1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>websocket::stream::async_accept (1 of 3 overloads)</title> 5<link rel="stylesheet" href="../../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../../index.html" title="Chapter 1. Boost.Beast"> 8<link rel="up" href="../async_accept.html" title="websocket::stream::async_accept"> 9<link rel="prev" href="../async_accept.html" title="websocket::stream::async_accept"> 10<link rel="next" href="overload2.html" title="websocket::stream::async_accept (2 of 3 overloads)"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="../async_accept.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../async_accept.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h6 class="title"> 27<a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1"></a><a class="link" href="overload1.html" title="websocket::stream::async_accept (1 of 3 overloads)">websocket::stream::async_accept 28 (1 of 3 overloads)</a> 29</h6></div></div></div> 30<p> 31 Perform the WebSocket handshake asynchronously in the server role. 32 </p> 33<h7><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.h0"></a> 34 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.synopsis"></a></span><a class="link" href="overload1.html#beast.ref.boost__beast__websocket__stream.async_accept.overload1.synopsis">Synopsis</a> 35 </h7><pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 36 <span class="keyword">class</span> <span class="identifier">AcceptHandler</span> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span><a class="link" href="../executor_type.html" title="websocket::stream::executor_type">executor_type</a><span class="special">>></span> 37<a href="../../../../../../../../doc/html/boost_asio/reference/asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type" target="_top"><span class="emphasis"><em>DEDUCED</em></span></a> 38<span class="identifier">async_accept</span><span class="special">(</span> 39 <span class="identifier">AcceptHandler</span><span class="special">&&</span> <span class="identifier">handler</span> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span> <a class="link" href="../executor_type.html" title="websocket::stream::executor_type">executor_type</a> <span class="special">>{});</span> 40</pre> 41<h7><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.h1"></a> 42 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.description"></a></span><a class="link" href="overload1.html#beast.ref.boost__beast__websocket__stream.async_accept.overload1.description">Description</a> 43 </h7><p> 44 This initiating function is used to asynchronously begin performing the 45 <a href="https://en.wikipedia.org/wiki/WebSocket#Protocol_handshake" target="_top">WebSocket 46 handshake</a>, required before messages can be sent and received. 47 During the handshake, the client sends the Websocket Upgrade HTTP request, 48 and the server replies with an HTTP response indicating the result of 49 the handshake. This call always returns immediately. The asynchronous 50 operation will continue until one of the following conditions is true: 51 </p> 52<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 53<li class="listitem"> 54 The request is received and the response is sent. 55 </li> 56<li class="listitem"> 57 An error occurs. 58 </li> 59</ul></div> 60<p> 61 The algorithm, known as a <span class="emphasis"><em>composed asynchronous operation</em></span>, 62 is implemented in terms of calls to the next layer's <code class="computeroutput"><span class="identifier">async_read_some</span></code> 63 and <code class="computeroutput"><span class="identifier">async_write_some</span></code> 64 functions. No other operation may be performed on the stream until this 65 operation completes. If a valid upgrade request is received, an HTTP 66 response with a <a href="https://tools.ietf.org/html/rfc7230#section-3.1.2" target="_top">status-code</a> 67 of <a class="link" href="../../boost__beast__http__status.html" title="http::status"><code class="computeroutput"><span class="identifier">beast</span><span class="special">::</span><span class="identifier">http</span><span class="special">::</span><span class="identifier">status</span><span class="special">::</span><span class="identifier">switching_protocols</span></code></a> is sent 68 to the peer, otherwise a non-successful error is associated with the 69 operation. If the request size exceeds the capacity of the stream's internal 70 buffer, the error <a class="link" href="../../boost__beast__websocket__error.html" title="websocket::error"><code class="computeroutput"><span class="identifier">error</span><span class="special">::</span><span class="identifier">buffer_overflow</span></code></a> will be indicated. 71 To handle larger requests, an application should read the HTTP request 72 directly using <a class="link" href="../../boost__beast__http__async_read/overload1.html" title="http::async_read (1 of 2 overloads)"><code class="computeroutput"> 73 <span class="identifier">http</span><span class="special">::</span><span class="identifier">async_read</span> </code></a> and then pass the 74 request to the appropriate overload of <a class="link" href="../accept/overload1.html" title="websocket::stream::accept (1 of 6 overloads)"><code class="computeroutput"><span class="identifier">accept</span></code></a> or <a class="link" href="overload1.html" title="websocket::stream::async_accept (1 of 3 overloads)"><code class="computeroutput"><span class="identifier">async_accept</span></code></a> 75 </p> 76<h7><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.h2"></a> 77 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.parameters"></a></span><a class="link" href="overload1.html#beast.ref.boost__beast__websocket__stream.async_accept.overload1.parameters">Parameters</a> 78 </h7><div class="informaltable"><table class="table"> 79<colgroup> 80<col> 81<col> 82</colgroup> 83<thead><tr> 84<th> 85 <p> 86 Name 87 </p> 88 </th> 89<th> 90 <p> 91 Description 92 </p> 93 </th> 94</tr></thead> 95<tbody><tr> 96<td> 97 <p> 98 <code class="computeroutput"><span class="identifier">handler</span></code> 99 </p> 100 </td> 101<td> 102 <p> 103 The completion handler to invoke when the operation completes. 104 The implementation takes ownership of the handler by performing 105 a decay-copy. The equivalent function signature of the handler 106 must be: 107 </p> 108<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span> 109 <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">ec</span> <span class="comment">// Result of operation</span> 110<span class="special">);</span> 111</pre> 112 <p> 113 Regardless of whether the asynchronous operation completes 114 immediately or not, the handler will not be invoked from within 115 this function. Invocation of the handler will be performed 116 in a manner equivalent to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>. 117 </p> 118 </td> 119</tr></tbody> 120</table></div> 121<h7><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.h3"></a> 122 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload1.see_also"></a></span><a class="link" href="overload1.html#beast.ref.boost__beast__websocket__stream.async_accept.overload1.see_also">See 123 Also</a> 124 </h7><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> 125 <a href="https://tools.ietf.org/html/rfc6455#section-4.2" target="_top">Websocket 126 Opening Handshake Server Requirements (RFC6455)</a> 127 </li></ul></div> 128</div> 129<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 130<td align="left"></td> 131<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 132 Falco<p> 133 Distributed under the Boost Software License, Version 1.0. (See accompanying 134 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 135 </p> 136</div></td> 137</tr></table> 138<hr> 139<div class="spirit-nav"> 140<a accesskey="p" href="../async_accept.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../async_accept.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 141</div> 142</body> 143</html> 144
