1<!DOCTYPE html> 2<html lang="en"> 3<head> 4 <meta charset="utf-8"> 5 <meta name="viewport" content="width=device-width"> 6 <meta name="nodejs.org:node-version" content="v18.18.2"> 7 <title>Net | Node.js v18.18.2 Documentation</title> 8 <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lato:400,700,400italic&display=fallback"> 9 <link rel="stylesheet" href="assets/style.css"> 10 <link rel="stylesheet" href="assets/hljs.css"> 11 <link rel="canonical" href="https://nodejs.org/api/net.html"> 12 <script async defer src="assets/api.js" type="text/javascript"></script> 13 14</head> 15<body class="alt apidoc" id="api-section-net"> 16 <div id="content" class="clearfix"> 17 <div id="column2" class="interior"> 18 <div id="intro" class="interior"> 19 <a href="/" title="Go back to the home page"> 20 Node.js 21 </a> 22 </div> 23 <ul> 24<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li> 25<li><a href="synopsis.html" 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class="picker-header"> 117 <a href="#"> 118 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 119 Table of contents 120 </a> 121 122 <div class="picker"><div class="toc"><ul> 123<li><span class="stability_2"><a href="#net">Net</a></span> 124<ul> 125<li><a href="#ipc-support">IPC support</a> 126<ul> 127<li><a href="#identifying-paths-for-ipc-connections">Identifying paths for IPC connections</a></li> 128</ul> 129</li> 130<li><a href="#class-netblocklist">Class: <code>net.BlockList</code></a> 131<ul> 132<li><a href="#blocklistaddaddressaddress-type"><code>blockList.addAddress(address[, type])</code></a></li> 133<li><a href="#blocklistaddrangestart-end-type"><code>blockList.addRange(start, end[, type])</code></a></li> 134<li><a href="#blocklistaddsubnetnet-prefix-type"><code>blockList.addSubnet(net, prefix[, type])</code></a></li> 135<li><a href="#blocklistcheckaddress-type"><code>blockList.check(address[, type])</code></a></li> 136<li><a href="#blocklistrules"><code>blockList.rules</code></a></li> 137</ul> 138</li> 139<li><a href="#class-netsocketaddress">Class: <code>net.SocketAddress</code></a> 140<ul> 141<li><a href="#new-netsocketaddressoptions"><code>new net.SocketAddress([options])</code></a></li> 142<li><a href="#socketaddressaddress"><code>socketaddress.address</code></a></li> 143<li><a href="#socketaddressfamily"><code>socketaddress.family</code></a></li> 144<li><a href="#socketaddressflowlabel"><code>socketaddress.flowlabel</code></a></li> 145<li><a href="#socketaddressport"><code>socketaddress.port</code></a></li> 146</ul> 147</li> 148<li><a href="#class-netserver">Class: <code>net.Server</code></a> 149<ul> 150<li><a href="#new-netserveroptions-connectionlistener"><code>new net.Server([options][, connectionListener])</code></a></li> 151<li><a href="#event-close">Event: <code>'close'</code></a></li> 152<li><a href="#event-connection">Event: <code>'connection'</code></a></li> 153<li><a href="#event-error">Event: <code>'error'</code></a></li> 154<li><a href="#event-listening">Event: <code>'listening'</code></a></li> 155<li><a href="#event-drop">Event: <code>'drop'</code></a></li> 156<li><a href="#serveraddress"><code>server.address()</code></a></li> 157<li><a href="#serverclosecallback"><code>server.close([callback])</code></a></li> 158<li><span class="stability_1"><a href="#serversymbolasyncdispose"><code>server[Symbol.asyncDispose]()</code></a></span></li> 159<li><a href="#servergetconnectionscallback"><code>server.getConnections(callback)</code></a></li> 160<li><a href="#serverlisten"><code>server.listen()</code></a> 161<ul> 162<li><a href="#serverlistenhandle-backlog-callback"><code>server.listen(handle[, backlog][, callback])</code></a></li> 163<li><a href="#serverlistenoptions-callback"><code>server.listen(options[, callback])</code></a></li> 164<li><a href="#serverlistenpath-backlog-callback"><code>server.listen(path[, backlog][, callback])</code></a></li> 165<li><a href="#serverlistenport-host-backlog-callback"><code>server.listen([port[, host[, backlog]]][, callback])</code></a></li> 166</ul> 167</li> 168<li><a href="#serverlistening"><code>server.listening</code></a></li> 169<li><a href="#servermaxconnections"><code>server.maxConnections</code></a></li> 170<li><a href="#serverref"><code>server.ref()</code></a></li> 171<li><a href="#serverunref"><code>server.unref()</code></a></li> 172</ul> 173</li> 174<li><a href="#class-netsocket">Class: <code>net.Socket</code></a> 175<ul> 176<li><a href="#new-netsocketoptions"><code>new net.Socket([options])</code></a></li> 177<li><a href="#event-close_1">Event: <code>'close'</code></a></li> 178<li><a href="#event-connect">Event: <code>'connect'</code></a></li> 179<li><a href="#event-data">Event: <code>'data'</code></a></li> 180<li><a href="#event-drain">Event: <code>'drain'</code></a></li> 181<li><a href="#event-end">Event: <code>'end'</code></a></li> 182<li><a href="#event-error_1">Event: <code>'error'</code></a></li> 183<li><a href="#event-lookup">Event: <code>'lookup'</code></a></li> 184<li><a href="#event-ready">Event: <code>'ready'</code></a></li> 185<li><a href="#event-timeout">Event: <code>'timeout'</code></a></li> 186<li><a href="#socketaddress"><code>socket.address()</code></a></li> 187<li><a href="#socketautoselectfamilyattemptedaddresses"><code>socket.autoSelectFamilyAttemptedAddresses</code></a></li> 188<li><span class="stability_0"><a href="#socketbuffersize"><code>socket.bufferSize</code></a></span></li> 189<li><a href="#socketbytesread"><code>socket.bytesRead</code></a></li> 190<li><a href="#socketbyteswritten"><code>socket.bytesWritten</code></a></li> 191<li><a href="#socketconnect"><code>socket.connect()</code></a> 192<ul> 193<li><a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a></li> 194<li><a href="#socketconnectpath-connectlistener"><code>socket.connect(path[, connectListener])</code></a></li> 195<li><a href="#socketconnectport-host-connectlistener"><code>socket.connect(port[, host][, connectListener])</code></a></li> 196</ul> 197</li> 198<li><a href="#socketconnecting"><code>socket.connecting</code></a></li> 199<li><a href="#socketdestroyerror"><code>socket.destroy([error])</code></a></li> 200<li><a href="#socketdestroyed"><code>socket.destroyed</code></a></li> 201<li><a href="#socketdestroysoon"><code>socket.destroySoon()</code></a></li> 202<li><a href="#socketenddata-encoding-callback"><code>socket.end([data[, encoding]][, callback])</code></a></li> 203<li><a href="#socketlocaladdress"><code>socket.localAddress</code></a></li> 204<li><a href="#socketlocalport"><code>socket.localPort</code></a></li> 205<li><a href="#socketlocalfamily"><code>socket.localFamily</code></a></li> 206<li><a href="#socketpause"><code>socket.pause()</code></a></li> 207<li><a href="#socketpending"><code>socket.pending</code></a></li> 208<li><a href="#socketref"><code>socket.ref()</code></a></li> 209<li><a href="#socketremoteaddress"><code>socket.remoteAddress</code></a></li> 210<li><a href="#socketremotefamily"><code>socket.remoteFamily</code></a></li> 211<li><a href="#socketremoteport"><code>socket.remotePort</code></a></li> 212<li><a href="#socketresetanddestroy"><code>socket.resetAndDestroy()</code></a></li> 213<li><a href="#socketresume"><code>socket.resume()</code></a></li> 214<li><a href="#socketsetencodingencoding"><code>socket.setEncoding([encoding])</code></a></li> 215<li><a href="#socketsetkeepaliveenable-initialdelay"><code>socket.setKeepAlive([enable][, initialDelay])</code></a></li> 216<li><a href="#socketsetnodelaynodelay"><code>socket.setNoDelay([noDelay])</code></a></li> 217<li><a href="#socketsettimeouttimeout-callback"><code>socket.setTimeout(timeout[, callback])</code></a></li> 218<li><a href="#sockettimeout"><code>socket.timeout</code></a></li> 219<li><a href="#socketunref"><code>socket.unref()</code></a></li> 220<li><a href="#socketwritedata-encoding-callback"><code>socket.write(data[, encoding][, callback])</code></a></li> 221<li><a href="#socketreadystate"><code>socket.readyState</code></a></li> 222</ul> 223</li> 224<li><a href="#netconnect"><code>net.connect()</code></a> 225<ul> 226<li><a href="#netconnectoptions-connectlistener"><code>net.connect(options[, connectListener])</code></a></li> 227<li><a href="#netconnectpath-connectlistener"><code>net.connect(path[, connectListener])</code></a></li> 228<li><a href="#netconnectport-host-connectlistener"><code>net.connect(port[, host][, connectListener])</code></a></li> 229</ul> 230</li> 231<li><a href="#netcreateconnection"><code>net.createConnection()</code></a> 232<ul> 233<li><a href="#netcreateconnectionoptions-connectlistener"><code>net.createConnection(options[, connectListener])</code></a></li> 234<li><a href="#netcreateconnectionpath-connectlistener"><code>net.createConnection(path[, connectListener])</code></a></li> 235<li><a href="#netcreateconnectionport-host-connectlistener"><code>net.createConnection(port[, host][, connectListener])</code></a></li> 236</ul> 237</li> 238<li><a href="#netcreateserveroptions-connectionlistener"><code>net.createServer([options][, connectionListener])</code></a></li> 239<li><a href="#netgetdefaultautoselectfamily"><code>net.getDefaultAutoSelectFamily()</code></a></li> 240<li><a href="#netsetdefaultautoselectfamilyvalue"><code>net.setDefaultAutoSelectFamily(value)</code></a></li> 241<li><a href="#netgetdefaultautoselectfamilyattempttimeout"><code>net.getDefaultAutoSelectFamilyAttemptTimeout()</code></a></li> 242<li><a href="#netsetdefaultautoselectfamilyattempttimeoutvalue"><code>net.setDefaultAutoSelectFamilyAttemptTimeout(value)</code></a></li> 243<li><a href="#netisipinput"><code>net.isIP(input)</code></a></li> 244<li><a href="#netisipv4input"><code>net.isIPv4(input)</code></a></li> 245<li><a href="#netisipv6input"><code>net.isIPv6(input)</code></a></li> 246</ul> 247</li> 248</ul></div></div> 249 </li> 250 251 252 <li class="picker-header"> 253 <a href="#"> 254 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 255 Index 256 </a> 257 258 <div class="picker"><ul> 259<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li> 260<li><a href="synopsis.html" class="nav-synopsis">Usage and example</a></li> 261 262 <li> 263 <a href="index.html">Index</a> 264 </li> 265 </ul> 266 267<hr class="line"> 268<ul> 269<li><a href="assert.html" class="nav-assert">Assertion testing</a></li> 270<li><a href="async_context.html" class="nav-async_context">Asynchronous context tracking</a></li> 271<li><a href="async_hooks.html" class="nav-async_hooks">Async hooks</a></li> 272<li><a href="buffer.html" class="nav-buffer">Buffer</a></li> 273<li><a href="addons.html" class="nav-addons">C++ addons</a></li> 274<li><a href="n-api.html" class="nav-n-api">C/C++ addons with Node-API</a></li> 275<li><a href="embedding.html" 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class="nav-tls">TLS/SSL</a></li> 317<li><a href="tracing.html" class="nav-tracing">Trace events</a></li> 318<li><a href="tty.html" class="nav-tty">TTY</a></li> 319<li><a href="dgram.html" class="nav-dgram">UDP/datagram</a></li> 320<li><a href="url.html" class="nav-url">URL</a></li> 321<li><a href="util.html" class="nav-util">Utilities</a></li> 322<li><a href="v8.html" class="nav-v8">V8</a></li> 323<li><a href="vm.html" class="nav-vm">VM</a></li> 324<li><a href="wasi.html" class="nav-wasi">WASI</a></li> 325<li><a href="webcrypto.html" class="nav-webcrypto">Web Crypto API</a></li> 326<li><a href="webstreams.html" class="nav-webstreams">Web Streams API</a></li> 327<li><a href="worker_threads.html" class="nav-worker_threads">Worker threads</a></li> 328<li><a href="zlib.html" class="nav-zlib">Zlib</a></li> 329</ul> 330<hr class="line"> 331<ul> 332<li><a href="https://github.com/nodejs/node" class="nav-https-github-com-nodejs-node">Code repository and issue tracker</a></li> 333</ul></div> 334 </li> 335 336 337 <li class="picker-header"> 338 <a href="#"> 339 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 340 Other versions 341 </a> 342 <div class="picker"><ol id="alt-docs"><li><a href="https://nodejs.org/docs/latest-v20.x/api/net.html">20.x</a></li> 343<li><a href="https://nodejs.org/docs/latest-v19.x/api/net.html">19.x</a></li> 344<li><a href="https://nodejs.org/docs/latest-v18.x/api/net.html">18.x <b>LTS</b></a></li> 345<li><a href="https://nodejs.org/docs/latest-v17.x/api/net.html">17.x</a></li> 346<li><a href="https://nodejs.org/docs/latest-v16.x/api/net.html">16.x</a></li> 347<li><a href="https://nodejs.org/docs/latest-v15.x/api/net.html">15.x</a></li> 348<li><a href="https://nodejs.org/docs/latest-v14.x/api/net.html">14.x</a></li> 349<li><a href="https://nodejs.org/docs/latest-v13.x/api/net.html">13.x</a></li> 350<li><a href="https://nodejs.org/docs/latest-v12.x/api/net.html">12.x</a></li> 351<li><a href="https://nodejs.org/docs/latest-v11.x/api/net.html">11.x</a></li> 352<li><a href="https://nodejs.org/docs/latest-v10.x/api/net.html">10.x</a></li> 353<li><a href="https://nodejs.org/docs/latest-v9.x/api/net.html">9.x</a></li> 354<li><a href="https://nodejs.org/docs/latest-v8.x/api/net.html">8.x</a></li> 355<li><a href="https://nodejs.org/docs/latest-v7.x/api/net.html">7.x</a></li> 356<li><a href="https://nodejs.org/docs/latest-v6.x/api/net.html">6.x</a></li> 357<li><a href="https://nodejs.org/docs/latest-v5.x/api/net.html">5.x</a></li> 358<li><a href="https://nodejs.org/docs/latest-v4.x/api/net.html">4.x</a></li> 359<li><a href="https://nodejs.org/docs/latest-v0.12.x/api/net.html">0.12.x</a></li> 360<li><a href="https://nodejs.org/docs/latest-v0.10.x/api/net.html">0.10.x</a></li></ol></div> 361 </li> 362 363 <li class="picker-header"> 364 <a href="#"> 365 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 366 Options 367 </a> 368 369 <div class="picker"> 370 <ul> 371 <li> 372 <a href="all.html">View on single page</a> 373 </li> 374 <li> 375 <a href="net.json">View as JSON</a> 376 </li> 377 <li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/main/doc/api/net.md">Edit on GitHub</a></li> 378 </ul> 379 </div> 380 </li> 381 </ul> 382 </div> 383 <hr> 384 </header> 385 386 <details id="toc" open><summary>Table of contents</summary><ul> 387<li><span class="stability_2"><a href="#net">Net</a></span> 388<ul> 389<li><a href="#ipc-support">IPC support</a> 390<ul> 391<li><a href="#identifying-paths-for-ipc-connections">Identifying paths for IPC connections</a></li> 392</ul> 393</li> 394<li><a href="#class-netblocklist">Class: <code>net.BlockList</code></a> 395<ul> 396<li><a href="#blocklistaddaddressaddress-type"><code>blockList.addAddress(address[, type])</code></a></li> 397<li><a href="#blocklistaddrangestart-end-type"><code>blockList.addRange(start, end[, type])</code></a></li> 398<li><a href="#blocklistaddsubnetnet-prefix-type"><code>blockList.addSubnet(net, prefix[, type])</code></a></li> 399<li><a href="#blocklistcheckaddress-type"><code>blockList.check(address[, type])</code></a></li> 400<li><a href="#blocklistrules"><code>blockList.rules</code></a></li> 401</ul> 402</li> 403<li><a href="#class-netsocketaddress">Class: <code>net.SocketAddress</code></a> 404<ul> 405<li><a href="#new-netsocketaddressoptions"><code>new net.SocketAddress([options])</code></a></li> 406<li><a href="#socketaddressaddress"><code>socketaddress.address</code></a></li> 407<li><a href="#socketaddressfamily"><code>socketaddress.family</code></a></li> 408<li><a href="#socketaddressflowlabel"><code>socketaddress.flowlabel</code></a></li> 409<li><a href="#socketaddressport"><code>socketaddress.port</code></a></li> 410</ul> 411</li> 412<li><a href="#class-netserver">Class: <code>net.Server</code></a> 413<ul> 414<li><a href="#new-netserveroptions-connectionlistener"><code>new net.Server([options][, connectionListener])</code></a></li> 415<li><a href="#event-close">Event: <code>'close'</code></a></li> 416<li><a href="#event-connection">Event: <code>'connection'</code></a></li> 417<li><a href="#event-error">Event: <code>'error'</code></a></li> 418<li><a href="#event-listening">Event: <code>'listening'</code></a></li> 419<li><a href="#event-drop">Event: <code>'drop'</code></a></li> 420<li><a href="#serveraddress"><code>server.address()</code></a></li> 421<li><a href="#serverclosecallback"><code>server.close([callback])</code></a></li> 422<li><span class="stability_1"><a