Parser Stream Operations

Non-trivial algorithms need to do more than receive entire messages at once, such as:

* Receive the header first and body later.

* Receive a large body using a fixed-size buffer.

* Receive a message incrementally: bounded work in each I/O cycle.

* Defer the commitment to a __Body__ type until after reading the header.

These types of operations require callers to manage the lifetime of associated state, by constructing a class derived from __basic_parser__. Beast comes with the derived instance __parser__ which creates complete __message__ objects using the __basic_fields__ Fields container.

/// An HTTP/1 parser for producing a message.
template<
bool isRequest, // `true` to parse an HTTP request
class Body, // The Body type for the resulting message
class Allocator = std::allocator<char>> // The type of allocator for the header
class parser
: public basic_parser<...>;

[link beast.ref.boost__beast__http__request_parser `request_parser`]

/// An HTTP/1 parser for producing a request message.
template<class Body, class Allocator = std::allocator<char>>
using request_parser = parser<true, Body, Allocator>;

[link beast.ref.boost__beast__http__response_parser `response_parser`]

/// An HTTP/1 parser for producing a response message.
template<class Body, class Allocator = std::allocator<char>>
using response_parser = parser<false, Body, Allocator>;

The __basic_parser__ and classes derived from it handle octet streams

The stream operations which work on parsers are:

Parser Stream Operations

[link beast.ref.boost__beast__http__read.overload1 [*read]]

Read everything into a parser from a __SyncReadStream__.

[link beast.ref.boost__beast__http__async_read.overload1 [*async_read]]

Read everything into a parser asynchronously from an __AsyncReadStream__.

[link beast.ref.boost__beast__http__read_header.overload1 [*read_header]]