/
gzip.go
136 lines (103 loc) · 2.88 KB
/
gzip.go
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package middleware
import (
"bufio"
"compress/gzip"
"io"
"io/ioutil"
"net"
"net/http"
"strings"
"sync"
"github.com/go-playground/lars"
)
type gzipWriter struct {
io.Writer
http.ResponseWriter
sniffComplete bool
}
func (w *gzipWriter) Write(b []byte) (int, error) {
if !w.sniffComplete {
if w.Header().Get(lars.ContentType) == "" {
w.Header().Set(lars.ContentType, http.DetectContentType(b))
}
w.sniffComplete = true
}
return w.Writer.Write(b)
}
func (w *gzipWriter) Flush() error {
return w.Writer.(*gzip.Writer).Flush()
}
func (w *gzipWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
return w.ResponseWriter.(http.Hijacker).Hijack()
}
func (w *gzipWriter) CloseNotify() <-chan bool {
return w.ResponseWriter.(http.CloseNotifier).CloseNotify()
}
var writerPool = sync.Pool{
New: func() interface{} {
return &gzipWriter{Writer: gzip.NewWriter(ioutil.Discard)}
},
}
// Gzip returns a middleware which compresses HTTP response using gzip compression
// scheme.
func Gzip(c lars.Context) {
c.Response().Header().Add(lars.Vary, lars.AcceptEncoding)
if strings.Contains(c.Request().Header.Get(lars.AcceptEncoding), lars.Gzip) {
gw := writerPool.Get().(*gzipWriter)
gw.sniffComplete = false
w := gw.Writer.(*gzip.Writer)
w.Reset(c.Response().Writer())
gw.ResponseWriter = c.Response().Writer()
defer func() {
if !gw.sniffComplete {
// We have to reset response to it's pristine state when
// nothing is written to body.
c.Response().Header().Del(lars.ContentEncoding)
w.Reset(ioutil.Discard)
}
w.Close()
writerPool.Put(gw)
}()
c.Response().Header().Set(lars.ContentEncoding, lars.Gzip)
c.Response().SetWriter(gw)
}
c.Next()
}
// GzipLevel returns a middleware which compresses HTTP response using gzip compression
// scheme using the level specified
func GzipLevel(level int) lars.HandlerFunc {
// test gzip level, then don't have to each time one is created
// in the pool
if _, err := gzip.NewWriterLevel(ioutil.Discard, level); err != nil {
panic(err)
}
var pool = sync.Pool{
New: func() interface{} {
z, _ := gzip.NewWriterLevel(ioutil.Discard, level)
return &gzipWriter{Writer: z}
},
}
return func(c lars.Context) {
c.Response().Header().Add(lars.Vary, lars.AcceptEncoding)
if strings.Contains(c.Request().Header.Get(lars.AcceptEncoding), lars.Gzip) {
gw := pool.Get().(*gzipWriter)
gw.sniffComplete = false
w := gw.Writer.(*gzip.Writer)
w.Reset(c.Response().Writer())
gw.ResponseWriter = c.Response().Writer()
defer func() {
if !gw.sniffComplete {
// We have to reset response to it's pristine state when
// nothing is written to body.
c.Response().Header().Del(lars.ContentEncoding)
w.Reset(ioutil.Discard)
}
w.Close()
pool.Put(gw)
}()
c.Response().Header().Set(lars.ContentEncoding, lars.Gzip)
c.Response().SetWriter(gw)
}
c.Next()
}
}