http::basic_parser

A parser for decoding HTTP/1 wire format messages.

Synopsis

Defined in header <boost/beast/http/basic_parser.hpp>

template<
    bool isRequest>
class basic_parser

Types

Name	Description
is_request	`true` if this parser parses requests, `false` for responses.

Member Functions

Name	Description
basic_parser [constructor]	Copy constructor.
body_limit	Set the limit on the payload body.
chunked	Returns `true` if the last value for Transfer-Encoding is "chunked".
content_length	Returns the optional value of Content-Length if known.
content_length_remaining	Returns the remaining content length if known.
eager	Returns `true` if the eager parse option is set. — Set the eager parse option.
got_some	Returns `true` if the parser has received at least one byte of input.
header_limit	Set a limit on the total size of the header.
is_done	Returns `true` if the message is complete.
is_header_done	Returns `true` if a the parser has produced the full header.
keep_alive	Returns `true` if the message has keep-alive connection semantics.
need_eof	Returns `true` if the message semantics require an end of file.
operator=	Copy assignment.
put	Write a buffer sequence to the parser.
put_eof	Inform the parser that the end of stream was reached.
skip	Returns `true` if the skip parse option is set. — Set the skip parse option.
upgrade	Returns `true` if the message is an upgrade message.
~basic_parser [destructor]	Destructor.

Protected Member Functions

Name	Description
basic_parser [constructor]	Default constructor. — Move constructor.
on_body_impl	Called each time additional data is received representing the content body.
on_body_init_impl	Called once before the body is processed.
on_chunk_body_impl	Called each time additional data is received representing part of a body chunk.
on_chunk_header_impl	Called each time a new chunk header of a chunk encoded body is received.
on_field_impl	Called once for each complete field in the HTTP header.
on_finish_impl	Called once when the complete message is received.
on_header_impl	Called once after the complete HTTP header is received.
on_request_impl	Called after receiving the request-line.
on_response_impl	Called after receiving the status-line.
operator=	Move assignment.

This parser is designed to efficiently parse messages in the HTTP/1 wire format. It allocates no memory when input is presented as a single contiguous buffer, and uses minimal state. It will handle chunked encoding and it understands the semantics of the Connection, Content-Length, and Upgrade fields. The parser is optimized for the case where the input buffer sequence consists of a single contiguous buffer. The beast::basic_flat_buffer class is provided, which guarantees that the input sequence of the stream buffer will be represented by exactly one contiguous buffer. To ensure the optimum performance of the parser, use beast::basic_flat_buffer with HTTP algorithms such as read, read_some, async_read, and async_read_some. Alternatively, the caller may use custom techniques to ensure that the structured portion of the HTTP message (header or chunk header) is contained in a linear buffer.

The interface to the parser uses virtual member functions. To use this class, derive your type from basic_parser. When bytes are presented, the implementation will make a series of zero or more calls to virtual functions, which the derived class must implement.

Every virtual function must be provided by the derived class, or else a compilation error will be generated. The implementation will make sure that ec is clear before each virtual function is invoked. If a virtual function sets an error, it is propagated out of the parser to the caller.

Template Parameters

Type	Description
`isRequest`	A `bool` indicating whether the parser will be presented with request or response message.

Remarks

If the parser encounters a field value with obs-fold longer than 4 kilobytes in length, an error is generated.