http-response-compression

A Tower middleware layer for compressing HTTP response bodies.

Features

• Supports Zstd, Brotli, Gzip, and Deflate compression
• Automatic codec selection based on Accept-Encoding header
• Configurable minimum body size threshold (default: 860 bytes)
• Streaming support with flush control for SSE and gRPC-web
• Preserves trailers through compression

Usage

use http_response_compression::CompressionLayer;
use tower::ServiceBuilder;

let service = ServiceBuilder::new()
    .layer(CompressionLayer::new())
    .service(my_service);

With custom minimum size:

let service = ServiceBuilder::new()
    .layer(CompressionLayer::new().min_size(1024))
    .service(my_service);

Compression Rules

The middleware will not compress responses when:

• No supported Accept-Encoding is present in the request
• Content-Encoding header is already set
• Content-Range header is present (range responses)
• Content-Type is image/* (except image/svg+xml)
• Content-Type is application/grpc (except application/grpc-web)
• Content-Length is below the minimum size threshold

The middleware will always flush after each chunk when:

• X-Accel-Buffering: no header is present
• Content-Type is text/event-stream
• Content-Type is application/grpc-web

Response Modifications

When compression is applied:

• Content-Encoding header is set to the codec used
• Content-Length header is removed (compressed size is unknown)
• Accept-Ranges header is removed
• Vary header includes Accept-Encoding

License

MIT