Module compression

Middleware that compresses response bodies.

Example

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

use bytes::Bytes;
use futures_lite::stream::StreamExt;
use rama_core::error::BoxError;
use rama_http::dep::http_body::Frame;
use rama_http::dep::http_body_util::{BodyExt , StreamBody};
use rama_http::dep::http_body_util::combinators::BoxBody as InnerBoxBody;
use rama_http::layer::compression::CompressionLayer;
use rama_http::{Body, Request, Response, header::ACCEPT_ENCODING};
use rama_core::service::service_fn;
use rama_core::{Context, Service, Layer};
use std::convert::Infallible;
use tokio::fs::{self, File};
use tokio_util::io::ReaderStream;

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

async fn handle(req: Request) -> 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(|res| match res {
        Ok(v) => Ok(Frame::data(v)),
        Err(e) => Err(e),
    });
    // 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 = BodyExt::boxed(body);
    // Create response.
    Ok(Response::new(body))
}

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

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

let response = service
    .serve(Context::default(), 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.

Enums

CompressionLevel

Level of compression data should be compressed with.

Traits

Predicate

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