vendor/golang.org/x/net/http/httpguts/guts.go

   1 // Copyright 2018 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // Package httpguts provides functions implementing various details
   6 // of the HTTP specification.
   7 //
   8 // This package is shared by the standard library (which vendors it)
   9 // and x/net/http2. It comes with no API stability promise.
  10 package httpguts
  11
  12 import (
  13         "net/textproto"
  14         "strings"
  15 )
  16
  17 // ValidTrailerHeader reports whether name is a valid header field name to appear
  18 // in trailers.
  19 // See RFC 7230, Section 4.1.2
  20 func ValidTrailerHeader(name string) bool {
  21         name = textproto.CanonicalMIMEHeaderKey(name)
  22         if strings.HasPrefix(name, "If-") || badTrailer[name] {
  23                 return false
  24         }
  25         return true
  26 }
  27
  28 var badTrailer = map[string]bool{
  29         "Authorization":       true,
  30         "Cache-Control":       true,
  31         "Connection":          true,
  32         "Content-Encoding":    true,
  33         "Content-Length":      true,
  34         "Content-Range":       true,
  35         "Content-Type":        true,
  36         "Expect":              true,
  37         "Host":                true,
  38         "Keep-Alive":          true,
  39         "Max-Forwards":        true,
  40         "Pragma":              true,
  41         "Proxy-Authenticate":  true,
  42         "Proxy-Authorization": true,
  43         "Proxy-Connection":    true,
  44         "Range":               true,
  45         "Realm":               true,
  46         "Te":                  true,
  47         "Trailer":             true,
  48         "Transfer-Encoding":   true,
  49         "Www-Authenticate":    true,
  50 }