Struct AsyncBody

pub struct AsyncBody(/* private fields */);

Contains the body of an asynchronous HTTP request or response.

This type is used to encapsulate the underlying stream or region of memory where the contents of the body are stored. An AsyncBody can be created from many types of sources using the Into trait or one of its constructor functions.

For asynchronous requests, you must use an asynchronous body, because the entire request lifecycle is also asynchronous. You can create a body from anything that implements AsyncRead, which AsyncBody itself also implements.

For synchronous requests, use Body instead.

Implementations

impl AsyncBody

pub const fn empty() -> Self

Create a new empty body.

An empty body represents the absence of a body, which is semantically different than the presence of a body of zero length.

pub fn from_bytes_static<B>(bytes: B) -> Self

where B: AsRef<[u8]> + 'static,

Create a new body from a potentially static byte buffer.

The body will have a known length equal to the number of bytes given.

This will try to prevent a copy if the type passed in can be re-used, otherwise the buffer will be copied first. This method guarantees to not require a copy for the following types:

• &'static [u8]
• &'static str

Examples

use isahc::Body;

// Create a body from a static string.
let body = Body::from_bytes_static("hello world");

pub fn from_reader<R>(read: R) -> Self

where R: AsyncRead + Send + Sync + 'static,

Create a streaming body that reads from the given reader.

The body will have an unknown length. When used as a request body, chunked transfer encoding might be used to send the request.

pub fn from_reader_sized<R>(read: R, length: u64) -> Self

where R: AsyncRead + Send + Sync + 'static,

Create a streaming body with a known length.

If the size of the body is known in advance, such as with a file, then this function can be used to create a body that can determine its Content-Length while still reading the bytes asynchronously.

Giving a value for length that doesn’t actually match how much data the reader will produce may result in errors when sending the body in a request.

pub fn is_empty(&self) -> bool

Report if this body is empty.

This is not necessarily the same as checking for self.len() == Some(0). Since HTTP message bodies are optional, there is a semantic difference between the absence of a body and the presence of a zero-length body. This method will only return true for the former.

pub fn len(&self) -> Option<u64>

Get the size of the body, if known.

The value reported by this method is used to set the Content-Length for outgoing requests.

When coming from a response, this method will report the value of the Content-Length response header if present. If this method returns None then there’s a good chance that the server used something like chunked transfer encoding to send the response body.

Since the length may be determined totally separately from the actual bytes, even if a value is returned it should not be relied on as always being accurate, and should be treated as a “hint”.

pub fn reset(&mut self) -> bool

If this body is repeatable, reset the body stream back to the start of the content. Returns false if the body cannot be reset.

Trait Implementations

impl AsyncRead for AsyncBody

fn poll_read( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut [u8], ) -> Poll<Result<usize>>

Attempt to read from the AsyncRead into buf.

fn poll_read_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &mut [IoSliceMut<'_>], ) -> Poll<Result<usize, Error>>

Attempt to read from the AsyncRead into bufs using vectored IO operations.

impl Debug for AsyncBody

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for AsyncBody

fn default() -> Self

Returns the “default value” for a type.

impl From<&[u8]> for AsyncBody

fn from(body: &[u8]) -> Self

Converts to this type from the input type.

impl From<&str> for AsyncBody

fn from(body: &str) -> Self

Converts to this type from the input type.

impl From<()> for AsyncBody

fn from(_: ()) -> Self

Converts to this type from the input type.

impl<T: Into<Self>> From<Option<T>> for AsyncBody

fn from(body: Option<T>) -> Self

Converts to this type from the input type.

impl From<String> for AsyncBody

fn from(body: String) -> Self

Converts to this type from the input type.

impl From<Vec<u8>> for AsyncBody

fn from(body: Vec<u8>) -> Self

Converts to this type from the input type.