A [*BodyReader] provides an online algorithm to transfer a series of zero or more buffers containing parsed body octets into a message container. The __parser__ creates an instance of this type when needed, and calls into it zero or more times to transfer buffers. The interface of [*BodyReader] is intended to allow the conversion of buffers into these scenarios for representation:

* Storing a body in a dynamic buffer
* Storing a body in a user defined container with a custom allocator
* Transformation of incoming body data before storage, for example

* Saving body data to a file

Associated Types

* [link beast.ref.boost__beast__http__is_body_reader `is_body_reader`]
* __Body__

Requirements

These requirements may undergo non-backward compatible

In this table:

* `R` denotes a type meeting the requirements of [*BodyReader].
* `B` denotes a __Body__ where

* `a` denotes a value of type `R`.
* `b` is an object whose type meets the requirements of __ConstBufferSequence__
* `h` denotes a value of type `header<isRequest, Fields>&`.
* `v` denotes a value of type `Body::value_type&`.
* `n` is a value of type `boost::optional<std::uint64_t>`.
* `ec` is a value of type [link beast.ref.boost__beast__error_code `error_code&`].

Valid expressions

Semantics, Pre/Post-conditions

Constructible from `h` and `v`. The lifetime of `h` and `v` is guaranteed to end no earlier than after the `R` is destroyed. The reader shall not access the contents of `h` or `v` before the first call to `init`, permitting lazy construction of the message.

Called once to fully initialize the object before any calls to `put`. The message body is valid before entering this function, and remains valid until the reader is destroyed. The value of `n` will be set to the content length of the body if known, otherwise `n` will be equal to `boost::none`. Implementations of [*BodyReader] may use this information to optimize allocation.

The function will ensure that `!ec` is `true` if there was no error or set to the appropriate error code if there was one.

`std::size_t`

This function is called to append some or all of the buffers specified by `b` into the body representation. The number of bytes inserted from `b` is returned. If the number of bytes inserted is less than the total input, the remainder of the input will be presented in the next call to `put`. The function will ensure that `!ec` is `true` if there was no error or set to the appropriate error code if there was one.

This function is called when no more body octets are remaining. The function will ensure that `!ec` is `true` if there was no error or set to the appropriate error code if there was one.

`is_body_reader<B>`

`std::true_type`

An alias for `std::true_type` for `B`, otherwise an alias for `std::false_type`.