href="#serversymbolasyncdispose"><code>server[Symbol.asyncDispose]()</code></a></span></li> 423<li><a href="#servergetconnectionscallback"><code>server.getConnections(callback)</code></a></li> 424<li><a href="#serverlisten"><code>server.listen()</code></a> 425<ul> 426<li><a href="#serverlistenhandle-backlog-callback"><code>server.listen(handle[, backlog][, callback])</code></a></li> 427<li><a href="#serverlistenoptions-callback"><code>server.listen(options[, callback])</code></a></li> 428<li><a href="#serverlistenpath-backlog-callback"><code>server.listen(path[, backlog][, callback])</code></a></li> 429<li><a href="#serverlistenport-host-backlog-callback"><code>server.listen([port[, host[, backlog]]][, callback])</code></a></li> 430</ul> 431</li> 432<li><a href="#serverlistening"><code>server.listening</code></a></li> 433<li><a href="#servermaxconnections"><code>server.maxConnections</code></a></li> 434<li><a href="#serverref"><code>server.ref()</code></a></li> 435<li><a href="#serverunref"><code>server.unref()</code></a></li> 436</ul> 437</li> 438<li><a href="#class-netsocket">Class: <code>net.Socket</code></a> 439<ul> 440<li><a href="#new-netsocketoptions"><code>new net.Socket([options])</code></a></li> 441<li><a href="#event-close_1">Event: <code>'close'</code></a></li> 442<li><a href="#event-connect">Event: <code>'connect'</code></a></li> 443<li><a href="#event-data">Event: <code>'data'</code></a></li> 444<li><a href="#event-drain">Event: <code>'drain'</code></a></li> 445<li><a href="#event-end">Event: <code>'end'</code></a></li> 446<li><a href="#event-error_1">Event: <code>'error'</code></a></li> 447<li><a href="#event-lookup">Event: <code>'lookup'</code></a></li> 448<li><a href="#event-ready">Event: <code>'ready'</code></a></li> 449<li><a href="#event-timeout">Event: <code>'timeout'</code></a></li> 450<li><a href="#socketaddress"><code>socket.address()</code></a></li> 451<li><a href="#socketautoselectfamilyattemptedaddresses"><code>socket.autoSelectFamilyAttemptedAddresses</code></a></li> 452<li><span class="stability_0"><a href="#socketbuffersize"><code>socket.bufferSize</code></a></span></li> 453<li><a href="#socketbytesread"><code>socket.bytesRead</code></a></li> 454<li><a href="#socketbyteswritten"><code>socket.bytesWritten</code></a></li> 455<li><a href="#socketconnect"><code>socket.connect()</code></a> 456<ul> 457<li><a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a></li> 458<li><a href="#socketconnectpath-connectlistener"><code>socket.connect(path[, connectListener])</code></a></li> 459<li><a href="#socketconnectport-host-connectlistener"><code>socket.connect(port[, host][, connectListener])</code></a></li> 460</ul> 461</li> 462<li><a href="#socketconnecting"><code>socket.connecting</code></a></li> 463<li><a href="#socketdestroyerror"><code>socket.destroy([error])</code></a></li> 464<li><a href="#socketdestroyed"><code>socket.destroyed</code></a></li> 465<li><a href="#socketdestroysoon"><code>socket.destroySoon()</code></a></li> 466<li><a href="#socketenddata-encoding-callback"><code>socket.end([data[, encoding]][, callback])</code></a></li> 467<li><a href="#socketlocaladdress"><code>socket.localAddress</code></a></li> 468<li><a href="#socketlocalport"><code>socket.localPort</code></a></li> 469<li><a href="#socketlocalfamily"><code>socket.localFamily</code></a></li> 470<li><a href="#socketpause"><code>socket.pause()</code></a></li> 471<li><a href="#socketpending"><code>socket.pending</code></a></li> 472<li><a href="#socketref"><code>socket.ref()</code></a></li> 473<li><a href="#socketremoteaddress"><code>socket.remoteAddress</code></a></li> 474<li><a href="#socketremotefamily"><code>socket.remoteFamily</code></a></li> 475<li><a href="#socketremoteport"><code>socket.remotePort</code></a></li> 476<li><a href="#socketresetanddestroy"><code>socket.resetAndDestroy()</code></a></li> 477<li><a href="#socketresume"><code>socket.resume()</code></a></li> 478<li><a href="#socketsetencodingencoding"><code>socket.setEncoding([encoding])</code></a></li> 479<li><a href="#socketsetkeepaliveenable-initialdelay"><code>socket.setKeepAlive([enable][, initialDelay])</code></a></li> 480<li><a href="#socketsetnodelaynodelay"><code>socket.setNoDelay([noDelay])</code></a></li> 481<li><a href="#socketsettimeouttimeout-callback"><code>socket.setTimeout(timeout[, callback])</code></a></li> 482<li><a href="#sockettimeout"><code>socket.timeout</code></a></li> 483<li><a href="#socketunref"><code>socket.unref()</code></a></li> 484<li><a href="#socketwritedata-encoding-callback"><code>socket.write(data[, encoding][, callback])</code></a></li> 485<li><a href="#socketreadystate"><code>socket.readyState</code></a></li> 486</ul> 487</li> 488<li><a href="#netconnect"><code>net.connect()</code></a> 489<ul> 490<li><a href="#netconnectoptions-connectlistener"><code>net.connect(options[, connectListener])</code></a></li> 491<li><a href="#netconnectpath-connectlistener"><code>net.connect(path[, connectListener])</code></a></li> 492<li><a href="#netconnectport-host-connectlistener"><code>net.connect(port[, host][, connectListener])</code></a></li> 493</ul> 494</li> 495<li><a href="#netcreateconnection"><code>net.createConnection()</code></a> 496<ul> 497<li><a href="#netcreateconnectionoptions-connectlistener"><code>net.createConnection(options[, connectListener])</code></a></li> 498<li><a href="#netcreateconnectionpath-connectlistener"><code>net.createConnection(path[, connectListener])</code></a></li> 499<li><a href="#netcreateconnectionport-host-connectlistener"><code>net.createConnection(port[, host][, connectListener])</code></a></li> 500</ul> 501</li> 502<li><a href="#netcreateserveroptions-connectionlistener"><code>net.createServer([options][, connectionListener])</code></a></li> 503<li><a href="#netgetdefaultautoselectfamily"><code>net.getDefaultAutoSelectFamily()</code></a></li> 504<li><a href="#netsetdefaultautoselectfamilyvalue"><code>net.setDefaultAutoSelectFamily(value)</code></a></li> 505<li><a href="#netgetdefaultautoselectfamilyattempttimeout"><code>net.getDefaultAutoSelectFamilyAttemptTimeout()</code></a></li> 506<li><a href="#netsetdefaultautoselectfamilyattempttimeoutvalue"><code>net.setDefaultAutoSelectFamilyAttemptTimeout(value)</code></a></li> 507<li><a href="#netisipinput"><code>net.isIP(input)</code></a></li> 508<li><a href="#netisipv4input"><code>net.isIPv4(input)</code></a></li> 509<li><a href="#netisipv6input"><code>net.isIPv6(input)</code></a></li> 510</ul> 511</li> 512</ul></details> 513 514 <div id="apicontent"> 515 <h2>Net<span><a class="mark" href="#net" id="net">#</a></span><a aria-hidden="true" class="legacy" id="net_net"></a></h2> 516 517<!--lint disable maximum-line-length--> 518<p></p><div class="api_stability api_stability_2"><a href="documentation.html#stability-index">Stability: 2</a> - Stable</div><p></p> 519<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v18.18.2/lib/net.js">lib/net.js</a></p> 520<p>The <code>node:net</code> module provides an asynchronous network API for creating stream-based 521TCP or <a href="#ipc-support">IPC</a> servers (<a href="#netcreateserveroptions-connectionlistener"><code>net.createServer()</code></a>) and clients 522(<a href="#netcreateconnection"><code>net.createConnection()</code></a>).</p> 523<p>It can be accessed using:</p> 524<pre><code class="language-js"><span class="hljs-keyword">const</span> net = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:net'</span>);</code> <button class="copy-button">copy</button></pre> 525<section><h3>IPC support<span><a class="mark" href="#ipc-support" id="ipc-support">#</a></span><a aria-hidden="true" class="legacy" id="net_ipc_support"></a></h3> 526<p>The <code>node:net</code> module supports IPC with named pipes on Windows, and Unix domain 527sockets on other operating systems.</p> 528<h4>Identifying paths for IPC connections<span><a class="mark" href="#identifying-paths-for-ipc-connections" id="identifying-paths-for-ipc-connections">#</a></span><a aria-hidden="true" class="legacy" id="net_identifying_paths_for_ipc_connections"></a></h4> 529<p><a href="#netconnect"><code>net.connect()</code></a>, <a href="#netcreateconnection"><code>net.createConnection()</code></a>, <a href="#serverlisten"><code>server.listen()</code></a>, and 530<a href="#socketconnect"><code>socket.connect()</code></a> take a <code>path</code> parameter to identify IPC endpoints.</p> 531<p>On Unix, the local domain is also known as the Unix domain. The path is a 532file system pathname. It gets truncated to an OS-dependent length of 533<code>sizeof(sockaddr_un.sun_path) - 1</code>. Typical values are 107 bytes on Linux and 534103 bytes on macOS. If a Node.js API abstraction creates the Unix domain socket, 535it will unlink the Unix domain socket as well. For example, 536<a href="#netcreateserveroptions-connectionlistener"><code>net.createServer()</code></a> may create a Unix domain socket and 537<a href="#serverclosecallback"><code>server.close()</code></a> will unlink it. But if a user creates the Unix domain 538socket outside of these abstractions, the user will need to remove it. The same 539applies when a Node.js API creates a Unix domain socket but the program then 540crashes. In short, a Unix domain socket will be visible in the file system and 541will persist until unlinked.</p> 542<p>On Windows, the local domain is implemented using a named pipe. The path <em>must</em> 543refer to an entry in <code>\\?\pipe\</code> or <code>\\.\pipe\</code>. Any characters are permitted, 544but the latter may do some processing of pipe names, such as resolving <code>..</code> 545sequences. Despite how it might look, the pipe namespace is flat. Pipes will 546<em>not persist</em>. They are removed when the last reference to them is closed. 547Unlike Unix domain sockets, Windows will close and remove the pipe when the 548owning process exits.</p> 549<p>JavaScript string escaping requires paths to be specified with extra backslash 550escaping such as:</p> 551<pre><code class="language-js">net.<span class="hljs-title function_">createServer</span>().<span class="hljs-title function_">listen</span>( 552 path.<span class="hljs-title function_">join</span>(<span class="hljs-string">'\\\\?\\pipe'</span>, process.<span class="hljs-title function_">cwd</span>(), <span class="hljs-string">'myctl'</span>));</code> <button class="copy-button">copy</button></pre> 553</section><section><h3>Class: <code>net.BlockList</code><span><a class="mark" href="#class-netblocklist" id="class-netblocklist">#</a></span><a aria-hidden="true" class="legacy" id="net_class_net_blocklist"></a></h3> 554<div class="api_metadata"> 555<span>Added in: v15.0.0, v14.18.0</span> 556</div> 557<p>The <code>BlockList</code> object can be used with some network APIs to specify rules for 558disabling inbound or outbound access to specific IP addresses, IP ranges, or 559IP subnets.</p> 560<h4><code>blockList.addAddress(address[, type])</code><span><a class="mark" href="#blocklistaddaddressaddress-type" id="blocklistaddaddressaddress-type">#</a></span><a aria-hidden="true" class="legacy" id="net_blocklist_addaddress_address_type"></a></h4> 561<div class="api_metadata"> 562<span>Added in: v15.0.0, v14.18.0</span> 563</div> 564<ul> 565<li><code>address</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="net.html#class-netsocketaddress" class="type"><net.SocketAddress></a> An IPv4 or IPv6 address.</li> 566<li><code>type</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Either <code>'ipv4'</code> or <code>'ipv6'</code>. <strong>Default:</strong> <code>'ipv4'</code>.</li> 567</ul> 568<p>Adds a rule to block the given IP address.</p> 569<h4><code>blockList.addRange(start, end[, type])</code><span><a class="mark" href="#blocklistaddrangestart-end-type" id="blocklistaddrangestart-end-type">#</a></span><a aria-hidden="true" class="legacy" id="net_blocklist_addrange_start_end_type"></a></h4> 570<div class="api_metadata"> 571<span>Added in: v15.0.0, v14.18.0</span> 572</div> 573<ul> 574<li><code>start</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="net.html#class-netsocketaddress" class="type"><net.SocketAddress></a> The starting IPv4 or IPv6 address in the 575range.</li> 576<li><code>end</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="net.html#class-netsocketaddress" class="type"><net.SocketAddress></a> The ending IPv4 or IPv6 address in the range.</li> 577<li><code>type</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Either <code>'ipv4'</code> or <code>'ipv6'</code>. <strong>Default:</strong> <code>'ipv4'</code>.</li> 578</ul> 579<p>Adds a rule to block a range of IP addresses from <code>start</code> (inclusive) to 580<code>end</code> (inclusive).</p> 581<h4><code>blockList.addSubnet(net, prefix[, type])</code><span><a class="mark" href="#blocklistaddsubnetnet-prefix-type" id="blocklistaddsubnetnet-prefix-type">#</a></span><a aria-hidden="true" class="legacy" id="net_blocklist_addsubnet_net_prefix_type"></a></h4> 582<div class="api_metadata"> 583<span>Added in: v15.0.0, v14.18.0</span> 584</div> 585<ul> 586<li><code>net</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="net.html#class-netsocketaddress" class="type"><net.SocketAddress></a> The network IPv4 or IPv6 address.</li> 587<li><code>prefix</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> The number of CIDR prefix bits. For IPv4, this 588must be a value between <code>0</code> and <code>32</code>. For IPv6, this must be between 589<code>0</code> and <code>128</code>.</li> 590<li><code>type</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Either <code>'ipv4'</code> or <code>'ipv6'</code>. <strong>Default:</strong> <code>'ipv4'</code>.</li> 591</ul> 592<p>Adds a rule to block a range of IP addresses specified as a subnet mask.</p> 593<h4><code>blockList.check(address[, type])</code><span><a class="mark" href="#blocklistcheckaddress-type" id="blocklistcheckaddress-type">#</a></span><a aria-hidden="true" class="legacy" id="net_blocklist_check_address_type"></a></h4> 594<div class="api_metadata"> 595<span>Added in: v15.0.0, v14.18.0</span> 596</div> 597<ul> 598<li><code>address</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="net.html#class-netsocketaddress" class="type"><net.SocketAddress></a> The IP address to check</li> 599<li><code>type</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Either <code>'ipv4'</code> or <code>'ipv6'</code>. <strong>Default:</strong> <code>'ipv4'</code>.</li> 600<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 601</ul> 602<p>Returns <code>true</code> if the given IP address matches any of the rules added to the 603<code>BlockList</code>.</p> 604<pre><code class="language-js"><span class="hljs-keyword">const</span> blockList = <span class="hljs-keyword">new</span> net.<span class="hljs-title class_">BlockList</span>(); 605blockList.<span class="hljs-title function_">addAddress</span>(<span class="hljs-string">'123.123.123.123'</span>); 606blockList.<span class="hljs-title function_">addRange</span>(<span class="hljs-string">'10.0.0.1'</span>, <span class="hljs-string">'10.0.0.10'</span>); 607blockList.<span class="hljs-title function_">addSubnet</span>(<span class="hljs-string">'8592:757c:efae:4e45::'</span>, <span class="hljs-number">64</span>, <span class="hljs-string">'ipv6'</span>); 608 609<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(blockList.<span class="hljs-title function_">check</span>(<span class="hljs-string">'123.123.123.123'</span>)); <span class="hljs-comment">// Prints: true</span> 610<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(blockList.<span class="hljs-title function_">check</span>(<span class="hljs-string">'10.0.0.3'</span>)); <span class="hljs-comment">// Prints: true</span> 611<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(blockList.<span class="hljs-title function_">check</span>(<span class="hljs-string">'222.111.111.222'</span>)); <span class="hljs-comment">// Prints: false</span> 612 613<span class="hljs-comment">// IPv6 notation for IPv4 addresses works:</span> 614<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(blockList.<span class="hljs-title function_">check</span>(<span class="hljs-string">'::ffff:7b7b:7b7b'</span>, <span class="hljs-string">'ipv6'</span>)); <span class="hljs-comment">// Prints: true</span> 615<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(blockList.<span class="hljs-title function_">check</span>(<span class="hljs-string">'::ffff:123.123.123.123'</span>, <span class="hljs-string">'ipv6'</span>)); <span class="hljs-comment">// Prints: true</span></code> <button class="copy-button">copy</button></pre> 616<h4><code>blockList.rules</code><span><a class="mark" href="#blocklistrules" id="blocklistrules">#</a></span><a aria-hidden="true" class="legacy" id="net_blocklist_rules"></a></h4> 617<div class="api_metadata"> 618<span>Added in: v15.0.0, v14.18.0</span> 619</div> 620<ul> 621<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string[]></a></li> 622</ul> 623<p>The list of rules added to the blocklist.</p> 624</section><section><h3>Class: <code>net.SocketAddress</code><span><a class="mark" href="#class-netsocketaddress" id="class-netsocketaddress">#</a></span><a aria-hidden="true" class="legacy" id="net_class_net_socketaddress"></a></h3> 625<div class="api_metadata"> 626<span>Added in: v15.14.0, v14.18.0</span> 627</div> 628<h4><code>new net.SocketAddress([options])</code><span><a class="mark" href="#new-netsocketaddressoptions" id="new-netsocketaddressoptions">#</a></span><a aria-hidden="true" class="legacy" id="net_new_net_socketaddress_options"></a></h4> 629<div class="api_metadata"> 630<span>Added in: v15.14.0, v14.18.0</span> 631</div> 632<ul> 633<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 634<ul> 635<li><code>address</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The network address as either an IPv4 or IPv6 string. 636<strong>Default</strong>: <code>'127.0.0.1'</code> if <code>family</code> is <code>'ipv4'</code>; <code>'::'</code> if <code>family</code> is 637<code>'ipv6'</code>.</li> 638<li><code>family</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> One of either <code>'ipv4'</code> or <code>'ipv6'</code>. 639<strong>Default</strong>: <code>'ipv4'</code>.</li> 640<li><code>flowlabel</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> An IPv6 flow-label used only if <code>family</code> is <code>'ipv6'</code>.</li> 641<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> An IP port.</li> 642</ul> 643</li> 644</ul> 645<h4><code>socketaddress.address</code><span><a class="mark" href="#socketaddressaddress" id="socketaddressaddress">#</a></span><a aria-hidden="true" class="legacy" id="net_socketaddress_address"></a></h4> 646<div class="api_metadata"> 647<span>Added in: v15.14.0, v14.18.0</span> 648</div> 649<ul> 650<li>Type <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 651</ul> 652<h4><code>socketaddress.family</code><span><a class="mark" href="#socketaddressfamily" id="socketaddressfamily">#</a></span><a aria-hidden="true" class="legacy" id="net_socketaddress_family"></a></h4> 653<div class="api_metadata"> 654<span>Added in: v15.14.0, v14.18.0</span> 655</div> 656<ul> 657<li>Type <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Either <code>'ipv4'</code> or <code>'ipv6'</code>.</li> 658</ul> 659<h4><code>socketaddress.flowlabel</code><span><a class="mark" href="#socketaddressflowlabel" id="socketaddressflowlabel">#</a></span><a aria-hidden="true" class="legacy" id="net_socketaddress_flowlabel"></a></h4> 660<div class="api_metadata"> 661<span>Added in: v15.14.0, v14.18.0</span> 662</div> 663<ul> 664<li>Type <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 665</ul> 666<h4><code>socketaddress.port</code><span><a class="mark" href="#socketaddressport" id="socketaddressport">#</a></span><a aria-hidden="true" class="legacy" id="net_socketaddress_port"></a></h4> 667<div class="api_metadata"> 668<span>Added in: v15.14.0, v14.18.0</span> 669</div> 670<ul> 671<li>Type <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 672</ul> 673</section><section><h3>Class: <code>net.Server</code><span><a class="mark" href="#class-netserver" id="class-netserver">#</a></span><a aria-hidden="true" class="legacy" id="net_class_net_server"></a></h3> 674<div class="api_metadata"> 675<span>Added in: v0.1.90</span> 676</div> 677<ul> 678<li>Extends: <a href="events.html#class-eventemitter" class="type"><EventEmitter></a></li> 679</ul> 680<p>This class is used to create a TCP or <a href="#ipc-support">IPC</a> server.</p> 681<h4><code>new net.Server([options][, connectionListener])</code><span><a class="mark" href="#new-netserveroptions-connectionlistener" id="new-netserveroptions-connectionlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_new_net_server_options_connectionlistener"></a></h4> 682<ul> 683<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> See 684<a href="#netcreateserveroptions-connectionlistener"><code>net.createServer([options][, connectionListener])</code></a>.</li> 685<li><code>connectionListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Automatically set as a listener for the 686<a href="#event-connection"><code>'connection'</code></a> event.</li> 687<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 688</ul> 689<p><code>net.Server</code> is an <a href="events.html#class-eventemitter"><code>EventEmitter</code></a> with the following events:</p> 690<h4>Event: <code>'close'</code><span><a class="mark" href="#event-close" id="event-close">#</a></span><a aria-hidden="true" class="legacy" id="net_event_close"></a></h4> 691<div class="api_metadata"> 692<span>Added in: v0.5.0</span> 693</div> 694<p>Emitted when the server closes. If connections exist, this 695event is not emitted until all connections are ended.</p> 696<h4>Event: <code>'connection'</code><span><a class="mark" href="#event-connection" id="event-connection">#</a></span><a aria-hidden="true" class="legacy" id="net_event_connection"></a></h4> 697<div class="api_metadata"> 698<span>Added in: v0.1.90</span> 699</div> 700<ul> 701<li><a href="net.html#class-netsocket" class="type"><net.Socket></a> The connection object</li> 702</ul> 703<p>Emitted when a new connection is made. <code>socket</code> is an instance of 704<code>net.Socket</code>.</p> 705<h4>Event: <code>'error'</code><span><a class="mark" href="#event-error" id="event-error">#</a></span><a aria-hidden="true" class="legacy" id="net_event_error"></a></h4> 706<div class="api_metadata"> 707<span>Added in: v0.1.90</span> 708</div> 709<ul> 710<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type"><Error></a></li> 711</ul> 712<p>Emitted when an error occurs. Unlike <a href="#class-netsocket"><code>net.Socket</code></a>, the <a href="#event-close"><code>'close'</code></a> 713event will <strong>not</strong> be emitted directly following this event unless 714<a href="#serverclosecallback"><code>server.close()</code></a> is manually called. See the example in discussion of 715<a href="#serverlisten"><code>server.listen()</code></a>.</p> 716<h4>Event: <code>'listening'</code><span><a class="mark" href="#event-listening" id="event-listening">#</a></span><a aria-hidden="true" class="legacy" id="net_event_listening"></a></h4> 717<div class="api_metadata"> 718<span>Added in: v0.1.90</span> 719</div> 720<p>Emitted when the server has been bound after calling <a href="#serverlisten"><code>server.listen()</code></a>.</p> 721<h4>Event: <code>'drop'</code><span><a class="mark" href="#event-drop" id="event-drop">#</a></span><a aria-hidden="true" class="legacy" id="net_event_drop"></a></h4> 722<div class="api_metadata"> 723<span>Added in: v18.6.0</span> 724</div> 725<p>When the number of connections reaches the threshold of <code>server.maxConnections</code>, 726the server will drop new connections and emit <code>'drop'</code> event instead. If it is a 727TCP server, the argument is as follows, otherwise the argument is <code>undefined</code>.</p> 728<ul> 729<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> The argument passed to event listener. 730<ul> 731<li><code>localAddress</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Local address.</li> 732<li><code>localPort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Local port.</li> 733<li><code>localFamily</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Local family.</li> 734<li><code>remoteAddress</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Remote address.</li> 735<li><code>remotePort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Remote port.</li> 736<li><code>remoteFamily</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Remote IP family. <code>'IPv4'</code> or <code>'IPv6'</code>.</li> 737</ul> 738</li> 739</ul> 740<h4><code>server.address()</code><span><a class="mark" href="#serveraddress" id="serveraddress">#</a></span><a aria-hidden="true" class="legacy" id="net_server_address"></a></h4> 741<div class="api_metadata"> 742<details class="changelog"><summary>History</summary> 743<table> 744<tbody><tr><th>Version</th><th>Changes</th></tr> 745<tr><td>v18.4.0</td> 746<td><p>The <code>family</code> property now returns a string instead of a number.</p></td></tr> 747<tr><td>v18.0.0</td> 748<td><p>The <code>family</code> property now returns a number instead of a string.</p></td></tr> 749<tr><td>v0.1.90</td> 750<td><p><span>Added in: v0.1.90</span></p></td></tr> 751</tbody></table> 752</details> 753</div> 754<ul> 755<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Null_type" class="type"><null></a></li> 756</ul> 757<p>Returns the bound <code>address</code>, the address <code>family</code> name, and <code>port</code> of the server 758as reported by the operating system if listening on an IP socket 759(useful to find which port was assigned when getting an OS-assigned address): 760<code>{ port: 12346, family: 'IPv4', address: '127.0.0.1' }</code>.</p> 761<p>For a server listening on a pipe or Unix domain socket, the name is returned 762as a string.</p> 763<pre><code class="language-js"><span class="hljs-keyword">const</span> server = net.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">socket</span>) =></span> { 764 socket.<span class="hljs-title function_">end</span>(<span class="hljs-string">'goodbye\n'</span>); 765}).<span class="hljs-title function_">on</span>(<span class="hljs-string">'error'</span>, <span class="hljs-function">(<span class="hljs-params">err</span>) =></span> { 766 <span class="hljs-comment">// Handle errors here.</span> 767 <span class="hljs-keyword">throw</span> err; 768}); 769 770<span class="hljs-comment">// Grab an arbitrary unused port.</span> 771server.<span class="hljs-title function_">listen</span>(<span class="hljs-function">() =></span> { 772 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'opened server on'</span>, server.<span class="hljs-title function_">address</span>()); 773});</code> <button class="copy-button">copy</button></pre> 774<p><code>server.address()</code> returns <code>null</code> before the <code>'listening'</code> event has been 775emitted or after calling <code>server.close()</code>.</p> 776<h4><code>server.close([callback])</code><span><a class="mark" href="#serverclosecallback" id="serverclosecallback">#</a></span><a aria-hidden="true" class="legacy" id="net_server_close_callback"></a></h4> 777<div class="api_metadata"> 778<span>Added in: v0.1.90</span> 779</div> 780<ul> 781<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Called when the server is closed.</li> 782<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 783</ul> 784<p>Stops the server from accepting new connections and keeps existing 785connections. This function is asynchronous, the server is finally closed 786when all connections are ended and the server emits a <a href="#event-close"><code>'close'</code></a> event. 787The optional <code>callback</code> will be called once the <code>'close'</code> event occurs. Unlike 788that event, it will be called with an <code>Error</code> as its only argument if the server 789was not open when it was closed.</p> 790<h4><code>server[Symbol.asyncDispose]()</code><span><a class="mark" href="#serversymbolasyncdispose" id="serversymbolasyncdispose">#</a></span><a aria-hidden="true" class="legacy" id="net_server_symbol_asyncdispose"></a></h4> 791<div class="api_metadata"> 792<span>Added in: v18.18.0</span> 793</div> 794<p></p><div class="api_stability api_stability_1"><a href="documentation.html#stability-index">Stability: 1</a> - Experimental</div><p></p> 795<p>Calls <a href="#serverclosecallback"><code>server.close()</code></a> and returns a promise that fulfills when the 796server has closed.</p> 797<h4><code>server.getConnections(callback)</code><span><a class="mark" href="#servergetconnectionscallback" id="servergetconnectionscallback">#</a></span><a aria-hidden="true" class="legacy" id="net_server_getconnections_callback"></a></h4> 798<div class="api_metadata"> 799<span>Added in: v0.9.7</span> 800</div> 801<ul> 802<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> 803<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 804</ul> 805<p>Asynchronously get the number of concurrent connections on the server. Works 806when sockets were sent to forks.</p> 807<p>Callback should take two arguments <code>err</code> and <code>count</code>.</p> 808<h4><code>server.listen()</code><span><a class="mark" href="#serverlisten" id="serverlisten">#</a></span><a aria-hidden="true" class="legacy" id="net_server_listen"></a></h4> 809<p>Start a server listening for connections. A <code>net.Server</code> can be a TCP or 810an <a href="#ipc-support">IPC</a> server depending on what it listens to.</p> 811<p>Possible signatures:</p> 812<ul> 813<li><a href="#serverlistenhandle-backlog-callback"><code>server.listen(handle[, backlog][, callback])</code></a></li> 814<li><a href="#serverlistenoptions-callback"><code>server.listen(options[, callback])</code></a></li> 815<li><a href="#serverlistenpath-backlog-callback"><code>server.listen(path[, backlog][, callback])</code></a> 816for <a href="#ipc-support">IPC</a> servers</li> 817<li><a href="#serverlistenport-host-backlog-callback"><code>server.listen([port[, host[, backlog]]][, callback])</code></a> 818for TCP servers</li> 819</ul> 820<p>This function is asynchronous. When the server starts listening, the 821<a href="#event-listening"><code>'listening'</code></a> event will be emitted. The last parameter <code>callback</code> 822will be added as a listener for the <a href="#event-listening"><code>'listening'</code></a> event.</p> 823<p>All <code>listen()</code> methods can take a <code>backlog</code> parameter to specify the maximum 824length of the queue of pending connections. The actual length will be determined 825by the OS through sysctl settings such as <code>tcp_max_syn_backlog</code> and <code>somaxconn</code> 826on Linux. The default value of this parameter is 511 (not 512).</p> 827<p>All <a href="#class-netsocket"><code>net.Socket</code></a> are set to <code>SO_REUSEADDR</code> (see <a href="https://man7.org/linux/man-pages/man7/socket.7.html"><code>socket(7)</code></a> for 828details).</p> 829<p>The <code>server.listen()</code> method can be called again if and only if there was an 830error during the first <code>server.listen()</code> call or <code>server.close()</code> has been 831called. Otherwise, an <code>ERR_SERVER_ALREADY_LISTEN</code> error will be thrown.</p> 832<p>One of the most common errors raised when listening is <code>EADDRINUSE</code>. 833This happens when another server is already listening on the requested 834<code>port</code>/<code>path</code>/<code>handle</code>. One way to handle this would be to retry 835after a certain amount of time:</p> 836<pre><code class="language-js">server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'error'</span>, <span class="hljs-function">(<span class="hljs-params">e</span>) =></span> { 837 <span class="hljs-keyword">if</span> (e.<span class="hljs-property">code</span> === <span class="hljs-string">'EADDRINUSE'</span>) { 838 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'Address in use, retrying...'</span>); 839 <span class="hljs-built_in">setTimeout</span>(<span class="hljs-function">() =></span> { 840 server.<span class="hljs-title function_">close</span>(); 841 server.