Module tower_http::compression

Available on crate features compression-br or compression-deflate or compression-gzip or compression-zstd only.

Middleware that compresses response bodies.

Example

Example showing how to respond with the compressed contents of a file.

use bytes::{Bytes, BytesMut};
use http::{Request, Response, header::ACCEPT_ENCODING};
use http_body_util::{Full, BodyExt, StreamBody, combinators::UnsyncBoxBody};
use http_body::Frame;
use std::convert::Infallible;
use tokio::fs::{self, File};
use tokio_util::io::ReaderStream;
use tower::{Service, ServiceExt, ServiceBuilder, service_fn};
use tower_http::{compression::CompressionLayer, BoxError};
use futures_util::TryStreamExt;

type BoxBody = UnsyncBoxBody<Bytes, std::io::Error>;

async fn handle(req: Request<Full<Bytes>>) -> Result<Response<BoxBody>, Infallible> {
    // Open the file.
    let file = File::open("Cargo.toml").await.expect("file missing");
    // Convert the file into a `Stream` of `Bytes`.
    let stream = ReaderStream::new(file);
    // Convert the stream into a stream of data `Frame`s.
    let stream = stream.map_ok(Frame::data);
    // Convert the `Stream` into a `Body`.
    let body = StreamBody::new(stream);
    // Erase the type because its very hard to name in the function signature.
    let body = body.boxed_unsync();
    // Create response.
    Ok(Response::new(body))
}

let mut service = ServiceBuilder::new()
    // Compress responses based on the `Accept-Encoding` header.
    .layer(CompressionLayer::new())
    .service_fn(handle);

// Call the service.
let request = Request::builder()
    .header(ACCEPT_ENCODING, "gzip")
    .body(Full::<Bytes>::default())?;

let response = service
    .ready()
    .await?
    .call(request)
    .await?;

assert_eq!(response.headers()["content-encoding"], "gzip");

// Read the body
let bytes = response
    .into_body()
    .collect()
    .await?
    .to_bytes();

// The compressed body should be smaller 🤞
let uncompressed_len = fs::read_to_string("Cargo.toml").await?.len();
assert!(bytes.len() < uncompressed_len);

Modules

• predicate
  Predicates for disabling compression of responses.

Structs

• Compression
  Compress response bodies of the underlying service.
• CompressionBody
  Response body of Compression.
• CompressionLayer
  Compress response bodies of the underlying service.
• DefaultPredicate
  The default predicate used by Compression and CompressionLayer.
• ResponseFuture
  Response future of Compression.

Enums

• CompressionLevelcompression-br or compression-deflate or compression-gzip or compression-zstd or decompression-br or decompression-deflate or decompression-gzip or decompression-zstd
  Level of compression data should be compressed with.

Traits

• Predicate
  Predicate used to determine if a response should be compressed or not.