Struct Compress

#[non_exhaustive]
pub struct Compress;

Middleware for compressing response payloads.

Encoding Negotiation

Compress will read the Accept-Encoding header to negotiate which compression codec to use. Payloads are not compressed if the header is not sent. The compress-* feature flags are also considered in this selection process.

Pre-compressed Payload

If you are serving some data that is already using a compressed representation (e.g., a gzip compressed HTML file from disk) you can signal this to Compress by setting an appropriate Content-Encoding header. In addition to preventing double compressing the payload, this header is required by the spec when using compressed representations and will inform the client that the content should be uncompressed.

However, it is not advised to unconditionally serve encoded representations of content because the client may not support it. The AcceptEncoding typed header has some utilities to help perform manual encoding negotiation, if required. When negotiating content encoding, it is also required by the spec to send a Vary: Accept-Encoding header.

A (naïve) example serving an pre-compressed Gzip file is included below.

Examples

To enable automatic payload compression just include Compress as a top-level middleware:

use actix_web::{middleware, web, App, HttpResponse};

let app = App::new()
    .wrap(middleware::Compress::default())
    .default_service(web::to(|| async { HttpResponse::Ok().body("hello world") }));

Pre-compressed Gzip file being served from disk with correct headers added to bypass middleware:

use actix_web::{middleware, http::header, web, App, HttpResponse, Responder};

async fn index_handler() -> actix_web::Result<impl Responder> {
    Ok(actix_files::NamedFile::open_async("./assets/index.html.gz").await?
        .customize()
        .insert_header(header::ContentEncoding::Gzip))
}

let app = App::new()
    .wrap(middleware::Compress::default())
    .default_service(web::to(index_handler));

Trait Implementations

impl Clone for Compress

fn clone(&self) -> Compress

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Compress

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

Formats the value using the given formatter.

impl Default for Compress

fn default() -> Compress

Returns the “default value” for a type.

impl<S, B> Transform<S, ServiceRequest> for Compress

where B: MessageBody, S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,

type Response = ServiceResponse<EitherBody<Encoder<B>>>

Responses produced by the service.

type Error = Error

Errors produced by the service.

type Transform = CompressMiddleware<S>

The TransformService value created by this factory

type InitError = ()

Errors produced while building a transform service.

type Future = Ready<Result<<Compress as Transform<S, ServiceRequest>>::Transform, <Compress as Transform<S, ServiceRequest>>::InitError>>

The future response value.

fn new_transform(&self, service: S) -> Self::Future

Creates and returns a new Transform component, asynchronously