>'error'</code> with an error with message <code>'Error: socket hang up'</code> and code
2920<code>'ECONNRESET'</code></li>
2921<li><code>'close'</code></li>
2922</ul>
2923<p>If <code>req.abort()</code> is called after the response is received, the following
2924events will be emitted in the following order:</p>
2925<ul>
2926<li><code>'socket'</code></li>
2927<li><code>'response'</code>
2928<ul>
2929<li><code>'data'</code> any number of times, on the <code>res</code> object</li>
2930</ul>
2931</li>
2932<li>(<code>req.abort()</code> called here)</li>
2933<li><code>'abort'</code></li>
2934<li><code>'aborted'</code> on the <code>res</code> object</li>
2935<li><code>'close'</code></li>
2936<li><code>'close'</code> on the <code>res</code> object</li>
2937</ul>
2938<p>Setting the <code>timeout</code> option or using the <code>setTimeout()</code> function will
2939not abort the request or do anything besides add a <code>'timeout'</code> event.</p>
2940<p>Passing an <code>AbortSignal</code> and then calling <code>abort</code> on the corresponding
2941<code>AbortController</code> will behave the same way as calling <code>.destroy()</code> on the
2942request itself.</p>
2943</section><section><h3><code>http.validateHeaderName(name)</code><span><a class="mark" href="#http_http_validateheadername_name" id="http_http_validateheadername_name">#</a></span></h3>
2944<div class="api_metadata">
2945<span>Added in: v14.3.0</span>
2946</div>
2947<ul>
2948<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
2949</ul>
2950<p>Performs the low-level validations on the provided <code>name</code> that are done when
2951<code>res.setHeader(name, value)</code> is called.</p>
2952<p>Passing illegal value as <code>name</code> will result in a <a href="errors.html#errors_class_typeerror"><code>TypeError</code></a> being thrown,
2953identified by <code>code: 'ERR_INVALID_HTTP_TOKEN'</code>.</p>
2954<p>It is not necessary to use this method before passing headers to an HTTP request
2955or response. The HTTP module will automatically validate such headers.
2956Examples:</p>
2957<p>Example:</p>
2958<pre><code class="language-js"><span class="hljs-keyword">const</span> { validateHeaderName } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
2959
2960<span class="hljs-keyword">try</span> {
2961  <span class="hljs-title function_">validateHeaderName</span>(<span class="hljs-string">''</span>);
2962} <span class="hljs-keyword">catch</span> (err) {
2963  err <span class="hljs-keyword">instanceof</span> <span class="hljs-title class_">TypeError</span>; <span class="hljs-comment">// --> true</span>
2964  err.<span class="hljs-property">code</span>; <span class="hljs-comment">// --> 'ERR_INVALID_HTTP_TOKEN'</span>
2965  err.<span class="hljs-property">message</span>; <span class="hljs-comment">// --> 'Header name must be a valid HTTP token [""]'</span>
2966}</code></pre>
2967</section><section><h3><code>http.validateHeaderValue(name, value)</code><span><a class="mark" href="#http_http_validateheadervalue_name_value" id="http_http_validateheadervalue_name_value">#</a></span></h3>
2968<div class="api_metadata">
2969<span>Added in: v14.3.0</span>
2970</div>
2971<ul>
2972<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
2973<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type">&#x3C;any></a></li>
2974</ul>
2975<p>Performs the low-level validations on the provided <code>value</code> that are done when
2976<code>res.setHeader(name, value)</code> is called.</p>
2977<p>Passing illegal value as <code>value</code> will result in a <a href="errors.html#errors_class_typeerror"><code>TypeError</code></a> being thrown.</p>
2978<ul>
2979<li>Undefined value error is identified by <code>code: 'ERR_HTTP_INVALID_HEADER_VALUE'</code>.</li>
2980<li>Invalid value character error is identified by <code>code: 'ERR_INVALID_CHAR'</code>.</li>
2981</ul>
2982<p>It is not necessary to use this method before passing headers to an HTTP request
2983or response. The HTTP module will automatically validate such headers.</p>
2984<p>Examples:</p>
2985<pre><code class="language-js"><span class="hljs-keyword">const</span> { validateHeaderValue } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'http'</span>);
2986
2987<span class="hljs-keyword">try</span> {
2988  <span class="hljs-title function_">validateHeaderValue</span>(<span class="hljs-string">'x-my-header'</span>, <span class="hljs-literal">undefined</span>);
2989} <span class="hljs-keyword">catch</span> (err) {
2990  err <span class="hljs-keyword">instanceof</span> <span class="hljs-title class_">TypeError</span>; <span class="hljs-comment">// --> true</span>
2991  err.<span class="hljs-property">code</span> === <span class="hljs-string">'ERR_HTTP_INVALID_HEADER_VALUE'</span>; <span class="hljs-comment">// --> true</span>
2992  err.<span class="hljs-property">message</span>; <span class="hljs-comment">// --> 'Invalid value "undefined" for header "x-my-header"'</span>
2993}
2994
2995<span class="hljs-keyword">try</span> {
2996  <span class="hljs-title function_">validateHeaderValue</span>(<span class="hljs-string">'x-my-header'</span>, <span class="hljs-string">'oʊmɪɡə'</span>);
2997} <span class="hljs-keyword">catch</span> (err) {
2998  err <span class="hljs-keyword">instanceof</span> <span class="hljs-title class_">TypeError</span>; <span class="hljs-comment">// --> true</span>
2999  err.<span class="hljs-property">code</span> === <span class="hljs-string">'ERR_INVALID_CHAR'</span>; <span class="hljs-comment">// --> true</span>
3000  err.<span class="hljs-property">message</span>; <span class="hljs-comment">// --> 'Invalid character in header content ["x-my-header"]'</span>
3001}</code></pre></section>
3002        <!-- API END -->
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