Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a snapshot of the develop branch, built from commit 721fc48582.
websocket::stream::async_accept (2 of 3 overloads)

Perform the WebSocket handshake asynchronously in the server role.

    class ConstBufferSequence,
    class AcceptHandler = net::default_completion_token_t<executor_type>>
    ConstBufferSequence const& buffers,
    AcceptHandler&& handler = net::default_completion_token_t< executor_type >{});

This initiating function is used to asynchronously begin performing the WebSocket handshake, required before messages can be sent and received. During the handshake, the client sends the Websocket Upgrade HTTP request, and the server replies with an HTTP response indicating the result of the handshake. This call always returns immediately. The asynchronous operation will continue until one of the following conditions is true:

The algorithm, known as a composed asynchronous operation, is implemented in terms of calls to the next layer's async_read_some and async_write_some functions. No other operation may be performed on the stream until this operation completes. If a valid upgrade request is received, an HTTP response with a status-code of beast::http::status::switching_protocols is sent to the peer, otherwise a non-successful error is associated with the operation. If the request size exceeds the capacity of the stream's internal buffer, the error error::buffer_overflow will be indicated. To handle larger requests, an application should read the HTTP request directly using http::async_read and then pass the request to the appropriate overload of accept or async_accept





Caller provided data that has already been received on the stream. This may be used for implementations allowing multiple protocols on the same stream. The buffered data will first be applied to the handshake, and then to received WebSocket frames. The implementation will copy the caller provided data before the function returns.


The completion handler to invoke when the operation completes. The implementation takes ownership of the handler by performing a decay-copy. The equivalent function signature of the handler must be:

void handler(
    error_code const& ec    // Result of operation

Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using net::post.

See Also