<span class="hljs-title function_">listen</span>(<span class="hljs-variable constant_">PORT</span>, <span class="hljs-variable constant_">HOST</span>); 842 }, <span class="hljs-number">1000</span>); 843 } 844});</code> <button class="copy-button">copy</button></pre> 845<h5><code>server.listen(handle[, backlog][, callback])</code><span><a class="mark" href="#serverlistenhandle-backlog-callback" id="serverlistenhandle-backlog-callback">#</a></span><a aria-hidden="true" class="legacy" id="net_server_listen_handle_backlog_callback"></a></h5> 846<div class="api_metadata"> 847<span>Added in: v0.5.10</span> 848</div> 849<ul> 850<li><code>handle</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a></li> 851<li><code>backlog</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Common parameter of <a href="#serverlisten"><code>server.listen()</code></a> functions</li> 852<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> 853<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 854</ul> 855<p>Start a server listening for connections on a given <code>handle</code> that has 856already been bound to a port, a Unix domain socket, or a Windows named pipe.</p> 857<p>The <code>handle</code> object can be either a server, a socket (anything with an 858underlying <code>_handle</code> member), or an object with an <code>fd</code> member that is a 859valid file descriptor.</p> 860<p>Listening on a file descriptor is not supported on Windows.</p> 861<h5><code>server.listen(options[, callback])</code><span><a class="mark" href="#serverlistenoptions-callback" id="serverlistenoptions-callback">#</a></span><a aria-hidden="true" class="legacy" id="net_server_listen_options_callback"></a></h5> 862<div class="api_metadata"> 863<details class="changelog"><summary>History</summary> 864<table> 865<tbody><tr><th>Version</th><th>Changes</th></tr> 866<tr><td>v15.6.0</td> 867<td><p>AbortSignal support was added.</p></td></tr> 868<tr><td>v11.4.0</td> 869<td><p>The <code>ipv6Only</code> option is supported.</p></td></tr> 870<tr><td>v0.11.14</td> 871<td><p><span>Added in: v0.11.14</span></p></td></tr> 872</tbody></table> 873</details> 874</div> 875<ul> 876<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> Required. Supports the following properties: 877<ul> 878<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 879<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 880<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Will be ignored if <code>port</code> is specified. See 881<a href="#identifying-paths-for-ipc-connections">Identifying paths for IPC connections</a>.</li> 882<li><code>backlog</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Common parameter of <a href="#serverlisten"><code>server.listen()</code></a> 883functions.</li> 884<li><code>exclusive</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <strong>Default:</strong> <code>false</code></li> 885<li><code>readableAll</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> For IPC servers makes the pipe readable 886for all users. <strong>Default:</strong> <code>false</code>.</li> 887<li><code>writableAll</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> For IPC servers makes the pipe writable 888for all users. <strong>Default:</strong> <code>false</code>.</li> 889<li><code>ipv6Only</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> For TCP servers, setting <code>ipv6Only</code> to <code>true</code> will 890disable dual-stack support, i.e., binding to host <code>::</code> won't make 891<code>0.0.0.0</code> be bound. <strong>Default:</strong> <code>false</code>.</li> 892<li><code>signal</code> <a href="globals.html#class-abortsignal" class="type"><AbortSignal></a> An AbortSignal that may be used to close a listening server.</li> 893</ul> 894</li> 895<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> 896functions.</li> 897<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 898</ul> 899<p>If <code>port</code> is specified, it behaves the same as 900<a href="#serverlistenport-host-backlog-callback"><code>server.listen([port[, host[, backlog]]][, callback])</code></a>. 901Otherwise, if <code>path</code> is specified, it behaves the same as 902<a href="#serverlistenpath-backlog-callback"><code>server.listen(path[, backlog][, callback])</code></a>. 903If none of them is specified, an error will be thrown.</p> 904<p>If <code>exclusive</code> is <code>false</code> (default), then cluster workers will use the same 905underlying handle, allowing connection handling duties to be shared. When 906<code>exclusive</code> is <code>true</code>, the handle is not shared, and attempted port sharing 907results in an error. An example which listens on an exclusive port is 908shown below.</p> 909<pre><code class="language-js">server.<span class="hljs-title function_">listen</span>({ 910 <span class="hljs-attr">host</span>: <span class="hljs-string">'localhost'</span>, 911 <span class="hljs-attr">port</span>: <span class="hljs-number">80</span>, 912 <span class="hljs-attr">exclusive</span>: <span class="hljs-literal">true</span>, 913});</code> <button class="copy-button">copy</button></pre> 914<p>When <code>exclusive</code> is <code>true</code> and the underlying handle is shared, it is 915possible that several workers query a handle with different backlogs. 916In this case, the first <code>backlog</code> passed to the master process will be used.</p> 917<p>Starting an IPC server as root may cause the server path to be inaccessible for 918unprivileged users. Using <code>readableAll</code> and <code>writableAll</code> will make the server 919accessible for all users.</p> 920<p>If the <code>signal</code> option is enabled, calling <code>.abort()</code> on the corresponding 921<code>AbortController</code> is similar to calling <code>.close()</code> on the server:</p> 922<pre><code class="language-js"><span class="hljs-keyword">const</span> controller = <span class="hljs-keyword">new</span> <span class="hljs-title class_">AbortController</span>(); 923server.<span class="hljs-title function_">listen</span>({ 924 <span class="hljs-attr">host</span>: <span class="hljs-string">'localhost'</span>, 925 <span class="hljs-attr">port</span>: <span class="hljs-number">80</span>, 926 <span class="hljs-attr">signal</span>: controller.<span class="hljs-property">signal</span>, 927}); 928<span class="hljs-comment">// Later, when you want to close the server.</span> 929controller.<span class="hljs-title function_">abort</span>();</code> <button class="copy-button">copy</button></pre> 930<h5><code>server.listen(path[, backlog][, callback])</code><span><a class="mark" href="#serverlistenpath-backlog-callback" id="serverlistenpath-backlog-callback">#</a></span><a aria-hidden="true" class="legacy" id="net_server_listen_path_backlog_callback"></a></h5> 931<div class="api_metadata"> 932<span>Added in: v0.1.90</span> 933</div> 934<ul> 935<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Path the server should listen to. See 936<a href="#identifying-paths-for-ipc-connections">Identifying paths for IPC connections</a>.</li> 937<li><code>backlog</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Common parameter of <a href="#serverlisten"><code>server.listen()</code></a> functions.</li> 938<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a>.</li> 939<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 940</ul> 941<p>Start an <a href="#ipc-support">IPC</a> server listening for connections on the given <code>path</code>.</p> 942<h5><code>server.listen([port[, host[, backlog]]][, callback])</code><span><a class="mark" href="#serverlistenport-host-backlog-callback" id="serverlistenport-host-backlog-callback">#</a></span><a aria-hidden="true" class="legacy" id="net_server_listen_port_host_backlog_callback"></a></h5> 943<div class="api_metadata"> 944<span>Added in: v0.1.90</span> 945</div> 946<ul> 947<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 948<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 949<li><code>backlog</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Common parameter of <a href="#serverlisten"><code>server.listen()</code></a> functions.</li> 950<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a>.</li> 951<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 952</ul> 953<p>Start a TCP server listening for connections on the given <code>port</code> and <code>host</code>.</p> 954<p>If <code>port</code> is omitted or is 0, the operating system will assign an arbitrary 955unused port, which can be retrieved by using <code>server.address().port</code> 956after the <a href="#event-listening"><code>'listening'</code></a> event has been emitted.</p> 957<p>If <code>host</code> is omitted, the server will accept connections on the 958<a href="https://en.wikipedia.org/wiki/IPv6_address#Unspecified_address">unspecified IPv6 address</a> (<code>::</code>) when IPv6 is available, or the 959<a href="https://en.wikipedia.org/wiki/0.0.0.0">unspecified IPv4 address</a> (<code>0.0.0.0</code>) otherwise.</p> 960<p>In most operating systems, listening to the <a href="https://en.wikipedia.org/wiki/IPv6_address#Unspecified_address">unspecified IPv6 address</a> (<code>::</code>) 961may cause the <code>net.Server</code> to also listen on the <a href="https://en.wikipedia.org/wiki/0.0.0.0">unspecified IPv4 address</a> 962(<code>0.0.0.0</code>).</p> 963<h4><code>server.listening</code><span><a class="mark" href="#serverlistening" id="serverlistening">#</a></span><a aria-hidden="true" class="legacy" id="net_server_listening"></a></h4> 964<div class="api_metadata"> 965<span>Added in: v5.7.0</span> 966</div> 967<ul> 968<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> Indicates whether or not the server is listening for connections.</li> 969</ul> 970<h4><code>server.maxConnections</code><span><a class="mark" href="#servermaxconnections" id="servermaxconnections">#</a></span><a aria-hidden="true" class="legacy" id="net_server_maxconnections"></a></h4> 971<div class="api_metadata"> 972<span>Added in: v0.2.0</span> 973</div> 974<ul> 975<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li> 976</ul> 977<p>Set this property to reject connections when the server's connection count gets 978high.</p> 979<p>It is not recommended to use this option once a socket has been sent to a child 980with <a href="child_process.html#child_processforkmodulepath-args-options"><code>child_process.fork()</code></a>.</p> 981<h4><code>server.ref()</code><span><a class="mark" href="#serverref" id="serverref">#</a></span><a aria-hidden="true" class="legacy" id="net_server_ref"></a></h4> 982<div class="api_metadata"> 983<span>Added in: v0.9.1</span> 984</div> 985<ul> 986<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 987</ul> 988<p>Opposite of <code>unref()</code>, calling <code>ref()</code> on a previously <code>unref</code>ed server will 989<em>not</em> let the program exit if it's the only server left (the default behavior). 990If the server is <code>ref</code>ed calling <code>ref()</code> again will have no effect.</p> 991<h4><code>server.unref()</code><span><a class="mark" href="#serverunref" id="serverunref">#</a></span><a aria-hidden="true" class="legacy" id="net_server_unref"></a></h4> 992<div class="api_metadata"> 993<span>Added in: v0.9.1</span> 994</div> 995<ul> 996<li>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></li> 997</ul> 998<p>Calling <code>unref()</code> on a server will allow the program to exit if this is the only 999active server in the event system. If the server is already <code>unref</code>ed calling 1000<code>unref()</code> again will have no effect.</p> 1001</section><section><h3>Class: <code>net.Socket</code><span><a class="mark" href="#class-netsocket" id="class-netsocket">#</a></span><a aria-hidden="true" class="legacy" id="net_class_net_socket"></a></h3> 1002<div class="api_metadata"> 1003<span>Added in: v0.3.4</span> 1004</div> 1005<ul> 1006<li>Extends: <a href="stream.html#class-streamduplex" class="type"><stream.Duplex></a></li> 1007</ul> 1008<p>This class is an abstraction of a TCP socket or a streaming <a href="#ipc-support">IPC</a> endpoint 1009(uses named pipes on Windows, and Unix domain sockets otherwise). It is also 1010an <a href="events.html#class-eventemitter"><code>EventEmitter</code></a>.</p> 1011<p>A <code>net.Socket</code> can be created by the user and used directly to interact with 1012a server. For example, it is returned by <a href="#netcreateconnection"><code>net.createConnection()</code></a>, 1013so the user can use it to talk to the server.</p> 1014<p>It can also be created by Node.js and passed to the user when a connection 1015is received. For example, it is passed to the listeners of a 1016<a href="#event-connection"><code>'connection'</code></a> event emitted on a <a href="#class-netserver"><code>net.Server</code></a>, so the user can use 1017it to interact with the client.</p> 1018<h4><code>new net.Socket([options])</code><span><a class="mark" href="#new-netsocketoptions" id="new-netsocketoptions">#</a></span><a aria-hidden="true" class="legacy" id="net_new_net_socket_options"></a></h4> 1019<div class="api_metadata"> 1020<details class="changelog"><summary>History</summary> 1021<table> 1022<tbody><tr><th>Version</th><th>Changes</th></tr> 1023<tr><td>v15.14.0</td> 1024<td><p>AbortSignal support was added.</p></td></tr> 1025<tr><td>v0.3.4</td> 1026<td><p><span>Added in: v0.3.4</span></p></td></tr> 1027</tbody></table> 1028</details> 1029</div> 1030<ul> 1031<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> Available options are: 1032<ul> 1033<li><code>fd</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> If specified, wrap around an existing socket with 1034the given file descriptor, otherwise a new socket will be created.</li> 1035<li><code>allowHalfOpen</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If set to <code>false</code>, then the socket will 1036automatically end the writable side when the readable side ends. See 1037<a href="#netcreateserveroptions-connectionlistener"><code>net.createServer()</code></a> and the <a href="#event-end"><code>'end'</code></a> event for details. <strong>Default:</strong> 1038<code>false</code>.</li> 1039<li><code>readable</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> Allow reads on the socket when an <code>fd</code> is passed, 1040otherwise ignored. <strong>Default:</strong> <code>false</code>.</li> 1041<li><code>writable</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> Allow writes on the socket when an <code>fd</code> is passed, 1042otherwise ignored. <strong>Default:</strong> <code>false</code>.</li> 1043<li><code>signal</code> <a href="globals.html#class-abortsignal" class="type"><AbortSignal></a> An Abort signal that may be used to destroy the 1044socket.</li> 1045</ul> 1046</li> 1047<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a></li> 1048</ul> 1049<p>Creates a new socket object.</p> 1050<p>The newly created socket can be either a TCP socket or a streaming <a href="#ipc-support">IPC</a> 1051endpoint, depending on what it <a href="#socketconnect"><code>connect()</code></a> to.</p> 1052<h4>Event: <code>'close'</code><span><a class="mark" href="#event-close_1" id="event-close_1">#</a></span><a aria-hidden="true" class="legacy" id="net_event_close_1"></a></h4> 1053<div class="api_metadata"> 1054<span>Added in: v0.1.90</span> 1055</div> 1056<ul> 1057<li><code>hadError</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <code>true</code> if the socket had a transmission error.</li> 1058</ul> 1059<p>Emitted once the socket is fully closed. The argument <code>hadError</code> is a boolean 1060which says if the socket was closed due to a transmission error.</p> 1061<h4>Event: <code>'connect'</code><span><a class="mark" href="#event-connect" id="event-connect">#</a></span><a aria-hidden="true" class="legacy" id="net_event_connect"></a></h4> 1062<div class="api_metadata"> 1063<span>Added in: v0.1.90</span> 1064</div> 1065<p>Emitted when a socket connection is successfully established. 1066See <a href="#netcreateconnection"><code>net.createConnection()</code></a>.