compress

Compress responses with gzip. The middleware negotiates with the client via Accept-Encoding and only kicks in for compressible content types above its MinLength threshold, so it's safe to mount unconditionally.

package main

import (
	"github.com/moonrhythm/parapet"
	"github.com/moonrhythm/parapet/pkg/compress"
)

func main() {
	s := parapet.New()
	s.Use(compress.Gzip())
	// s.Use(upstream.SingleHost(...)) — the handler whose responses get compressed.
}

Output:

Offer multiple encodings and let the client's Accept-Encoding pick. Each Compress self-skips when the client doesn't list its encoding or when the response is already encoded, so the INNERMOST middleware (the last Use, closest to the handler) compresses the response first and wins — the outer ones then see Content-Encoding already set and pass through. Order them least- to most-preferred: a client that accepts zstd gets zstd, else gzip, else deflate.

package main

import (
	"github.com/moonrhythm/parapet"
	"github.com/moonrhythm/parapet/pkg/compress"
)

func main() {
	s := parapet.New()
	s.Use(compress.Deflate()) // outermost: last-resort fallback
	s.Use(compress.Gzip())
	s.Use(compress.Zstd()) // innermost: runs first on the response, so zstd wins
}

Output:

Tune the compressor: pick a stronger zstd level and tighten which responses get compressed. Types is a space-separated MIME allow-list ("*" for all), and MinLength skips bodies whose Content-Length is below the threshold.

package main

import (
	"github.com/klauspost/compress/zstd"

	"github.com/moonrhythm/parapet"
	"github.com/moonrhythm/parapet/pkg/compress"
)

func main() {
	m := compress.ZstdWithLevel(zstd.SpeedBetterCompression)
	m.Types = "text/html text/css application/json"
	m.MinLength = 1024 // don't bother compressing tiny payloads
	m.Vary = true      // add Vary: Accept-Encoding so caches key on it

	s := parapet.New()
	s.Use(m)
}

Output: