1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>websocket::stream::async_accept (3 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="overload2.html" title="websocket::stream::async_accept (2 of 3 overloads)"> 10<link rel="next" href="../close.html" title="websocket::stream::close"> 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="overload2.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="../close.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.overload3"></a><a class="link" href="overload3.html" title="websocket::stream::async_accept (3 of 3 overloads)">websocket::stream::async_accept 28 (3 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.overload3.h0"></a> 34 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload3.synopsis"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__websocket__stream.async_accept.overload3.synopsis">Synopsis</a> 35 </h7><pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 36 <span class="keyword">class</span> <a class="link" href="../../../concepts/Body.html" title="Body"><span class="emphasis"><em>Body</em></span></a><span class="special">,</span> 37 <span class="keyword">class</span> <a href="https://en.cppreference.com/w/cpp/named_req/Allocator" target="_top"><span class="emphasis"><em>Allocator</em></span></a><span class="special">,</span> 38 <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> 39<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> 40<span class="identifier">async_accept</span><span class="special">(</span> 41 <span class="identifier">http</span><span class="special">::</span><span class="identifier">request</span><span class="special"><</span> <span class="identifier">Body</span><span class="special">,</span> <span class="identifier">http</span><span class="special">::</span><span class="identifier">basic_fields</span><span class="special"><</span> <span class="identifier">Allocator</span> <span class="special">>></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">req</span><span class="special">,</span> 42 <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> 43</pre> 44<h7><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload3.h1"></a> 45 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload3.description"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__websocket__stream.async_accept.overload3.description">Description</a> 46 </h7><p> 47 This initiating function is used to asynchronously begin performing the 48 <a href="https://en.wikipedia.org/wiki/WebSocket#Protocol_handshake" target="_top">WebSocket 49 handshake</a>, required before messages can be sent and received. 50 During the handshake, the client sends the Websocket Upgrade HTTP request, 51 and the server replies with an HTTP response indicating the result of 52 the handshake. This call always returns immediately. The asynchronous 53 operation will continue until one of the following conditions is true: 54 </p> 55<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 56<li class="listitem"> 57 The request is received and the response is sent. 58 </li> 59<li class="listitem"> 60 An error occurs. 61 </li> 62</ul></div> 63<p> 64 The algorithm, known as a <span class="emphasis"><em>composed asynchronous operation</em></span>, 65 is implemented in terms of calls to the next layer's <code class="computeroutput"><span class="identifier">async_read_some</span></code> 66 and <code class="computeroutput"><span class="identifier">async_write_some</span></code> 67 functions. No other operation may be performed on the stream until this 68 operation completes. If a valid upgrade request is received, an HTTP 69 response with a <a href="https://tools.ietf.org/html/rfc7230#section-3.1.2" target="_top">status-code</a> 70 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 71 to the peer, otherwise a non-successful error is associated with the 72 operation. 73 </p> 74<h7><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload3.h2"></a> 75 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload3.parameters"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__websocket__stream.async_accept.overload3.parameters">Parameters</a> 76 </h7><div class="informaltable"><table class="table"> 77<colgroup> 78<col> 79<col> 80</colgroup> 81<thead><tr> 82<th> 83 <p> 84 Name 85 </p> 86 </th> 87<th> 88 <p> 89 Description 90 </p> 91 </th> 92</tr></thead> 93<tbody> 94<tr> 95<td> 96 <p> 97 <code class="computeroutput"><span class="identifier">req</span></code> 98 </p> 99 </td> 100<td> 101 <p> 102 An object containing the HTTP Upgrade request. Ownership is 103 not transferred, the implementation will not access this object 104 from other threads. 105 </p> 106 </td> 107</tr> 108<tr> 109<td> 110 <p> 111 <code class="computeroutput"><span class="identifier">handler</span></code> 112 </p> 113 </td> 114<td> 115 <p> 116 The completion handler to invoke when the operation completes. 117 The implementation takes ownership of the handler by performing 118 a decay-copy. The equivalent function signature of the handler 119 must be: 120 </p> 121<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> 122 <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> 123<span class="special">);</span> 124</pre> 125 <p> 126 Regardless of whether the asynchronous operation completes 127 immediately or not, the handler will not be invoked from within 128 this function. Invocation of the handler will be performed 129 in a manner equivalent to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>. 130 </p> 131 </td> 132</tr> 133</tbody> 134</table></div> 135<h7><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload3.h3"></a> 136 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_accept.overload3.see_also"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__websocket__stream.async_accept.overload3.see_also">See 137 Also</a> 138 </h7><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> 139 <a href="https://tools.ietf.org/html/rfc6455#section-4.2" target="_top">Websocket 140 Opening Handshake Server Requirements (RFC6455)</a> 141 </li></ul></div> 142</div> 143<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 144<td align="left"></td> 145<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 146 Falco<p> 147 Distributed under the Boost Software License, Version 1.0. (See accompanying 148 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>) 149 </p> 150</div></td> 151</tr></table> 152<hr> 153<div class="spirit-nav"> 154<a accesskey="p" href="overload2.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="../close.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 155</div> 156</body> 157</html> 158
