mirror of
https://github.com/ergochat/ergo.git
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284 lines
5.4 KiB
Go
284 lines
5.4 KiB
Go
// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package websocket
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import (
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"crypto/rand"
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"crypto/sha1"
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"encoding/base64"
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"io"
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"net/http"
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"strings"
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"unicode/utf8"
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)
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var keyGUID = []byte("258EAFA5-E914-47DA-95CA-C5AB0DC85B11")
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func computeAcceptKey(challengeKey string) string {
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h := sha1.New()
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h.Write([]byte(challengeKey))
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h.Write(keyGUID)
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return base64.StdEncoding.EncodeToString(h.Sum(nil))
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}
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func generateChallengeKey() (string, error) {
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p := make([]byte, 16)
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if _, err := io.ReadFull(rand.Reader, p); err != nil {
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return "", err
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}
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return base64.StdEncoding.EncodeToString(p), nil
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}
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// Token octets per RFC 2616.
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var isTokenOctet = [256]bool{
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'!': true,
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'#': true,
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'$': true,
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'%': true,
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'&': true,
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'\'': true,
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'*': true,
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'+': true,
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'-': true,
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'.': true,
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'0': true,
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'1': true,
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'2': true,
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'3': true,
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'4': true,
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'5': true,
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'6': true,
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'7': true,
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'8': true,
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'9': true,
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'A': true,
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'B': true,
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'C': true,
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'D': true,
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'E': true,
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'F': true,
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'G': true,
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'H': true,
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'I': true,
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'J': true,
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'K': true,
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'L': true,
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'M': true,
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'N': true,
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'O': true,
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'P': true,
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'Q': true,
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'R': true,
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'S': true,
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'T': true,
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'U': true,
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'W': true,
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'V': true,
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'X': true,
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'Y': true,
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'Z': true,
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'^': true,
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'_': true,
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'`': true,
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'a': true,
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'b': true,
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'c': true,
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'd': true,
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'e': true,
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'f': true,
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'g': true,
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'h': true,
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'i': true,
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'j': true,
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'k': true,
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'l': true,
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'm': true,
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'n': true,
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'o': true,
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'p': true,
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'q': true,
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'r': true,
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's': true,
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't': true,
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'u': true,
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'v': true,
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'w': true,
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'x': true,
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'y': true,
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'z': true,
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'|': true,
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'~': true,
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}
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// skipSpace returns a slice of the string s with all leading RFC 2616 linear
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// whitespace removed.
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func skipSpace(s string) (rest string) {
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i := 0
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for ; i < len(s); i++ {
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if b := s[i]; b != ' ' && b != '\t' {
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break
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}
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}
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return s[i:]
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}
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// nextToken returns the leading RFC 2616 token of s and the string following
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// the token.
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func nextToken(s string) (token, rest string) {
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i := 0
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for ; i < len(s); i++ {
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if !isTokenOctet[s[i]] {
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break
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}
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}
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return s[:i], s[i:]
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}
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// nextTokenOrQuoted returns the leading token or quoted string per RFC 2616
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// and the string following the token or quoted string.
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func nextTokenOrQuoted(s string) (value string, rest string) {
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if !strings.HasPrefix(s, "\"") {
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return nextToken(s)
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}
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s = s[1:]
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for i := 0; i < len(s); i++ {
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switch s[i] {
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case '"':
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return s[:i], s[i+1:]
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case '\\':
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p := make([]byte, len(s)-1)
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j := copy(p, s[:i])
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escape := true
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for i = i + 1; i < len(s); i++ {
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b := s[i]
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switch {
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case escape:
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escape = false
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p[j] = b
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j++
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case b == '\\':
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escape = true
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case b == '"':
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return string(p[:j]), s[i+1:]
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default:
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p[j] = b
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j++
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}
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}
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return "", ""
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}
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}
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return "", ""
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}
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// equalASCIIFold returns true if s is equal to t with ASCII case folding as
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// defined in RFC 4790.
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func equalASCIIFold(s, t string) bool {
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for s != "" && t != "" {
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sr, size := utf8.DecodeRuneInString(s)
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s = s[size:]
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tr, size := utf8.DecodeRuneInString(t)
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t = t[size:]
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if sr == tr {
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continue
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}
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if 'A' <= sr && sr <= 'Z' {
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sr = sr + 'a' - 'A'
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}
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if 'A' <= tr && tr <= 'Z' {
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tr = tr + 'a' - 'A'
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}
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if sr != tr {
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return false
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}
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}
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return s == t
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}
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// tokenListContainsValue returns true if the 1#token header with the given
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// name contains a token equal to value with ASCII case folding.
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func tokenListContainsValue(header http.Header, name string, value string) bool {
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headers:
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for _, s := range header[name] {
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for {
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var t string
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t, s = nextToken(skipSpace(s))
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if t == "" {
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continue headers
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}
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s = skipSpace(s)
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if s != "" && s[0] != ',' {
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continue headers
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}
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if equalASCIIFold(t, value) {
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return true
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}
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if s == "" {
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continue headers
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}
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s = s[1:]
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}
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}
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return false
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}
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// parseExtensions parses WebSocket extensions from a header.
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func parseExtensions(header http.Header) []map[string]string {
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// From RFC 6455:
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//
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// Sec-WebSocket-Extensions = extension-list
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// extension-list = 1#extension
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// extension = extension-token *( ";" extension-param )
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// extension-token = registered-token
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// registered-token = token
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// extension-param = token [ "=" (token | quoted-string) ]
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// ;When using the quoted-string syntax variant, the value
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// ;after quoted-string unescaping MUST conform to the
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// ;'token' ABNF.
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var result []map[string]string
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headers:
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for _, s := range header["Sec-Websocket-Extensions"] {
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for {
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var t string
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t, s = nextToken(skipSpace(s))
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if t == "" {
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continue headers
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}
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ext := map[string]string{"": t}
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for {
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s = skipSpace(s)
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if !strings.HasPrefix(s, ";") {
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break
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}
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var k string
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k, s = nextToken(skipSpace(s[1:]))
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if k == "" {
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continue headers
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}
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s = skipSpace(s)
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var v string
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if strings.HasPrefix(s, "=") {
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v, s = nextTokenOrQuoted(skipSpace(s[1:]))
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s = skipSpace(s)
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}
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if s != "" && s[0] != ',' && s[0] != ';' {
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continue headers
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}
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ext[k] = v
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}
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if s != "" && s[0] != ',' {
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continue headers
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}
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result = append(result, ext)
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if s == "" {
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continue headers
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}
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s = s[1:]
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}
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}
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return result
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}
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