github.com/KKirillM/go-ethereum@v1.9.7/rpc/gzip.go (about)

     1  // Copyright 2019 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package rpc
    18  
    19  import (
    20  	"compress/gzip"
    21  	"io"
    22  	"io/ioutil"
    23  	"net/http"
    24  	"strings"
    25  	"sync"
    26  )
    27  
    28  var gzPool = sync.Pool{
    29  	New: func() interface{} {
    30  		w := gzip.NewWriter(ioutil.Discard)
    31  		return w
    32  	},
    33  }
    34  
    35  type gzipResponseWriter struct {
    36  	io.Writer
    37  	http.ResponseWriter
    38  }
    39  
    40  func (w *gzipResponseWriter) WriteHeader(status int) {
    41  	w.Header().Del("Content-Length")
    42  	w.ResponseWriter.WriteHeader(status)
    43  }
    44  
    45  func (w *gzipResponseWriter) Write(b []byte) (int, error) {
    46  	return w.Writer.Write(b)
    47  }
    48  
    49  func newGzipHandler(next http.Handler) http.Handler {
    50  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    51  		if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
    52  			next.ServeHTTP(w, r)
    53  			return
    54  		}
    55  
    56  		w.Header().Set("Content-Encoding", "gzip")
    57  
    58  		gz := gzPool.Get().(*gzip.Writer)
    59  		defer gzPool.Put(gz)
    60  
    61  		gz.Reset(w)
    62  		defer gz.Close()
    63  
    64  		next.ServeHTTP(&gzipResponseWriter{ResponseWriter: w, Writer: gz}, r)
    65  	})
    66  }