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boost_beast/doc/qbk/06_websocket/1_streams.qbk
Vinnie Falco b5389ba5f2 Documentation tidying
fix #836
2017-10-27 11:16:09 -07:00

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[/
Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Official repository: https://github.com/boostorg/beast
]
[section Creating Streams]
The interface to the WebSocket implementation is a single template class
[link beast.ref.boost__beast__websocket__stream `stream`]
which wraps an existing network transport object or other type of
octet oriented stream. The wrapped object is called the "next layer"
and must meet the requirements of __SyncStream__ if synchronous
operations are performed, __AsyncStream__ if asynchronous operations
are performed, or both. Any arguments supplied during construction of
the stream wrapper are passed to next layer's constructor.
Here we declare a websocket stream over a TCP/IP socket with ownership
of the socket. The `io_context` argument is forwarded to the wrapped
socket's constructor:
[ws_snippet_2]
[heading Using SSL]
To use WebSockets over SSL, use an instance of the __ssl_stream__
class template as the template type for the stream. The required
__io_context__ and __ssl_context__ arguments are forwarded to the
wrapped stream's constructor:
[wss_snippet_1]
[wss_snippet_2]
[important
Code which declares websocket stream objects using Asio SSL types
must include the file [include_file boost/beast/websocket/ssl.hpp].
]
[heading Non-owning References]
If a socket type supports move construction, a websocket stream may be
constructed around the already existing socket by invoking the move
constructor signature:
[ws_snippet_3]
Or, the wrapper can be constructed with a non-owning reference. In
this case, the caller is responsible for managing the lifetime of the
underlying socket being wrapped:
[ws_snippet_4]
Once the WebSocket stream wrapper is created, the wrapped object may be
accessed by calling
[link beast.ref.boost__beast__websocket__stream.next_layer.overload1 `stream::next_layer`]:
[ws_snippet_5]
[warning
Initiating operations on the next layer while websocket
operations are being performed may result in undefined behavior.
]
[endsect]