</p> 1067<h4>Event: <code>'data'</code><span><a class="mark" href="#event-data" id="event-data">#</a></span><a aria-hidden="true" class="legacy" id="net_event_data"></a></h4> 1068<div class="api_metadata"> 1069<span>Added in: v0.1.90</span> 1070</div> 1071<ul> 1072<li><a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1073</ul> 1074<p>Emitted when data is received. The argument <code>data</code> will be a <code>Buffer</code> or 1075<code>String</code>. Encoding of data is set by <a href="#socketsetencodingencoding"><code>socket.setEncoding()</code></a>.</p> 1076<p>The data will be lost if there is no listener when a <code>Socket</code> 1077emits a <code>'data'</code> event.</p> 1078<h4>Event: <code>'drain'</code><span><a class="mark" href="#event-drain" id="event-drain">#</a></span><a aria-hidden="true" class="legacy" id="net_event_drain"></a></h4> 1079<div class="api_metadata"> 1080<span>Added in: v0.1.90</span> 1081</div> 1082<p>Emitted when the write buffer becomes empty. Can be used to throttle uploads.</p> 1083<p>See also: the return values of <code>socket.write()</code>.</p> 1084<h4>Event: <code>'end'</code><span><a class="mark" href="#event-end" id="event-end">#</a></span><a aria-hidden="true" class="legacy" id="net_event_end"></a></h4> 1085<div class="api_metadata"> 1086<span>Added in: v0.1.90</span> 1087</div> 1088<p>Emitted when the other end of the socket signals the end of transmission, thus 1089ending the readable side of the socket.</p> 1090<p>By default (<code>allowHalfOpen</code> is <code>false</code>) the socket will send an end of 1091transmission packet back and destroy its file descriptor once it has written out 1092its pending write queue. However, if <code>allowHalfOpen</code> is set to <code>true</code>, the 1093socket will not automatically <a href="#socketenddata-encoding-callback"><code>end()</code></a> its writable side, 1094allowing the user to write arbitrary amounts of data. The user must call 1095<a href="#socketenddata-encoding-callback"><code>end()</code></a> explicitly to close the connection (i.e. sending a 1096FIN packet back).</p> 1097<h4>Event: <code>'error'</code><span><a class="mark" href="#event-error_1" id="event-error_1">#</a></span><a aria-hidden="true" class="legacy" id="net_event_error_1"></a></h4> 1098<div class="api_metadata"> 1099<span>Added in: v0.1.90</span> 1100</div> 1101<ul> 1102<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type"><Error></a></li> 1103</ul> 1104<p>Emitted when an error occurs. The <code>'close'</code> event will be called directly 1105following this event.</p> 1106<h4>Event: <code>'lookup'</code><span><a class="mark" href="#event-lookup" id="event-lookup">#</a></span><a aria-hidden="true" class="legacy" id="net_event_lookup"></a></h4> 1107<div class="api_metadata"> 1108<details class="changelog"><summary>History</summary> 1109<table> 1110<tbody><tr><th>Version</th><th>Changes</th></tr> 1111<tr><td>v5.10.0</td> 1112<td><p>The <code>host</code> parameter is supported now.</p></td></tr> 1113<tr><td>v0.11.3</td> 1114<td><p><span>Added in: v0.11.3</span></p></td></tr> 1115</tbody></table> 1116</details> 1117</div> 1118<p>Emitted after resolving the host name but before connecting. 1119Not applicable to Unix sockets.</p> 1120<ul> 1121<li><code>err</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type"><Error></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Null_type" class="type"><null></a> The error object. See <a href="dns.html#dnslookuphostname-options-callback"><code>dns.lookup()</code></a>.</li> 1122<li><code>address</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The IP address.</li> 1123<li><code>family</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Null_type" class="type"><null></a> The address type. See <a href="dns.html#dnslookuphostname-options-callback"><code>dns.lookup()</code></a>.</li> 1124<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The host name.</li> 1125</ul> 1126<h4>Event: <code>'ready'</code><span><a class="mark" href="#event-ready" id="event-ready">#</a></span><a aria-hidden="true" class="legacy" id="net_event_ready"></a></h4> 1127<div class="api_metadata"> 1128<span>Added in: v9.11.0</span> 1129</div> 1130<p>Emitted when a socket is ready to be used.</p> 1131<p>Triggered immediately after <code>'connect'</code>.</p> 1132<h4>Event: <code>'timeout'</code><span><a class="mark" href="#event-timeout" id="event-timeout">#</a></span><a aria-hidden="true" class="legacy" id="net_event_timeout"></a></h4> 1133<div class="api_metadata"> 1134<span>Added in: v0.1.90</span> 1135</div> 1136<p>Emitted if the socket times out from inactivity. This is only to notify that 1137the socket has been idle. The user must manually close the connection.</p> 1138<p>See also: <a href="#socketsettimeouttimeout-callback"><code>socket.setTimeout()</code></a>.</p> 1139<h4><code>socket.address()</code><span><a class="mark" href="#socketaddress" id="socketaddress">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_address"></a></h4> 1140<div class="api_metadata"> 1141<details class="changelog"><summary>History</summary> 1142<table> 1143<tbody><tr><th>Version</th><th>Changes</th></tr> 1144<tr><td>v18.4.0</td> 1145<td><p>The <code>family</code> property now returns a string instead of a number.</p></td></tr> 1146<tr><td>v18.0.0</td> 1147<td><p>The <code>family</code> property now returns a number instead of a string.</p></td></tr> 1148<tr><td>v0.1.90</td> 1149<td><p><span>Added in: v0.1.90</span></p></td></tr> 1150</tbody></table> 1151</details> 1152</div> 1153<ul> 1154<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a></li> 1155</ul> 1156<p>Returns the bound <code>address</code>, the address <code>family</code> name and <code>port</code> of the 1157socket as reported by the operating system: 1158<code>{ port: 12346, family: 'IPv4', address: '127.0.0.1' }</code></p> 1159<h4><code>socket.autoSelectFamilyAttemptedAddresses</code><span><a class="mark" href="#socketautoselectfamilyattemptedaddresses" id="socketautoselectfamilyattemptedaddresses">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_autoselectfamilyattemptedaddresses"></a></h4> 1160<div class="api_metadata"> 1161<span>Added in: v18.18.0</span> 1162</div> 1163<ul> 1164<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string[]></a></li> 1165</ul> 1166<p>This property is only present if the family autoselection algorithm is enabled in 1167<a href="#socketconnectoptions-connectlistener"><code>socket.connect(options)</code></a> and it is an array of the addresses that have been attempted.</p> 1168<p>Each address is a string in the form of <code>$IP:$PORT</code>. If the connection was successful, 1169then the last address is the one that the socket is currently connected to.</p> 1170<h4><code>socket.bufferSize</code><span><a class="mark" href="#socketbuffersize" id="socketbuffersize">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_buffersize"></a></h4> 1171<div class="api_metadata"> 1172<span>Added in: v0.3.8</span><span>Deprecated since: v14.6.0</span> 1173</div> 1174<p></p><div class="api_stability api_stability_0"><a href="documentation.html#stability-index">Stability: 0</a> - Deprecated: Use <a href="stream.html#writablewritablelength"><code>writable.writableLength</code></a> instead.</div><p></p> 1175<ul> 1176<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li> 1177</ul> 1178<p>This property shows the number of characters buffered for writing. The buffer 1179may contain strings whose length after encoding is not yet known. So this number 1180is only an approximation of the number of bytes in the buffer.</p> 1181<p><code>net.Socket</code> has the property that <code>socket.write()</code> always works. This is to 1182help users get up and running quickly. The computer cannot always keep up 1183with the amount of data that is written to a socket. The network connection 1184simply might be too slow. Node.js will internally queue up the data written to a 1185socket and send it out over the wire when it is possible.</p> 1186<p>The consequence of this internal buffering is that memory may grow. 1187Users who experience large or growing <code>bufferSize</code> should attempt to 1188"throttle" the data flows in their program with 1189<a href="#socketpause"><code>socket.pause()</code></a> and <a href="#socketresume"><code>socket.resume()</code></a>.</p> 1190<h4><code>socket.bytesRead</code><span><a class="mark" href="#socketbytesread" id="socketbytesread">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_bytesread"></a></h4> 1191<div class="api_metadata"> 1192<span>Added in: v0.5.3</span> 1193</div> 1194<ul> 1195<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li> 1196</ul> 1197<p>The amount of received bytes.</p> 1198<h4><code>socket.bytesWritten</code><span><a class="mark" href="#socketbyteswritten" id="socketbyteswritten">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_byteswritten"></a></h4> 1199<div class="api_metadata"> 1200<span>Added in: v0.5.3</span> 1201</div> 1202<ul> 1203<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li> 1204</ul> 1205<p>The amount of bytes sent.</p> 1206<h4><code>socket.connect()</code><span><a class="mark" href="#socketconnect" id="socketconnect">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_connect"></a></h4> 1207<p>Initiate a connection on a given socket.</p> 1208<p>Possible signatures:</p> 1209<ul> 1210<li><a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a></li> 1211<li><a href="#socketconnectpath-connectlistener"><code>socket.connect(path[, connectListener])</code></a> 1212for <a href="#ipc-support">IPC</a> connections.</li> 1213<li><a href="#socketconnectport-host-connectlistener"><code>socket.connect(port[, host][, connectListener])</code></a> 1214for TCP connections.</li> 1215<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1216</ul> 1217<p>This function is asynchronous. When the connection is established, the 1218<a href="#event-connect"><code>'connect'</code></a> event will be emitted. If there is a problem connecting, 1219instead of a <a href="#event-connect"><code>'connect'</code></a> event, an <a href="#event-error_1"><code>'error'</code></a> event will be emitted with 1220the error passed to the <a href="#event-error_1"><code>'error'</code></a> listener. 1221The last parameter <code>connectListener</code>, if supplied, will be added as a listener 1222for the <a href="#event-connect"><code>'connect'</code></a> event <strong>once</strong>.</p> 1223<p>This function should only be used for reconnecting a socket after 1224<code>'close'</code> has been emitted or otherwise it may lead to undefined 1225behavior.</p> 1226<h5><code>socket.connect(options[, connectListener])</code><span><a class="mark" href="#socketconnectoptions-connectlistener" id="socketconnectoptions-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_connect_options_connectlistener"></a></h5> 1227<div class="api_metadata"> 1228<details class="changelog"><summary>History</summary> 1229<table> 1230<tbody><tr><th>Version</th><th>Changes</th></tr> 1231<tr><td>v18.18.0</td> 1232<td><p>The default value for autoSelectFamily option can be changed at runtime using <code>setDefaultAutoSelectFamily</code> or via the command line option <code>--enable-network-family-autoselection</code>.</p></td></tr> 1233<tr><td>v18.13.0</td> 1234<td><p>Added the <code>autoSelectFamily</code> option.</p></td></tr> 1235<tr><td>v17.7.0</td> 1236<td><p>The <code>noDelay</code>, <code>keepAlive</code>, and <code>keepAliveInitialDelay</code> options are supported now.</p></td></tr> 1237<tr><td>v12.10.0</td> 1238<td><p>Added <code>onread</code> option.</p></td></tr> 1239<tr><td>v6.0.0</td> 1240<td><p>The <code>hints</code> option defaults to <code>0</code> in all cases now. Previously, in the absence of the <code>family</code> option it would default to <code>dns.ADDRCONFIG | dns.V4MAPPED</code>.</p></td></tr> 1241<tr><td>v5.11.0</td> 1242<td><p>The <code>hints</code> option is supported now.</p></td></tr> 1243<tr><td>v0.1.90</td> 1244<td><p><span>Added in: v0.1.90</span></p></td></tr> 1245</tbody></table> 1246</details> 1247</div> 1248<ul> 1249<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a></li> 1250<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of <a href="#socketconnect"><code>socket.connect()</code></a> 1251methods. Will be added as a listener for the <a href="#event-connect"><code>'connect'</code></a> event once.</li> 1252<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1253</ul> 1254<p>Initiate a connection on a given socket. Normally this method is not needed, 1255the socket should be created and opened with <a href="#netcreateconnection"><code>net.createConnection()</code></a>. Use 1256this only when implementing a custom Socket.</p> 1257<p>For TCP connections, available <code>options</code> are:</p> 1258<ul> 1259<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Required. Port the socket should connect to.</li> 1260<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Host the socket should connect to. <strong>Default:</strong> <code>'localhost'</code>.</li> 1261<li><code>localAddress</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Local address the socket should connect from.</li> 1262<li><code>localPort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Local port the socket should connect from.</li> 1263<li><code>family</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a>: Version of IP stack. Must be <code>4</code>, <code>6</code>, or <code>0</code>. The value 1264<code>0</code> indicates that both IPv4 and IPv6 addresses are allowed. <strong>Default:</strong> <code>0</code>.</li> 1265<li><code>hints</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Optional <a href="dns.html#supported-getaddrinfo-flags"><code>dns.lookup()</code> hints</a>.</li> 1266<li><code>lookup</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Custom lookup function. <strong>Default:</strong> <a href="dns.html#dnslookuphostname-options-callback"><code>dns.lookup()</code></a>.</li> 1267<li><code>noDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If set to <code>true</code>, it disables the use of Nagle's algorithm immediately 1268after the socket is established. <strong>Default:</strong> <code>false</code>.</li> 1269<li><code>keepAlive</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If set to <code>true</code>, it enables keep-alive functionality on the socket 1270immediately after the connection is established, similarly on what is done in 1271<a href="#socketsetkeepaliveenable-initialdelay"><code>socket.setKeepAlive([enable][, initialDelay])</code></a>. 1272<strong>Default:</strong> <code>false</code>.</li> 1273<li><code>keepAliveInitialDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> If set to a positive number, it sets the initial delay before 1274the first keepalive probe is sent on an idle socket.<strong>Default:</strong> <code>0</code>.</li> 1275<li><code>autoSelectFamily</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a>: If set to <code>true</code>, it enables a family autodetection algorithm 1276that loosely implements section 5 of <a href="https://www.rfc-editor.org/rfc/rfc8305.txt">RFC 8305</a>. 1277The <code>all</code> option passed to lookup is set to <code>true</code> and the sockets attempts to connect to all 1278obtained IPv6 and IPv4 addresses, in sequence, until a connection is established. 1279The first returned AAAA address is tried first, then the first returned A address, 1280then the second returned AAAA address and so on. 1281Each connection attempt is given the amount of time specified by the <code>autoSelectFamilyAttemptTimeout</code> 1282option before timing out and trying the next address. 1283Ignored if the <code>family</code> option is not <code>0</code> or if <code>localAddress</code> is set. 1284Connection errors are not emitted if at least one connection succeeds. 1285<strong>Default:</strong> initially <code>false</code>, but it can be changed at runtime using <a href="#netsetdefaultautoselectfamilyvalue"><code>net.setDefaultAutoSelectFamily(value)</code></a> 1286or via the command line option <code>--enable-network-family-autoselection</code>.</li> 1287<li><code>autoSelectFamilyAttemptTimeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a>: The amount of time in milliseconds to wait 1288for a connection attempt to finish before trying the next address when using the <code>autoSelectFamily</code> option. 