122 lines
2.8 KiB
Go
122 lines
2.8 KiB
Go
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package middleware
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import (
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"bufio"
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"compress/gzip"
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"io"
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"io/ioutil"
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"net"
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"net/http"
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"strings"
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"github.com/labstack/echo"
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)
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type (
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// GzipConfig defines the config for Gzip middleware.
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GzipConfig struct {
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// Skipper defines a function to skip middleware.
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Skipper Skipper
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// Gzip compression level.
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// Optional. Default value -1.
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Level int `json:"level"`
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}
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gzipResponseWriter struct {
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io.Writer
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http.ResponseWriter
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}
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)
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const (
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gzipScheme = "gzip"
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)
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var (
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// DefaultGzipConfig is the default Gzip middleware config.
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DefaultGzipConfig = GzipConfig{
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Skipper: DefaultSkipper,
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Level: -1,
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}
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)
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// Gzip returns a middleware which compresses HTTP response using gzip compression
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// scheme.
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func Gzip() echo.MiddlewareFunc {
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return GzipWithConfig(DefaultGzipConfig)
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}
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// GzipWithConfig return Gzip middleware with config.
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// See: `Gzip()`.
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func GzipWithConfig(config GzipConfig) echo.MiddlewareFunc {
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// Defaults
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if config.Skipper == nil {
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config.Skipper = DefaultGzipConfig.Skipper
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}
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if config.Level == 0 {
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config.Level = DefaultGzipConfig.Level
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}
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return func(next echo.HandlerFunc) echo.HandlerFunc {
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return func(c echo.Context) error {
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if config.Skipper(c) {
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return next(c)
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}
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res := c.Response()
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res.Header().Add(echo.HeaderVary, echo.HeaderAcceptEncoding)
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if strings.Contains(c.Request().Header.Get(echo.HeaderAcceptEncoding), gzipScheme) {
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res.Header().Add(echo.HeaderContentEncoding, gzipScheme) // Issue #806
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rw := res.Writer
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w, err := gzip.NewWriterLevel(rw, config.Level)
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if err != nil {
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return err
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}
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defer func() {
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if res.Size == 0 {
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if res.Header().Get(echo.HeaderContentEncoding) == gzipScheme {
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res.Header().Del(echo.HeaderContentEncoding)
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}
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// We have to reset response to it's pristine state when
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// nothing is written to body or error is returned.
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// See issue #424, #407.
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res.Writer = rw
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w.Reset(ioutil.Discard)
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}
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w.Close()
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}()
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grw := &gzipResponseWriter{Writer: w, ResponseWriter: rw}
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res.Writer = grw
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}
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return next(c)
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}
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}
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}
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func (w *gzipResponseWriter) WriteHeader(code int) {
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if code == http.StatusNoContent { // Issue #489
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w.ResponseWriter.Header().Del(echo.HeaderContentEncoding)
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}
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w.ResponseWriter.WriteHeader(code)
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}
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func (w *gzipResponseWriter) Write(b []byte) (int, error) {
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if w.Header().Get(echo.HeaderContentType) == "" {
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w.Header().Set(echo.HeaderContentType, http.DetectContentType(b))
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}
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return w.Writer.Write(b)
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}
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func (w *gzipResponseWriter) Flush() {
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w.Writer.(*gzip.Writer).Flush()
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}
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func (w *gzipResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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return w.ResponseWriter.(http.Hijacker).Hijack()
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}
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func (w *gzipResponseWriter) CloseNotify() <-chan bool {
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return w.ResponseWriter.(http.CloseNotifier).CloseNotify()
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}
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