aws_smithy_types/body.rs
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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
//! Types for representing the body of an HTTP request or response
use bytes::Bytes;
use pin_project_lite::pin_project;
use std::error::Error as StdError;
use std::fmt::{self, Debug, Formatter};
use std::future::poll_fn;
use std::pin::Pin;
use std::sync::Arc;
use std::task::{Context, Poll};
/// This module is named after the `http-body` version number since we anticipate
/// needing to provide equivalent functionality for 1.x of that crate in the future.
/// The name has a suffix `_x` to avoid name collision with a third-party `http-body-0-4`.
#[cfg(feature = "http-body-0-4-x")]
pub mod http_body_0_4_x;
#[cfg(feature = "http-body-1-x")]
pub mod http_body_1_x;
/// A generic, boxed error that's `Send` and `Sync`
pub type Error = Box<dyn StdError + Send + Sync>;
pin_project! {
/// SdkBody type
///
/// This is the Body used for dispatching all HTTP Requests.
/// For handling responses, the type of the body will be controlled
/// by the HTTP stack.
///
pub struct SdkBody {
#[pin]
inner: Inner,
// An optional function to recreate the inner body
//
// In the event of retry, this function will be called to generate a new body. See
// [`try_clone()`](SdkBody::try_clone)
rebuild: Option<Arc<dyn (Fn() -> Inner) + Send + Sync>>,
bytes_contents: Option<Bytes>
}
}
impl Debug for SdkBody {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
f.debug_struct("SdkBody")
.field("inner", &self.inner)
.field("retryable", &self.rebuild.is_some())
.finish()
}
}
/// A boxed generic HTTP body that, when consumed, will result in [`Bytes`] or an [`Error`].
enum BoxBody {
// This is enabled by the **dependency**, not the feature. This allows us to construct it
// whenever we have the dependency and keep the APIs private
#[cfg(any(
feature = "http-body-0-4-x",
feature = "http-body-1-x",
feature = "rt-tokio"
))]
// will be dead code with `--no-default-features --features rt-tokio`
HttpBody04(#[allow(dead_code)] http_body_0_4::combinators::BoxBody<Bytes, Error>),
}
pin_project! {
#[project = InnerProj]
enum Inner {
// An in-memory body
Once {
inner: Option<Bytes>
},
// A streaming body
Dyn {
#[pin]
inner: BoxBody,
},
/// When a streaming body is transferred out to a stream parser, the body is replaced with
/// `Taken`. This will return an Error when polled. Attempting to read data out of a `Taken`
/// Body is a bug.
Taken,
}
}
impl Debug for Inner {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
match &self {
Inner::Once { inner: once } => f.debug_tuple("Once").field(once).finish(),
Inner::Dyn { .. } => write!(f, "BoxBody"),
Inner::Taken => f.debug_tuple("Taken").finish(),
}
}
}
impl SdkBody {
/// Construct an explicitly retryable SDK body
///
/// _Note: This is probably not what you want_
///
/// All bodies constructed from in-memory data (`String`, `Vec<u8>`, `Bytes`, etc.) will be
/// retryable out of the box. If you want to read data from a file, you should use
/// [`ByteStream::from_path`](crate::byte_stream::ByteStream::from_path). This function
/// is only necessary when you need to enable retries for your own streaming container.
pub fn retryable(f: impl Fn() -> SdkBody + Send + Sync + 'static) -> Self {
let initial = f();
SdkBody {
inner: initial.inner,
rebuild: Some(Arc::new(move || f().inner)),
bytes_contents: initial.bytes_contents,
}
}
/// When an SdkBody is read, the inner data must be consumed. In order to do this, the SdkBody
/// is swapped with a "taken" body. This "taken" body cannot be read but aids in debugging.
pub fn taken() -> Self {
Self {
inner: Inner::Taken,
rebuild: None,
bytes_contents: None,
}
}
/// Create an empty SdkBody for requests and responses that don't transfer any data in the body.
