Read a complete message from a stream asynchronously using a parser.
Defined in header
template< class AsyncReadStream, class DynamicBuffer, bool isRequest, class Derived, class ReadHandler> DEDUCED async_read( AsyncReadStream& stream, DynamicBuffer& buffer, basic_parser< isRequest, Derived >& parser, ReadHandler&& handler);
This function is used to asynchronously read a complete message from a
stream into a subclass of
http::basic_parser. The function call
always returns immediately. The asynchronous operation will continue until
one of the following conditions is true:
This operation is implemented in terms of one or more calls to the stream's
and is known as a composed operation. The program
must ensure that the stream performs no other reads until this operation
completes. The implementation may read additional octets that lie past
the end of the message being read. This additional data is stored in the
dynamic buffer, which must be retained for subsequent reads.
If the stream returns the error
indicating the end of file during a read, the error returned from this
function will be:
The stream from which the data is to be read. The type must support the AsyncReadStream concept.
A DynamicBuffer holding additional bytes read by the implementation from the stream. This is both an input and an output parameter; on entry, any data in the dynamic buffer's input sequence will be given to the parser first.
The parser to use. The object must remain valid at least until the handler is called; ownership is not transferred.
Invoked when the operation completes. The handler may be moved or copied as needed. The equivalent function signature of the handler must be:
void handler( error_code const& error, // result of operation, std::size_t bytes_transferred // the number of bytes transferred to the parser );
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
The implementation will call
http::basic_parser::eager with the value
true on the parser passed in.