github.com/google/martian/v3@v3.3.3/header/hopbyhop_modifier.go (about)

     1  // Copyright 2015 Google Inc. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package header
    16  
    17  import (
    18  	"net/http"
    19  	"strings"
    20  
    21  	"github.com/google/martian/v3"
    22  )
    23  
    24  // Hop-by-hop headers as defined by RFC2616.
    25  //
    26  // http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3.1
    27  var hopByHopHeaders = []string{
    28  	"Connection",
    29  	"Keep-Alive",
    30  	"Proxy-Authenticate",
    31  	"Proxy-Authorization",
    32  	"Proxy-Connection", // Non-standard, but required for HTTP/2.
    33  	"Te",
    34  	"Trailer",
    35  	"Transfer-Encoding",
    36  	"Upgrade",
    37  }
    38  
    39  type hopByHopModifier struct{}
    40  
    41  // NewHopByHopModifier removes Hop-By-Hop headers from requests and
    42  // responses.
    43  func NewHopByHopModifier() martian.RequestResponseModifier {
    44  	return &hopByHopModifier{}
    45  }
    46  
    47  // ModifyRequest removes all hop-by-hop headers defined by RFC2616 as
    48  // well as any additional hop-by-hop headers specified in the
    49  // Connection header.
    50  func (m *hopByHopModifier) ModifyRequest(req *http.Request) error {
    51  	removeHopByHopHeaders(req.Header)
    52  	return nil
    53  }
    54  
    55  // ModifyResponse removes all hop-by-hop headers defined by RFC2616 as
    56  // well as any additional hop-by-hop headers specified in the
    57  // Connection header.
    58  func (m *hopByHopModifier) ModifyResponse(res *http.Response) error {
    59  	removeHopByHopHeaders(res.Header)
    60  	return nil
    61  }
    62  
    63  func removeHopByHopHeaders(header http.Header) {
    64  	// Additional hop-by-hop headers may be specified in `Connection` headers.
    65  	// http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-9.1
    66  	for _, vs := range header["Connection"] {
    67  		for _, v := range strings.Split(vs, ",") {
    68  			k := http.CanonicalHeaderKey(strings.TrimSpace(v))
    69  			header.Del(k)
    70  		}
    71  	}
    72  
    73  	for _, k := range hopByHopHeaders {
    74  		header.Del(k)
    75  	}
    76  }