liuwei3230 / gzip

Content-Type and Content-Length aware gzip middleware for Gin and net/http | 适用于Gin和net/http的gzip中间件。基于 Content-Type、Content-Length、扩展名等要素自动判断是否启用压缩。

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gzip

Content-Type and Content-Length aware gzip middleware for Gin and net/http.

Examples

Gin

import github.com/nanmu42/gzip

func main() {
	g := gin.Default()

    // use default settings
	g.Use(gzip.DefaultHandler().Gin)

	g.GET("/", func(c *gin.Context) {
		c.JSON(http.StatusOK, map[string]interface{}{
			"code": 0,
			"msg":  "hello",
			"data": fmt.Sprintf("l%sng!", strings.Repeat("o", 1000)),
		})
	})

	log.Println(g.Run(fmt.Sprintf(":%d", 3000)))
}

net/http

import github.com/nanmu42/gzip

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		writeString(w, fmt.Sprintf("This content is compressed: l%sng!", strings.Repeat("o", 1000)))
	})

    // wrap http.Handler using default settings
	log.Println(http.ListenAndServe(fmt.Sprintf(":%d", 3001), gzip.DefaultHandler().WrapHandler(mux)))
}

func writeString(w http.ResponseWriter, payload string) {
	w.Header().Set("Content-Type", "text/plain; charset=utf8")
	_, _ = io.WriteString(w, payload+"\n")
}

Customize Handler

Handler can be customized during initialization:

import github.com/nanmu42/gzip

handler := gzip.NewHandler(gzip.Config{
    // gzip compression level to use
	CompressionLevel: 6,
    // minimum content length to trigger gzip, the unit is in byte.
	MinContentLength: 256,
    // RequestFilter decide whether or not to compress response judging by request.
    // Filters are applied in the sequence here.
	RequestFilter: []RequestFilter{
	    NewCommonRequestFilter(),
	    DefaultExtensionFilter(),
	},
    // ResponseHeaderFilter decide whether or not to compress response
    // judging by request
	ResponseHeaderFilter: []ResponseHeaderFilter{
		NewSkipCompressedFilter(),
		DefaultContentTypeFilter(),
	},
})

RequestFilter and ResponseHeaderFilter are interfaces. You may define one that specially suits your need.

Limitation

• You should always provide a Content-Type in http response's header, as handler does not guess;
• handler looks up Content-Length in http response's header firstly, falls back to len(data) of the first http.ResponseWriter.Write(data []byte) calling. It may not use gzip if Content-Length is absent and len(data) is low.

If you are using Gin's c.JSON() or c.PureJSON(), you are safe from above limitation, as Gin sets proper Content-Type and write response in full length.

If you are using net/http, make sure above cases are considered.

Status: v0

API not stabilized, things may breaks.

You are welcome to try gzip on your test/unimportant environments.

Pull requests and issues are welcome.

Acknowledgement

During the development of this work, the author took following works/materials as reference:

• https://github.com/caddyserver/caddy/tree/master/caddyhttp/gzip (Apache License 2.0)
• https://github.com/gin-contrib/gzip (MIT License)
• https://blog.cloudflare.com/results-experimenting-brotli/
• https://support.cloudflare.com/hc/en-us/articles/200168396-What-will-Cloudflare-compress-

License

MIT License
Copyright (c) 2019 LI Zhennan

Caddy is licensed under the Apache License
Copyright 2015 Light Code Labs, LLC