mirror of
https://github.com/prometheus/prometheus.git
synced 2024-11-18 03:24:05 -08:00
93 lines
2.8 KiB
Go
93 lines
2.8 KiB
Go
// Copyright 2013 The Prometheus Authors
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package httputil
|
|
|
|
import (
|
|
"compress/gzip"
|
|
"compress/zlib"
|
|
"io"
|
|
"net/http"
|
|
"strings"
|
|
)
|
|
|
|
const (
|
|
acceptEncodingHeader = "Accept-Encoding"
|
|
contentEncodingHeader = "Content-Encoding"
|
|
gzipEncoding = "gzip"
|
|
deflateEncoding = "deflate"
|
|
)
|
|
|
|
// Wrapper around http.Handler which adds suitable response compression based
|
|
// on the client's Accept-Encoding headers.
|
|
type compressedResponseWriter struct {
|
|
http.ResponseWriter
|
|
writer io.Writer
|
|
}
|
|
|
|
// Writes HTTP response content data.
|
|
func (c *compressedResponseWriter) Write(p []byte) (int, error) {
|
|
return c.writer.Write(p)
|
|
}
|
|
|
|
// Closes the compressedResponseWriter and ensures to flush all data before.
|
|
func (c *compressedResponseWriter) Close() {
|
|
if zlibWriter, ok := c.writer.(*zlib.Writer); ok {
|
|
zlibWriter.Flush()
|
|
}
|
|
if gzipWriter, ok := c.writer.(*gzip.Writer); ok {
|
|
gzipWriter.Flush()
|
|
}
|
|
if closer, ok := c.writer.(io.Closer); ok {
|
|
defer closer.Close()
|
|
}
|
|
}
|
|
|
|
// Constructs a new compressedResponseWriter based on client request headers.
|
|
func newCompressedResponseWriter(writer http.ResponseWriter, req *http.Request) *compressedResponseWriter {
|
|
encodings := strings.Split(req.Header.Get(acceptEncodingHeader), ",")
|
|
for _, encoding := range encodings {
|
|
switch strings.TrimSpace(encoding) {
|
|
case gzipEncoding:
|
|
writer.Header().Set(contentEncodingHeader, gzipEncoding)
|
|
return &compressedResponseWriter{
|
|
ResponseWriter: writer,
|
|
writer: gzip.NewWriter(writer),
|
|
}
|
|
case deflateEncoding:
|
|
writer.Header().Set(contentEncodingHeader, deflateEncoding)
|
|
return &compressedResponseWriter{
|
|
ResponseWriter: writer,
|
|
writer: zlib.NewWriter(writer),
|
|
}
|
|
}
|
|
}
|
|
return &compressedResponseWriter{
|
|
ResponseWriter: writer,
|
|
writer: writer,
|
|
}
|
|
}
|
|
|
|
// CompressionHandler is a wrapper around http.Handler which adds suitable
|
|
// response compression based on the client's Accept-Encoding headers.
|
|
type CompressionHandler struct {
|
|
Handler http.Handler
|
|
}
|
|
|
|
// ServeHTTP adds compression to the original http.Handler's ServeHTTP() method.
|
|
func (c CompressionHandler) ServeHTTP(writer http.ResponseWriter, req *http.Request) {
|
|
compWriter := newCompressedResponseWriter(writer, req)
|
|
c.Handler.ServeHTTP(compWriter, req)
|
|
compWriter.Close()
|
|
}
|