template< class DynamicBuffer, class ReadHandler> async_read( DynamicBuffer& buffer, ReadHandler&& handler);
This function is used to asynchronously read a complete message. 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
The program must ensure that no other calls to
websocket::stream::async_read_some are performed
until this operation completes. Received message data is appended to the
buffer. The functions
websocket::stream::got_text may be used to query
the stream and determine the type of the last received message. Until the
operation completes, the implementation will read incoming control frames
and handle them automatically as follows:
websocket::stream::control_callback will be invoked
for each control frame.
websocket::closed will be indicated.
Pong frames and close frames sent by the implementation while the read operation is outstanding do not prevent the application from also writing message data, sending pings, sending pongs, or sending close frames.
A dynamic buffer to append message data to.
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 std::size_t bytes_written // Number of bytes appended to buffer );
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