pub fn empty() -> Self {
Self {
inner: Inner::Once { inner: None },
rebuild: Some(Arc::new(|| Inner::Once { inner: None })),
bytes_contents: Some(Bytes::new()),
}
}
pub(crate) async fn next(&mut self) -> Option<Result<Bytes, Error>> {
let mut me = Pin::new(self);
poll_fn(|cx| me.as_mut().poll_next(cx)).await
}
pub(crate) fn poll_next(
self: Pin<&mut Self>,
#[allow(unused)] cx: &mut Context<'_>,
) -> Poll<Option<Result<Bytes, Error>>> {
let this = self.project();
match this.inner.project() {
InnerProj::Once { ref mut inner } => {
let data = inner.take();
match data {
Some(bytes) if bytes.is_empty() => Poll::Ready(None),
Some(bytes) => Poll::Ready(Some(Ok(bytes))),
None => Poll::Ready(None),
}
}
InnerProj::Dyn { inner: body } => match body.get_mut() {
#[cfg(feature = "http-body-0-4-x")]
BoxBody::HttpBody04(box_body) => {
use http_body_0_4::Body;
Pin::new(box_body).poll_data(cx)
}
#[allow(unreachable_patterns)]
_ => unreachable!(
"enabling `http-body-0-4-x` is the only way to create the `Dyn` variant"
),
},
InnerProj::Taken => {
Poll::Ready(Some(Err("A `Taken` body should never be polled".into())))
}
}
}
#[cfg(any(
feature = "http-body-0-4-x",
feature = "http-body-1-x",
feature = "rt-tokio"
))]
pub(crate) fn from_body_0_4_internal<T, E>(body: T) -> Self
where
T: http_body_0_4::Body<Data = Bytes, Error = E> + Send + Sync + 'static,
E: Into<Error> + 'static,
{
Self {
inner: Inner::Dyn {
inner: BoxBody::HttpBody04(http_body_0_4::combinators::BoxBody::new(
body.map_err(Into::into),
)),
},
rebuild: None,
bytes_contents: None,
}
}
#[cfg(any(feature = "http-body-0-4-x", feature = "http-body-1-x",))]
pub(crate) fn poll_next_trailers(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<http::HeaderMap<http::HeaderValue>>, Error>> {
let this = self.project();
match this.inner.project() {
InnerProj::Once { .. } => Poll::Ready(Ok(None)),
InnerProj::Dyn { inner } => match inner.get_mut() {
BoxBody::HttpBody04(box_body) => {
use http_body_0_4::Body;
Pin::new(box_body).poll_trailers(cx)
}
},
InnerProj::Taken => Poll::Ready(Err(
"A `Taken` body should never be polled for trailers".into(),
)),
}
}
/// If possible, return a reference to this body as `&[u8]`
///
/// If this SdkBody is NOT streaming, this will return the byte slab
/// If this SdkBody is streaming, this will return `None`
pub fn bytes(&self) -> Option<&[u8]> {
match &self.bytes_contents {
Some(b) => Some(b),
None => None,
}
}
/// Attempt to clone this SdkBody. This will fail if the inner data is not cloneable, such as when
/// it is a single-use stream that can't be recreated.
pub fn try_clone(&self) -> Option<Self> {
self.rebuild.as_ref().map(|rebuild| {
let next = rebuild();
Self {
inner: next,
rebuild: self.rebuild.clone(),
bytes_contents: self.bytes_contents.clone(),
}
})
}
/// Return `true` if this SdkBody is streaming, `false` if it is in-memory.
pub fn is_streaming(&self) -> bool {
matches!(self.inner, Inner::Dyn { .. })
}
/// Return the length, in bytes, of this SdkBody. If this returns `None`, then the body does not
/// have a known length.
