Copyright 2018 The Go Authors. All rights reserved. Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
Package httpguts provides functions implementing various details of the HTTP specification. This package is shared by the standard library (which vendors it) and x/net/http2. It comes with no API stability promise.
package httpguts

import (
	
	
)
ValidTrailerHeader reports whether name is a valid header field name to appear in trailers. See RFC 7230, Section 4.1.2
func ( string) bool {
	 = textproto.CanonicalMIMEHeaderKey()
	if strings.HasPrefix(, "If-") || badTrailer[] {
		return false
	}
	return true
}

var badTrailer = map[string]bool{
	"Authorization":       true,
	"Cache-Control":       true,
	"Connection":          true,
	"Content-Encoding":    true,
	"Content-Length":      true,
	"Content-Range":       true,
	"Content-Type":        true,
	"Expect":              true,
	"Host":                true,
	"Keep-Alive":          true,
	"Max-Forwards":        true,
	"Pragma":              true,
	"Proxy-Authenticate":  true,
	"Proxy-Authorization": true,
	"Proxy-Connection":    true,
	"Range":               true,
	"Realm":               true,
	"Te":                  true,
	"Trailer":             true,
	"Transfer-Encoding":   true,
	"Www-Authenticate":    true,