forked from boostorg/beast
68 lines
2.4 KiB
Plaintext
68 lines
2.4 KiB
Plaintext
[/
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Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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Official repository: https://github.com/boostorg/beast
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]
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[section Handshaking (Clients)]
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A WebSocket session begins when a client sends the HTTP/1.1
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[@https://tools.ietf.org/html/rfc7230#section-6.7 Upgrade]
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request for
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[@https://tools.ietf.org/html/rfc6455#section-1.3 websocket],
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and the server sends an appropriate response indicating that
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the request was accepted and that the connection has been upgraded.
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The Upgrade request must include the
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[@https://tools.ietf.org/html/rfc7230#section-5.4 Host]
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field, and the
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[@https://tools.ietf.org/html/rfc7230#section-5.3 target]
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of the resource to request.
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A typical HTTP Upgrade request created and sent by the implementation
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will look like this:
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[table WebSocket HTTP Upgrade Request
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[[Serialized Octets][Description]]
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[[
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```
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GET / HTTP/1.1
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Host: www.example.com
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Upgrade: websocket
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Connection: upgrade
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Sec-WebSocket-Key: 2pGeTR0DsE4dfZs2pH+8MA==
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Sec-WebSocket-Version: 13
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User-Agent: Boost.Beast/216
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```
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][
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The host and target parameters become part of the Host field
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and request-target in the resulting HTTP request. The key is
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generated by the implementation. Callers may add fields or
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modify fields by providing a ['decorator], described later.
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]]]
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The
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[link beast.ref.boost__beast__websocket__stream `stream`]
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member functions
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[link beast.ref.boost__beast__websocket__stream.handshake `handshake`] and
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[link beast.ref.boost__beast__websocket__stream.async_handshake `async_handshake`]
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are used to send the request with the required host and target strings. The
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code below sends the WebSocket HTTP Upgrade request, then reads and processes
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the response:
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[code_websocket_3_client_1]
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When a client receives an HTTP Upgrade response from the server indicating
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a successful upgrade, the caller may wish to perform additional validation
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on the received HTTP response message. For example, to check that the
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response to a basic authentication challenge is valid. To achieve this,
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overloads of the handshake member function allow the caller to store the
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received HTTP message in an output reference argument of type
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[link beast.ref.boost__beast__websocket__response_type `response_type`]
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as follows:
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[code_websocket_3_client_2]
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[endsect]
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