pub fn content_length(&self) -> Option<u64> {
match self.bounds_on_remaining_length() {
(lo, Some(hi)) if lo == hi => Some(lo),
_ => None,
}
}
#[allow(dead_code)] // used by a feature-gated `http-body`'s trait method
pub(crate) fn is_end_stream(&self) -> bool {
match &self.inner {
Inner::Once { inner: None } => true,
Inner::Once { inner: Some(bytes) } => bytes.is_empty(),
Inner::Dyn { inner: box_body } => match box_body {
#[cfg(feature = "http-body-0-4-x")]
BoxBody::HttpBody04(box_body) => {
use http_body_0_4::Body;
box_body.is_end_stream()
}
#[allow(unreachable_patterns)]
_ => unreachable!(
"enabling `http-body-0-4-x` is the only way to create the `Dyn` variant"
),
},
Inner::Taken => true,
}
}
pub(crate) fn bounds_on_remaining_length(&self) -> (u64, Option<u64>) {
match &self.inner {
Inner::Once { inner: None } => (0, Some(0)),
Inner::Once { inner: Some(bytes) } => {
let len = bytes.len() as u64;
(len, Some(len))
}
Inner::Dyn { inner: box_body } => match box_body {
#[cfg(feature = "http-body-0-4-x")]
BoxBody::HttpBody04(box_body) => {
use http_body_0_4::Body;
let hint = box_body.size_hint();
(hint.lower(), hint.upper())
}
#[allow(unreachable_patterns)]
_ => unreachable!(
"enabling `http-body-0-4-x` is the only way to create the `Dyn` variant"
),
},
Inner::Taken => (0, Some(0)),
}
}
/// Given a function to modify an `SdkBody`, run that function against this `SdkBody` before
/// returning the result.
pub fn map(self, f: impl Fn(SdkBody) -> SdkBody + Sync + Send + 'static) -> SdkBody {
if self.rebuild.is_some() {
SdkBody::retryable(move || f(self.try_clone().unwrap()))
} else {
f(self)
}
}
/// Update this `SdkBody` with `map`. **This function MUST NOT alter the data of the body.**
///
/// This function is useful for adding metadata like progress tracking to an [`SdkBody`] that
/// does not alter the actual byte data. If your mapper alters the contents of the body, use [`SdkBody::map`]
/// instead.
pub fn map_preserve_contents(
self,
f: impl Fn(SdkBody) -> SdkBody + Sync + Send + 'static,
) -> SdkBody {
let contents = self.bytes_contents.clone();
let mut out = if self.rebuild.is_some() {
SdkBody::retryable(move || f(self.try_clone().unwrap()))
} else {
f(self)
};
out.bytes_contents = contents;
out
}
}
impl From<&str> for SdkBody {
fn from(s: &str) -> Self {
Self::from(s.as_bytes())
}
}
impl From<Bytes> for SdkBody {
fn from(bytes: Bytes) -> Self {
let b = bytes.clone();
SdkBody {
inner: Inner::Once {
inner: Some(bytes.clone()),
},
rebuild: Some(Arc::new(move || Inner::Once {
inner: Some(bytes.clone()),
})),
bytes_contents: Some(b),
}
}
}
impl From<Vec<u8>> for SdkBody {
fn from(data: Vec<u8>) -> Self {
Self::from(Bytes::from(data))
}
}
impl From<String> for SdkBody {
fn from(s: String) -> Self {
Self::from(s.into_bytes())
}
}
impl From<&[u8]> for SdkBody {
fn from(data: &[u8]) -> Self {
Self::from(Bytes::copy_from_slice(data))
}
}
#[cfg(test)]
mod test {
use crate::body::SdkBody;
use std::pin::Pin;
#[test]
fn valid_size_hint() {
assert_eq!(SdkBody::from("hello").content_length(), Some(5));
assert_eq!(SdkBody::from("").content_length(), Some(0));
}
#[allow(clippy::bool_assert_comparison)]
#[test]
fn valid_eos() {
assert_eq!(SdkBody::from("hello").is_end_stream(), false);
assert_eq!(SdkBody::from("").is_end_stream(), true);
}
#[tokio::test]
async fn http_body_consumes_data() {
let mut body = SdkBody::from("hello!");
let mut body = Pin::new(&mut body);
assert!(!body.is_end_stream());
let data = body.next().await;
assert!(data.is_some());
let data = body.next().await;
assert!(data.is_none());
assert!(body.is_end_stream());
}
#[tokio::test]
async fn empty_body_returns_none() {
// Its important to avoid sending empty chunks of data to avoid H2 data frame problems
let mut body = SdkBody::from("");
let mut body = Pin::new(&mut body);
let data = body.next().await;
assert!(data.is_none());
}
#[test]
fn sdkbody_debug_once() {
let body = SdkBody::from("123");
assert!(format!("{:?}", body).contains("Once"));
}
#[test]
fn sdk_body_is_send() {
fn is_send<T: Send>() {}
is_send::<SdkBody>()
}
}