Salvo Response Compression

[dependencies]
salvo = { version = "0.89.3", features = ["compression"] }

Basic usage

Compression::new() enables all four algorithms (brotli, zstd, gzip, deflate) at Default level, with min_length = 1024 and a default text/* content-type allowlist.

use salvo::prelude::*;
use salvo::compression::Compression;

#[handler]
async fn body() -> String {
    "lorem ipsum ".repeat(200)
}

#[tokio::main]
async fn main() {
    let router = Router::new().hoop(Compression::new()).get(body);
    let acceptor = TcpListener::new("0.0.0.0:8080").bind().await;
    Server::new(acceptor).serve(router).await;
}

CompressionLevel

use salvo::compression::CompressionLevel;

CompressionLevel::Fastest      // speed > ratio
CompressionLevel::Default      // balanced
CompressionLevel::Minsize      // best ratio, slowest  (NOT `Best`)
CompressionLevel::Precise(6)   // algo-specific level

GOTCHA: the variant is Minsize, not Best.

Selecting algorithms

Enable/disable by name (each returns Self):

use salvo::compression::{Compression, CompressionLevel};

// Only gzip
let only_gzip = Compression::new()
    .disable_all()
    .enable_gzip(CompressionLevel::Default);

// Gzip + brotli, different levels
let mixed = Compression::new()
    .disable_all()
    .enable_brotli(CompressionLevel::Minsize)
    .enable_gzip(CompressionLevel::Fastest);

Available: enable_gzip, enable_brotli, enable_zstd, enable_deflate (plus matching disable_*).

min_length

Compression::new().min_length(2048);  // skip bodies smaller than 2KB

content_types

GOTCHA: content_types takes &[mime::Mime], NOT &[&str]. mime is re-exported at salvo::http::mime.

use salvo::compression::Compression;
use salvo::http::mime;

let comp = Compression::new().content_types(&[
    mime::TEXT_HTML,
    mime::TEXT_CSS,
    mime::APPLICATION_JSON,
    mime::APPLICATION_JAVASCRIPT,
    "image/svg+xml".parse().unwrap(),
]);

The default list already covers text/*, application/javascript, application/json, and image/svg+xml — only call content_types to restrict further.

Algorithm priority

By default, if the client accepts multiple encodings, the algorithm with the highest client q-value wins. Set force_priority(true) to use server preference order (brotli > zstd > gzip > deflate as inserted by new()).

Compression::new().force_priority(true);

Per-route compression

let static_comp = Compression::new()
    .disable_all()
    .enable_brotli(CompressionLevel::Minsize)
    .enable_gzip(CompressionLevel::Minsize);

let api_comp = Compression::new()
    .disable_all()
    .enable_gzip(CompressionLevel::Fastest)
    .min_length(256);

let router = Router::new()
    .push(Router::with_path("static/{**path}").hoop(static_comp).get(StaticDir::new("./public")))
    .push(Router::with_path("api/{**rest}").hoop(api_comp).get(api_handler));

Pre-compressed static assets

If you pre-compress files at build time (gzip -k9 bundle.js, brotli -k bundle.js), serve them with StaticDir which detects the pre-compressed variants automatically and serves them directly.

Related Skills

• salvo-static-files: serve pre-compressed files
• salvo-caching: combine with caching middleware