1289If set to a positive integer less than <code>10</code>, then the value <code>10</code> will be used instead. 1290<strong>Default:</strong> initially <code>250</code>, but it can be changed at runtime using <a href="#netsetdefaultautoselectfamilyattempttimeoutvalue"><code>net.setDefaultAutoSelectFamilyAttemptTimeout(value)</code></a></li> 1291</ul> 1292<p>For <a href="#ipc-support">IPC</a> connections, available <code>options</code> are:</p> 1293<ul> 1294<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Required. Path the client should connect to. 1295See <a href="#identifying-paths-for-ipc-connections">Identifying paths for IPC connections</a>. If provided, the TCP-specific 1296options above are ignored.</li> 1297</ul> 1298<p>For both types, available <code>options</code> include:</p> 1299<ul> 1300<li><code>onread</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> If specified, incoming data is stored in a single <code>buffer</code> 1301and passed to the supplied <code>callback</code> when data arrives on the socket. 1302This will cause the streaming functionality to not provide any data. 1303The socket will emit events like <code>'error'</code>, <code>'end'</code>, and <code>'close'</code> 1304as usual. Methods like <code>pause()</code> and <code>resume()</code> will also behave as 1305expected. 1306<ul> 1307<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array" class="type"><Uint8Array></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Either a reusable chunk of memory to 1308use for storing incoming data or a function that returns such.</li> 1309<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> This function is called for every chunk of incoming 1310data. Two arguments are passed to it: the number of bytes written to 1311<code>buffer</code> and a reference to <code>buffer</code>. Return <code>false</code> from this function to 1312implicitly <code>pause()</code> the socket. This function will be executed in the 1313global context.</li> 1314</ul> 1315</li> 1316</ul> 1317<p>Following is an example of a client using the <code>onread</code> option:</p> 1318<pre><code class="language-js"><span class="hljs-keyword">const</span> net = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:net'</span>); 1319net.<span class="hljs-title function_">connect</span>({ 1320 <span class="hljs-attr">port</span>: <span class="hljs-number">80</span>, 1321 <span class="hljs-attr">onread</span>: { 1322 <span class="hljs-comment">// Reuses a 4KiB Buffer for every read from the socket.</span> 1323 <span class="hljs-attr">buffer</span>: <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">alloc</span>(<span class="hljs-number">4</span> * <span class="hljs-number">1024</span>), 1324 <span class="hljs-attr">callback</span>: <span class="hljs-keyword">function</span>(<span class="hljs-params">nread, buf</span>) { 1325 <span class="hljs-comment">// Received data is available in `buf` from 0 to `nread`.</span> 1326 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(buf.<span class="hljs-title function_">toString</span>(<span class="hljs-string">'utf8'</span>, <span class="hljs-number">0</span>, nread)); 1327 }, 1328 }, 1329});</code> <button class="copy-button">copy</button></pre> 1330<h5><code>socket.connect(path[, connectListener])</code><span><a class="mark" href="#socketconnectpath-connectlistener" id="socketconnectpath-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_connect_path_connectlistener"></a></h5> 1331<ul> 1332<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Path the client should connect to. See 1333<a href="#identifying-paths-for-ipc-connections">Identifying paths for IPC connections</a>.</li> 1334<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of <a href="#socketconnect"><code>socket.connect()</code></a> 1335methods. Will be added as a listener for the <a href="#event-connect"><code>'connect'</code></a> event once.</li> 1336<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1337</ul> 1338<p>Initiate an <a href="#ipc-support">IPC</a> connection on the given socket.</p> 1339<p>Alias to 1340<a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a> 1341called with <code>{ path: path }</code> as <code>options</code>.</p> 1342<h5><code>socket.connect(port[, host][, connectListener])</code><span><a class="mark" href="#socketconnectport-host-connectlistener" id="socketconnectport-host-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_connect_port_host_connectlistener"></a></h5> 1343<div class="api_metadata"> 1344<span>Added in: v0.1.90</span> 1345</div> 1346<ul> 1347<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Port the client should connect to.</li> 1348<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Host the client should connect to.</li> 1349<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of <a href="#socketconnect"><code>socket.connect()</code></a> 1350methods. Will be added as a listener for the <a href="#event-connect"><code>'connect'</code></a> event once.</li> 1351<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1352</ul> 1353<p>Initiate a TCP connection on the given socket.</p> 1354<p>Alias to 1355<a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a> 1356called with <code>{port: port, host: host}</code> as <code>options</code>.</p> 1357<h4><code>socket.connecting</code><span><a class="mark" href="#socketconnecting" id="socketconnecting">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_connecting"></a></h4> 1358<div class="api_metadata"> 1359<span>Added in: v6.1.0</span> 1360</div> 1361<ul> 1362<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1363</ul> 1364<p>If <code>true</code>, 1365<a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a> was 1366called and has not yet finished. It will stay <code>true</code> until the socket becomes 1367connected, then it is set to <code>false</code> and the <code>'connect'</code> event is emitted. Note 1368that the 1369<a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a> 1370callback is a listener for the <code>'connect'</code> event.</p> 1371<h4><code>socket.destroy([error])</code><span><a class="mark" href="#socketdestroyerror" id="socketdestroyerror">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_destroy_error"></a></h4> 1372<div class="api_metadata"> 1373<span>Added in: v0.1.90</span> 1374</div> 1375<ul> 1376<li><code>error</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a></li> 1377<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a></li> 1378</ul> 1379<p>Ensures that no more I/O activity happens on this socket. 1380Destroys the stream and closes the connection.</p> 1381<p>See <a href="stream.html#writabledestroyerror"><code>writable.destroy()</code></a> for further details.</p> 1382<h4><code>socket.destroyed</code><span><a class="mark" href="#socketdestroyed" id="socketdestroyed">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_destroyed"></a></h4> 1383<ul> 1384<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> Indicates if the connection is destroyed or not. Once a 1385connection is destroyed no further data can be transferred using it.</li> 1386</ul> 1387<p>See <a href="stream.html#writabledestroyed"><code>writable.destroyed</code></a> for further details.</p> 1388<h4><code>socket.destroySoon()</code><span><a class="mark" href="#socketdestroysoon" id="socketdestroysoon">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_destroysoon"></a></h4> 1389<div class="api_metadata"> 1390<span>Added in: v0.3.4</span> 1391</div> 1392<p>Destroys the socket after all data is written. If the <code>'finish'</code> event was 1393already emitted the socket is destroyed immediately. If the socket is still 1394writable it implicitly calls <code>socket.end()</code>.</p> 1395<h4><code>socket.end([data[, encoding]][, callback])</code><span><a class="mark" href="#socketenddata-encoding-callback" id="socketenddata-encoding-callback">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_end_data_encoding_callback"></a></h4> 1396<div class="api_metadata"> 1397<span>Added in: v0.1.90</span> 1398</div> 1399<ul> 1400<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array" class="type"><Uint8Array></a></li> 1401<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Only used when data is <code>string</code>. <strong>Default:</strong> <code>'utf8'</code>.</li> 1402<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Optional callback for when the socket is finished.</li> 1403<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1404</ul> 1405<p>Half-closes the socket. i.e., it sends a FIN packet. It is possible the 1406server will still send some data.</p> 1407<p>See <a href="stream.html#writableendchunk-encoding-callback"><code>writable.end()</code></a> for further details.</p> 1408<h4><code>socket.localAddress</code><span><a class="mark" href="#socketlocaladdress" id="socketlocaladdress">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_localaddress"></a></h4> 1409<div class="api_metadata"> 1410<span>Added in: v0.9.6</span> 1411</div> 1412<ul> 1413<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1414</ul> 1415<p>The string representation of the local IP address the remote client is 1416connecting on. For example, in a server listening on <code>'0.0.0.0'</code>, if a client 1417connects on <code>'192.168.1.1'</code>, the value of <code>socket.localAddress</code> would be 1418<code>'192.168.1.1'</code>.</p> 1419<h4><code>socket.localPort</code><span><a class="mark" href="#socketlocalport" id="socketlocalport">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_localport"></a></h4> 1420<div class="api_metadata"> 1421<span>Added in: v0.9.6</span> 1422</div> 1423<ul> 1424<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li> 1425</ul> 1426<p>The numeric representation of the local port. For example, <code>80</code> or <code>21</code>.</p> 1427<h4><code>socket.localFamily</code><span><a class="mark" href="#socketlocalfamily" id="socketlocalfamily">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_localfamily"></a></h4> 1428<div class="api_metadata"> 1429<span>Added in: v18.8.0</span> 1430</div> 1431<ul> 1432<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1433</ul> 1434<p>The string representation of the local IP family. <code>'IPv4'</code> or <code>'IPv6'</code>.</p> 1435<h4><code>socket.pause()</code><span><a class="mark" href="#socketpause" id="socketpause">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_pause"></a></h4> 1436<ul> 1437<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1438</ul> 1439<p>Pauses the reading of data. That is, <a href="#event-data"><code>'data'</code></a> events will not be emitted. 1440Useful to throttle back an upload.</p> 1441<h4><code>socket.pending</code><span><a class="mark" href="#socketpending" id="socketpending">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_pending"></a></h4> 1442<div class="api_metadata"> 1443<span>Added in: v11.2.0, v10.16.0</span> 1444</div> 1445<ul> 1446<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1447</ul> 1448<p>This is <code>true</code> if the socket is not connected yet, either because <code>.connect()</code> 1449has not yet been called or because it is still in the process of connecting 1450(see <a href="#socketconnecting"><code>socket.connecting</code></a>).</p> 1451<h4><code>socket.ref()</code><span><a class="mark" href="#socketref" id="socketref">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_ref"></a></h4> 1452<div class="api_metadata"> 1453<span>Added in: v0.9.1</span> 1454</div> 1455<ul> 1456<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1457</ul> 1458<p>Opposite of <code>unref()</code>, calling <code>ref()</code> on a previously <code>unref</code>ed socket will 1459<em>not</em> let the program exit if it's the only socket left (the default behavior). 1460If the socket is <code>ref</code>ed calling <code>ref</code> again will have no effect.</p> 1461<h4><code>socket.remoteAddress</code><span><a class="mark" href="#socketremoteaddress" id="socketremoteaddress">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_remoteaddress"></a></h4> 1462<div class="api_metadata"> 1463<span>Added in: v0.5.10</span> 1464</div> 1465<ul> 1466<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1467</ul> 1468<p>The string representation of the remote IP address. For example, 1469<code>'74.125.127.100'</code> or <code>'2001:4860:a005::68'</code>. Value may be <code>undefined</code> if 1470the socket is destroyed (for example, if the client disconnected).</p> 1471<h4><code>socket.remoteFamily</code><span><a class="mark" href="#socketremotefamily" id="socketremotefamily">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_remotefamily"></a></h4> 1472<div class="api_metadata"> 1473<span>Added in: v0.11.14</span> 1474</div> 1475<ul> 1476<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1477</ul> 1478<p>The string representation of the remote IP family. <code>'IPv4'</code> or <code>'IPv6'</code>. Value may be <code>undefined</code> if 1479the socket is destroyed (for example, if the client disconnected).</p> 1480<h4><code>socket.remotePort</code><span><a class="mark" href="#socketremoteport" id="socketremoteport">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_remoteport"></a></h4> 1481<div class="api_metadata"> 1482<span>Added in: v0.5.10</span> 1483</div> 1484<ul> 1485<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li> 1486</ul> 1487<p>The numeric representation of the remote port. For example, <code>80</code> or <code>21</code>. Value may be <code>undefined</code> if 1488the socket is destroyed (for example, if the client disconnected).</p> 1489<h4><code>socket.resetAndDestroy()</code><span><a class="mark" href="#socketresetanddestroy" id="socketresetanddestroy">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_resetanddestroy"></a></h4> 1490<div class="api_metadata"> 1491<span>Added in: v18.3.0</span> 1492</div> 1493<ul> 1494<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a></li> 1495</ul> 1496<p>Close the TCP connection by sending an RST packet and destroy the stream. 1497If this TCP socket is in connecting status, it will send an RST packet and destroy this TCP socket once it is connected. 1498Otherwise, it will call <code>socket.destroy</code> with an <code>ERR_SOCKET_CLOSED</code> Error. 1499If this is not a TCP socket (for example, a pipe), calling this method will immediately throw an <code>ERR_INVALID_HANDLE_TYPE</code> Error.</p> 1500<h4><code>socket.resume()</code><span><a class="mark" href="#socketresume" id="socketresume">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_resume"></a></h4> 1501<ul> 1502<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1503</ul> 1504<p>Resumes reading after a call to <a href="#socketpause"><code>socket.pause()</code></a>.</p> 1505<h4><code>socket.setEncoding([encoding])</code><span><a class="mark" href="#socketsetencodingencoding" id="socketsetencodingencoding">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_setencoding_encoding"></a></h4> 1506<div class="api_metadata"> 1507<span>Added in: v0.1.90</span> 1508</div> 1509<ul> 1510<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1511<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1512</ul> 1513<p>Set the encoding for the socket as a <a href="stream.html#class-streamreadable">Readable Stream</a>. See 1514<a href="stream.html#readablesetencodingencoding"><code>readable.setEncoding()</code></a> for more information.</p> 1515<h4><code>socket.setKeepAlive([enable][, initialDelay])</code><span><a class="mark" href="#socketsetkeepaliveenable-initialdelay" id="socketsetkeepaliveenable-initialdelay">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_setkeepalive_enable_initialdelay"></a></h4> 1516<div class="api_metadata"> 1517<details class="changelog"><summary>History</summary> 1518<table> 1519<tbody><tr><th>Version</th><th>Changes</th></tr> 1520<tr><td>v13.12.0, v12.17.0</td> 1521<td><p>New defaults for <code>TCP_KEEPCNT</code> and <code>TCP_KEEPINTVL</code> socket options were added.</p></td></tr> 1522<tr><td>v0.1.92</td> 1523<td><p><span>Added in: v0.1.92</span></p></td></tr> 1524</tbody></table> 1525</details> 1526</div> 1527<ul> 1528<li><code>enable</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <strong>Default:</strong> <code>false</code></li> 1529<li><code>initialDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> <strong>Default:</strong> <code>0</code></li> 1530<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1531</ul> 1532<p>Enable/disable keep-alive functionality, and optionally set the initial 1533delay before the first keepalive probe is sent on an idle socket.</p> 1534<p>Set <code>initialDelay</code> (in milliseconds) to set the delay between the last 1535data packet received and the first keepalive probe. Setting <code>0</code> for 1536<code>initialDelay</code> will leave the value unchanged from the default 1537(or previous) setting.</p> 1538<p>Enabling the keep-alive functionality will set the following socket options:</p> 1539<ul> 1540<li><code>SO_KEEPALIVE=1</code></li> 1541<li><code>TCP_KEEPIDLE=initialDelay</code></li> 1542<li><code>TCP_KEEPCNT=10</code></li> 1543<li><code>TCP_KEEPINTVL=1</code></li> 1544</ul> 1545<h4><code>socket.setNoDelay([noDelay])</code><span><a class="mark" href="#socketsetnodelaynodelay" id="socketsetnodelaynodelay">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_setnodelay_nodelay"></a></h4> 1546<div class="api_metadata"> 1547<span>Added in: v0.1.90</span> 1548</div> 1549<ul> 1550<li><code>noDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <strong>Default:</strong> <code>true</code></li> 1551<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1552</ul> 1553<p>Enable/disable the use of Nagle's algorithm.</p> 1554<p>When a TCP connection is created, it will have Nagle's algorithm enabled.</p> 1555<p>Nagle's algorithm delays data before it is sent via the network. It attempts 1556to optimize throughput at the expense of latency.</p> 1557<p>Passing <code>true</code> for <code>noDelay</code> or not passing an argument will disable Nagle's 1558algorithm for the socket. Passing <code>false</code> for <code>noDelay</code> will enable Nagle's 1559algorithm.</p> 1560<h4><code>socket.setTimeout(timeout[, callback])</code><span><a class="mark" href="#socketsettimeouttimeout-callback" id="socketsettimeouttimeout-callback">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_settimeout_timeout_callback"></a></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>v18.0.0</td> 1566<td><p>Passing an invalid callback to the <code>callback</code> argument now throws <code>ERR_INVALID_ARG_TYPE</code> instead of <code>ERR_INVALID_CALLBACK</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>timeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1574<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> 1575<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1576</ul> 1577<p>Sets the socket to timeout after <code>timeout</code> milliseconds of inactivity on 1578the socket. By default <code>net.Socket</code> do not have a timeout.</p> 1579<p>When an idle timeout is triggered the socket will receive a <a href="#event-timeout"><code>'timeout'</code></a> 1580event but the connection will not be severed. The user must manually call 1581<a href="#socketenddata-encoding-callback"><code>socket.end()</code></a> or <a href="#socketdestroyerror"><code>socket.destroy()</code></a> to end the connection.</p> 1582<pre><code class="language-js">socket.<span class="hljs-built_in">setTimeout</span>(<span class="hljs-number">3000</span>); 1583socket.<span class="hljs-title function_">on</span>(<span class="hljs-string">'timeout'</span>, <span class="hljs-function">() =></span> { 1584 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'socket timeout'</span>); 1585 socket.<span class="hljs-title function_">end</span>(); 1586});</code> <button class="copy-button">copy</button></pre> 1587<p>If <code>timeout</code> is 0, then the existing idle timeout is disabled.</p> 1588<p>The optional <code>callback</code> parameter will be added as a one-time listener for the 1589<a href="#event-timeout"><code>'timeout'</code></a> event.</p> 1590<h4><code>socket.timeout</code><span><a class="mark" href="#sockettimeout" id="sockettimeout">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_timeout"></a></h4> 1591<div class="api_metadata"> 1592<span>Added in: v10.7.0</span> 1593</div> 1594<ul> 1595<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Undefined_type" class="type"><undefined></a></li> 1596</ul> 1597<p>The socket timeout in milliseconds as set by <a href="#socketsettimeouttimeout-callback"><code>socket.setTimeout()</code></a>. 1598It is <code>undefined</code> if a timeout has not been set.</p> 1599<h4><code>socket.unref()</code><span><a class="mark" href="#socketunref" id="socketunref">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_unref"></a></h4> 1600<div class="api_metadata"> 1601<span>Added in: v0.9.1</span> 1602</div> 1603<ul> 1604<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The socket itself.</li> 1605</ul> 1606<p>Calling <code>unref()</code> on a socket will allow the program to exit if this is the only 1607active socket in the event system. If the socket is already <code>unref</code>ed calling 1608<code>unref()</code> again will have no effect.</p> 1609<h4><code>socket.write(data[, encoding][, callback])</code><span><a class="mark" href="#socketwritedata-encoding-callback" id="socketwritedata-encoding-callback">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_write_data_encoding_callback"></a></h4> 1610<div class="api_metadata"> 1611<span>Added in: v0.1.90</span> 1612</div> 1613<ul> 1614<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array" class="type"><Uint8Array></a></li> 1615<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Only used when data is <code>string</code>. <strong>Default:</strong> <code>utf8</code>.</li> 1616<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> 1617<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1618</ul> 1619<p>Sends data on the socket. The second parameter specifies the encoding in the 1620case of a string. It defaults to UTF8 encoding.</p> 1621<p>Returns <code>true</code> if the entire data was flushed successfully to the kernel 1622buffer. Returns <code>false</code> if all or part of the data was queued in user memory. 1623<a href="#event-drain"><code>'drain'</code></a> will be emitted when the buffer is again free.</p> 1624<p>The optional <code>callback</code> parameter will be executed when the data is finally 1625written out, which may not be immediately.</p> 1626<p>See <code>Writable</code> stream <a href="stream.html#writablewritechunk-encoding-callback"><code>write()</code></a> method for more 1627information.</p> 1628<h4><code>socket.readyState</code><span><a class="mark" href="#socketreadystate" id="socketreadystate">#</a></span><a aria-hidden="true" class="legacy" id="net_socket_readystate"></a></h4> 1629<div class="api_metadata"> 1630<span>Added in: v0.5.0</span> 1631</div> 1632<ul> 1633<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1634</ul> 1635<p>This property represents the state of the connection as a string.</p> 1636<ul> 1637<li>If the stream is connecting <code>socket.readyState</code> is <code>opening</code>.</li> 1638<li>If the stream is readable and writable, it is <code>open</code>.</li> 1639<li>If the stream is readable and not writable, it is <code>readOnly</code>.</li> 1640<li>If the stream is not readable and writable, it is <code>writeOnly</code>.</li> 1641</ul> 1642</section><section><h3><code>net.connect()</code><span><a class="mark" href="#netconnect" id="netconnect">#</a></span><a aria-hidden="true" class="legacy" id="net_net_connect"></a></h3> 1643<p>Aliases to 1644<a href="#netcreateconnection"><code>net.createConnection()</code></a>.</p> 1645<p>Possible signatures:</p> 1646<ul> 1647<li><a href="#netconnectoptions-connectlistener"><code>net.connect(options[, connectListener])</code></a></li> 1648<li><a href="#netconnectpath-connectlistener"><code>net.connect(path[, connectListener])</code></a> for <a href="#ipc-support">IPC</a> 1649connections.</li> 1650<li><a href="#netconnectport-host-connectlistener"><code>net.connect(port[, host][, connectListener])</code></a> 1651for TCP connections.</li> 1652</ul> 1653<h4><code>net.connect(options[, connectListener])</code><span><a class="mark" href="#netconnectoptions-connectlistener" id="netconnectoptions-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_net_connect_options_connectlistener"></a></h4> 1654<div class="api_metadata"> 1655<span>Added in: v0.7.0</span> 1656</div> 1657<ul> 1658<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a></li> 1659<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> 1660<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a></li> 1661</ul> 1662<p>Alias to 1663<a href="#netcreateconnectionoptions-connectlistener"><code>net.createConnection(options[, connectListener])</code></a>.</p> 1664<h4><code>net.connect(path[, connectListener])</code><span><a class="mark" href="#netconnectpath-connectlistener" id="netconnectpath-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_net_connect_path_connectlistener"></a></h4> 1665<div class="api_metadata"> 1666<span>Added in: v0.1.90</span> 1667</div> 1668<ul> 1669<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1670<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> 1671<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a></li> 1672</ul> 1673<p>Alias to 1674<a href="#netcreateconnectionpath-connectlistener"><code>net.createConnection(path[, connectListener])</code></a>.</p> 1675<h4><code>net.connect(port[, host][, connectListener])</code><span><a class="mark" href="#netconnectport-host-connectlistener" id="netconnectport-host-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_net_connect_port_host_connectlistener"></a></h4> 1676<div class="api_metadata"> 1677<span>Added in: v0.1.90</span> 1678</div> 1679<ul> 1680<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1681<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1682<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> 1683<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a></li> 1684</ul> 1685<p>Alias to 1686<a href="#netcreateconnectionport-host-connectlistener"><code>net.createConnection(port[, host][, connectListener])</code></a>.</p> 1687</section><section><h3><code>net.createConnection()</code><span><a class="mark" href="#netcreateconnection" id="netcreateconnection">#</a></span><a aria-hidden="true" class="legacy" id="net_net_createconnection"></a></h3> 1688<p>A factory function, which creates a new <a href="#class-netsocket"><code>net.Socket</code></a>, 1689immediately initiates connection with <a href="#socketconnect"><code>socket.connect()</code></a>, 1690then returns the <code>net.Socket</code> that starts the connection.</p> 1691<p>When the connection is established, a <a href="#event-connect"><code>'connect'</code></a> event will be emitted 1692on the returned socket. The last parameter <code>connectListener</code>, if supplied, 1693will be added as a listener for the <a href="#event-connect"><code>'connect'</code></a> event <strong>once</strong>.</p> 1694<p>Possible signatures:</p> 1695<ul> 1696<li><a href="#netcreateconnectionoptions-connectlistener"><code>net.createConnection(options[, connectListener])</code></a></li> 1697<li><a href="#netcreateconnectionpath-connectlistener"><code>net.createConnection(path[, connectListener])</code></a> 1698for <a href="#ipc-support">IPC</a> connections.</li> 1699<li><a href="#netcreateconnectionport-host-connectlistener"><code>net.createConnection(port[, host][, connectListener])</code></a> 1700for TCP connections.</li> 1701</ul> 1702<p>The <a href="#netconnect"><code>net.connect()</code></a> function is an alias to this function.</p> 1703<h4><code>net.createConnection(options[, connectListener])</code><span><a class="mark" href="#netcreateconnectionoptions-connectlistener" id="netcreateconnectionoptions-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_net_createconnection_options_connectlistener"></a></h4> 1704<div class="api_metadata"> 1705<span>Added in: v0.1.90</span> 1706</div> 1707<ul> 1708<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> Required. Will be passed to both the 1709<a href="#new-netsocketoptions"><code>new net.Socket([options])</code></a> call and the 1710<a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a> 1711method.</li> 1712<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of the 1713<a href="#netcreateconnection"><code>net.createConnection()</code></a> functions. If supplied, will be added as 1714a listener for the <a href="#event-connect"><code>'connect'</code></a> event on the returned socket once.</li> 1715<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The newly created socket used to start the connection.</li> 1716</ul> 1717<p>For available options, see 1718<a href="#new-netsocketoptions"><code>new net.Socket([options])</code></a> 1719and <a href="#socketconnectoptions-connectlistener"><code>socket.connect(options[, connectListener])</code></a>.</p> 1720<p>Additional options:</p> 1721<ul> 1722<li><code>timeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> If set, will be used to call 1723<a href="#socketsettimeouttimeout-callback"><code>socket.setTimeout(timeout)</code></a> after the socket is created, but before 1724it starts the connection.</li> 1725</ul> 1726<p>Following is an example of a client of the echo server described 1727in the <a href="#netcreateserveroptions-connectionlistener"><code>net.createServer()</code></a> section:</p> 1728<pre><code class="language-js"><span class="hljs-keyword">const</span> net = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:net'</span>); 1729<span class="hljs-keyword">const</span> client = net.<span class="hljs-title function_">createConnection</span>({ <span class="hljs-attr">port</span>: <span class="hljs-number">8124</span> }, <span class="hljs-function">() =></span> { 1730 <span class="hljs-comment">// 'connect' listener.</span> 1731 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'connected to server!'</span>); 1732 client.<span class="hljs-title function_">write</span>(<span class="hljs-string">'world!\r\n'</span>); 1733}); 1734client.<span class="hljs-title function_">on</span>(<span class="hljs-string">'data'</span>, <span class="hljs-function">(<span class="hljs-params">data</span>) =></span> { 1735 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(data.<span class="hljs-title function_">toString</span>()); 1736 client.<span class="hljs-title function_">end</span>(); 1737}); 1738client.<span class="hljs-title function_">on</span>(<span class="hljs-string">'end'</span>, <span class="hljs-function">() =></span> { 1739 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'disconnected from server'</span>); 1740});</code> <button class="copy-button">copy</button></pre> 1741<p>To connect on the socket <code>/tmp/echo.sock</code>:</p> 1742<pre><code class="language-js"><span class="hljs-keyword">const</span> client = net.<span class="hljs-title function_">createConnection</span>({ <span class="hljs-attr">path</span>: <span class="hljs-string">'/tmp/echo.sock'</span> });</code> <button class="copy-button">copy</button></pre> 1743<h4><code>net.createConnection(path[, connectListener])</code><span><a class="mark" href="#netcreateconnectionpath-connectlistener" id="netcreateconnectionpath-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_net_createconnection_path_connectlistener"></a></h4> 1744<div class="api_metadata"> 1745<span>Added in: v0.1.90</span> 1746</div> 1747<ul> 1748<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Path the socket should connect to. Will be passed to 1749<a href="#socketconnectpath-connectlistener"><code>socket.connect(path[, connectListener])</code></a>. 1750See <a href="#identifying-paths-for-ipc-connections">Identifying paths for IPC connections</a>.</li> 1751<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of the 1752<a href="#netcreateconnection"><code>net.createConnection()</code></a> functions, an "once" listener for the 1753<code>'connect'</code> event on the initiating socket. Will be passed to 1754<a href="#socketconnectpath-connectlistener"><code>socket.connect(path[, connectListener])</code></a>.</li> 1755<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The newly created socket used to start the connection.</li> 1756</ul> 1757<p>Initiates an <a href="#ipc-support">IPC</a> connection.</p> 1758<p>This function creates a new <a href="#class-netsocket"><code>net.Socket</code></a> with all options set to default, 1759immediately initiates connection with 1760<a href="#socketconnectpath-connectlistener"><code>socket.connect(path[, connectListener])</code></a>, 1761then returns the <code>net.Socket</code> that starts the connection.</p> 1762<h4><code>net.createConnection(port[, host][, connectListener])</code><span><a class="mark" href="#netcreateconnectionport-host-connectlistener" id="netcreateconnectionport-host-connectlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_net_createconnection_port_host_connectlistener"></a></h4> 1763<div class="api_metadata"> 1764<span>Added in: v0.1.90</span> 1765</div> 1766<ul> 1767<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Port the socket should connect to. Will be passed to 1768<a href="#socketconnectport-host-connectlistener"><code>socket.connect(port[, host][, connectListener])</code></a>.</li> 1769<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Host the socket should connect to. Will be passed to 1770<a href="#socketconnectport-host-connectlistener"><code>socket.connect(port[, host][, connectListener])</code></a>. 1771<strong>Default:</strong> <code>'localhost'</code>.</li> 1772<li><code>connectListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of the 1773<a href="#netcreateconnection"><code>net.createConnection()</code></a> functions, an "once" listener for the 1774<code>'connect'</code> event on the initiating socket. Will be passed to 1775<a href="#socketconnectport-host-connectlistener"><code>socket.connect(port[, host][, connectListener])</code></a>.</li> 1776<li>Returns: <a href="net.html#class-netsocket" class="type"><net.Socket></a> The newly created socket used to start the connection.</li> 1777</ul> 1778<p>Initiates a TCP connection.</p> 1779<p>This function creates a new <a href="#class-netsocket"><code>net.Socket</code></a> with all options set to default, 1780immediately initiates connection with 1781<a href="#socketconnectport-host-connectlistener"><code>socket.connect(port[, host][, connectListener])</code></a>, 1782then returns the <code>net.Socket</code> that starts the connection.</p> 1783</section><section><h3><code>net.createServer([options][, connectionListener])</code><span><a class="mark" href="#netcreateserveroptions-connectionlistener" id="netcreateserveroptions-connectionlistener">#</a></span><a aria-hidden="true" class="legacy" id="net_net_createserver_options_connectionlistener"></a></h3> 1784<div class="api_metadata"> 1785<details class="changelog"><summary>History</summary> 1786<table> 1787<tbody><tr><th>Version</th><th>Changes</th></tr> 1788<tr><td>v18.17.0</td> 1789<td><p>The <code>highWaterMark</code> option is supported now.</p></td></tr> 1790<tr><td>v17.7.0, v16.15.0</td> 1791<td><p>The <code>noDelay</code>, <code>keepAlive</code>, and <code>keepAliveInitialDelay</code> options are supported now.</p></td></tr> 1792<tr><td>v0.5.0</td> 1793<td><p><span>Added in: v0.5.0</span></p></td></tr> 1794</tbody></table> 1795</details> 1796</div> 1797<ul> 1798<li> 1799<p><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a></p> 1800<ul> 1801<li><code>allowHalfOpen</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If set to <code>false</code>, then the socket will 1802automatically end the writable side when the readable side ends. 1803<strong>Default:</strong> <code>false</code>.</li> 1804<li><code>highWaterMark</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Optionally overrides all <a href="#class-netsocket"><code>net.Socket</code></a>s' 1805<code>readableHighWaterMark</code> and <code>writableHighWaterMark</code>. 1806<strong>Default:</strong> See <a href="stream.html#streamgetdefaulthighwatermarkobjectmode"><code>stream.getDefaultHighWaterMark()</code></a>.</li> 1807<li><code>pauseOnConnect</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> Indicates whether the socket should be 1808paused on incoming connections. <strong>Default:</strong> <code>false</code>.</li> 1809<li><code>noDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If set to <code>true</code>, it disables the use of Nagle's algorithm immediately 1810after a new incoming connection is received. <strong>Default:</strong> <code>false</code>.</li> 1811<li><code>keepAlive</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If set to <code>true</code>, it enables keep-alive functionality on the socket 1812immediately after a new incoming connection is received, similarly on what is done in 1813<a href="#socketsetkeepaliveenable-initialdelay"><code>socket.setKeepAlive([enable][, initialDelay])</code></a>. 1814<strong>Default:</strong> <code>false</code>.</li> 1815<li><code>keepAliveInitialDelay</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> If set to a positive number, it sets the initial delay before 1816the first keepalive probe is sent on an idle socket.<strong>Default:</strong> <code>0</code>.</li> 1817</ul> 1818</li> 1819<li> 1820<p><code>connectionListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Automatically set as a listener for the 1821<a href="#event-connection"><code>'connection'</code></a> event.</p> 1822</li> 1823<li> 1824<p>Returns: <a href="net.html#class-netserver" class="type"><net.Server></a></p> 1825</li> 1826</ul> 1827<p>Creates a new TCP or <a href="#ipc-support">IPC</a> server.</p> 1828<p>If <code>allowHalfOpen</code> is set to <code>true</code>, when the other end of the socket 1829signals the end of transmission, the server will only send back the end of 1830transmission when <a href="#socketenddata-encoding-callback"><code>socket.end()</code></a> is explicitly called. For example, in the 1831context of TCP, when a FIN packed is received, a FIN packed is sent 1832back only when <a href="#socketenddata-encoding-callback"><code>socket.end()</code></a> is explicitly called. Until then the 1833connection is half-closed (non-readable but still writable). See <a href="#event-end"><code>'end'</code></a> 1834event and <a href="https://tools.ietf.org/html/rfc1122">RFC 1122</a> (section 4.2.2.13) for more information.</p> 1835<p>If <code>pauseOnConnect</code> is set to <code>true</code>, then the socket associated with each 1836incoming connection will be paused, and no data will be read from its handle. 1837This allows connections to be passed between processes without any data being 1838read by the original process. To begin reading data from a paused socket, call 1839<a href="#socketresume"><code>socket.resume()</code></a>.</p> 1840<p>The server can be a TCP server or an <a href="#ipc-support">IPC</a> server, depending on what it 1841<a href="#serverlisten"><code>listen()</code></a> to.</p> 1842<p>Here is an example of a TCP echo server which listens for connections 1843on port 8124:</p> 1844<pre><code class="language-js"><span class="hljs-keyword">const</span> net = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:net'</span>); 1845<span class="hljs-keyword">const</span> server = net.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">c</span>) =></span> { 1846 <span class="hljs-comment">// 'connection' listener.</span> 1847 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'client connected'</span>); 1848 c.<span class="hljs-title function_">on</span>(<span class="hljs-string">'end'</span>, <span class="hljs-function">() =></span> { 1849 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'client disconnected'</span>); 1850 }); 1851 c.<span class="hljs-title function_">write</span>(<span class="hljs-string">'hello\r\n'</span>); 1852 c.<span class="hljs-title function_">pipe</span>(c); 1853}); 1854server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'error'</span>, <span class="hljs-function">(<span class="hljs-params">err</span>) =></span> { 1855 <span class="hljs-keyword">throw</span> err; 1856}); 1857server.<span class="hljs-title function_">listen</span>(<span class="hljs-number">8124</span>, <span class="hljs-function">() =></span> { 1858 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'server bound'</span>); 1859});</code> <button class="copy-button">copy</button></pre> 1860<p>Test this by using <code>telnet</code>:</p> 1861<pre><code class="language-console"><span class="hljs-meta prompt_">$ </span><span class="language-bash">telnet localhost 8124</span></code> <button class="copy-button">copy</button></pre> 1862<p>To listen on the socket <code>/tmp/echo.sock</code>:</p> 1863<pre><code class="language-js">server.<span class="hljs-title function_">listen</span>(<span class="hljs-string">'/tmp/echo.sock'</span>, <span class="hljs-function">() =></span> { 1864 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'server bound'</span>); 1865});</code> <button class="copy-button">copy</button></pre> 1866<p>Use <code>nc</code> to connect to a Unix domain socket server:</p> 1867<pre><code class="language-console"><span class="hljs-meta prompt_">$ </span><span class="language-bash">nc -U /tmp/echo.sock</span></code> <button class="copy-button">copy</button></pre> 1868</section><section><h3><code>net.getDefaultAutoSelectFamily()</code><span><a class="mark" href="#netgetdefaultautoselectfamily" id="netgetdefaultautoselectfamily">#</a></span><a aria-hidden="true" class="legacy" id="net_net_getdefaultautoselectfamily"></a></h3> 1869<div class="api_metadata"> 1870<span>Added in: v19.4.0</span> 1871</div> 1872<p>Gets the current default value of the <code>autoSelectFamily</code> option of <a href="#socketconnectoptions-connectlistener"><code>socket.connect(options)</code></a>.</p> 1873<ul> 1874<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> The current default value of the <code>autoSelectFamily</code> option.</li> 1875</ul> 1876</section><section><h3><code>net.setDefaultAutoSelectFamily(value)</code><span><a class="mark" href="#netsetdefaultautoselectfamilyvalue" id="netsetdefaultautoselectfamilyvalue">#</a></span><a aria-hidden="true" class="legacy" id="net_net_setdefaultautoselectfamily_value"></a></h3> 1877<div class="api_metadata"> 1878<span>Added in: v19.4.0</span> 1879</div> 1880<p>Sets the default value of the <code>autoSelectFamily</code> option of <a href="#socketconnectoptions-connectlistener"><code>socket.connect(options)</code></a>.</p> 1881<ul> 1882<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> The new default value. The initial default value is <code>false</code>.</li> 1883</ul> 1884</section><section><h3><code>net.getDefaultAutoSelectFamilyAttemptTimeout()</code><span><a class="mark" href="#netgetdefaultautoselectfamilyattempttimeout" id="netgetdefaultautoselectfamilyattempttimeout">#</a></span><a aria-hidden="true" class="legacy" id="net_net_getdefaultautoselectfamilyattempttimeout"></a></h3> 1885<div class="api_metadata"> 1886<span>Added in: v18.18.0</span> 1887</div> 1888<p>Gets the current default value of the <code>autoSelectFamilyAttemptTimeout</code> option of <a href="#socketconnectoptions-connectlistener"><code>socket.connect(options)</code></a>.</p> 1889<ul> 1890<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> The current default value of the <code>autoSelectFamilyAttemptTimeout</code> option.</li> 1891</ul> 1892</section><section><h3><code>net.setDefaultAutoSelectFamilyAttemptTimeout(value)</code><span><a class="mark" href="#netsetdefaultautoselectfamilyattempttimeoutvalue" id="netsetdefaultautoselectfamilyattempttimeoutvalue">#</a></span><a aria-hidden="true" class="legacy" id="net_net_setdefaultautoselectfamilyattempttimeout_value"></a></h3> 1893<div class="api_metadata"> 1894<span>Added in: v18.18.0</span> 1895</div> 1896<p>Sets the default value of the <code>autoSelectFamilyAttemptTimeout</code> option of <a href="#socketconnectoptions-connectlistener"><code>socket.connect(options)</code></a>.</p> 1897<ul> 1898<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> The new default value, which must be a positive number. If the number is less than <code>10</code>, 1899the value <code>10</code> is used insted The initial default value is <code>250</code>.</li> 1900</ul> 1901</section><section><h3><code>net.isIP(input)</code><span><a class="mark" href="#netisipinput" id="netisipinput">#</a></span><a aria-hidden="true" class="legacy" id="net_net_isip_input"></a></h3> 1902<div class="api_metadata"> 1903<span>Added in: v0.3.0</span> 1904</div> 1905<ul> 1906<li><code>input</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1907<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li> 1908</ul> 1909<p>Returns <code>6</code> if <code>input</code> is an IPv6 address. Returns <code>4</code> if <code>input</code> is an IPv4 1910address in <a href="https://en.wikipedia.org/wiki/Dot-decimal_notation">dot-decimal notation</a> with no leading zeroes. Otherwise, returns 1911<code>0</code>.</p> 1912<pre><code class="language-js">net.<span class="hljs-title function_">isIP</span>(<span class="hljs-string">'::1'</span>); <span class="hljs-comment">// returns 6</span> 1913net.<span class="hljs-title function_">isIP</span>(<span class="hljs-string">'127.0.0.1'</span>); <span class="hljs-comment">// returns 4</span> 1914net.<span class="hljs-title function_">isIP</span>(<span class="hljs-string">'127.000.000.001'</span>); <span class="hljs-comment">// returns 0</span> 1915net.<span class="hljs-title function_">isIP</span>(<span class="hljs-string">'127.0.0.1/24'</span>); <span class="hljs-comment">// returns 0</span> 1916net.<span class="hljs-title function_">isIP</span>(<span class="hljs-string">'fhqwhgads'</span>); <span class="hljs-comment">// returns 0</span></code> <button class="copy-button">copy</button></pre> 1917</section><section><h3><code>net.isIPv4(input)</code><span><a class="mark" href="#netisipv4input" id="netisipv4input">#</a></span><a aria-hidden="true" class="legacy" id="net_net_isipv4_input"></a></h3> 1918<div class="api_metadata"> 1919<span>Added in: v0.3.0</span> 1920</div> 1921<ul> 1922<li><code>input</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1923<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1924</ul> 1925<p>Returns <code>true</code> if <code>input</code> is an IPv4 address in <a href="https://en.wikipedia.org/wiki/Dot-decimal_notation">dot-decimal notation</a> with no 1926leading zeroes. Otherwise, returns <code>false</code>.</p> 1927<pre><code class="language-js">net.<span class="hljs-title function_">isIPv4</span>(<span class="hljs-string">'127.0.0.1'</span>); <span class="hljs-comment">// returns true</span> 1928net.<span class="hljs-title function_">isIPv4</span>(<span class="hljs-string">'127.000.000.001'</span>); <span class="hljs-comment">// returns false</span> 1929net.<span class="hljs-title function_">isIPv4</span>(<span class="hljs-string">'127.0.0.1/24'</span>); <span class="hljs-comment">// returns false</span> 1930net.<span class="hljs-title function_">isIPv4</span>(<span class="hljs-string">'fhqwhgads'</span>); <span class="hljs-comment">// returns false</span></code> <button class="copy-button">copy</button></pre> 1931</section><section><h3><code>net.isIPv6(input)</code><span><a class="mark" href="#netisipv6input" id="netisipv6input">#</a></span><a aria-hidden="true" class="legacy" id="net_net_isipv6_input"></a></h3> 1932<div class="api_metadata"> 1933<span>Added in: v0.3.0</span> 1934</div> 1935<ul> 1936<li><code>input</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1937<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1938</ul> 1939<p>Returns <code>true</code> if <code>input</code> is an IPv6 address. Otherwise, returns <code>false</code>.</p> 1940<pre><code class="language-js">net.<span class="hljs-title function_">isIPv6</span>(<span class="hljs-string">'::1'</span>); <span class="hljs-comment">// returns true</span> 1941net.<span class="hljs-title function_">isIPv6</span>(<span class="hljs-string">'fhqwhgads'</span>); <span class="hljs-comment">// returns false</span></code> <button class="copy-button">copy</button></pre></section> 1942 <!-- API END --> 1943 </div> 1944 </div> 1945 </div> 1946</body> 1947</html> 1948