| // Copyright 2009 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 http |
| |
| import ( |
| "strings" |
| "unicode/utf8" |
| ) |
| |
| // This file deals with lexical matters of HTTP |
| |
| var isTokenTable = [127]bool{ |
| '!': true, |
| '#': true, |
| '$': true, |
| '%': true, |
| '&': true, |
| '\'': true, |
| '*': true, |
| '+': true, |
| '-': true, |
| '.': true, |
| '0': true, |
| '1': true, |
| '2': true, |
| '3': true, |
| '4': true, |
| '5': true, |
| '6': true, |
| '7': true, |
| '8': true, |
| '9': true, |
| 'A': true, |
| 'B': true, |
| 'C': true, |
| 'D': true, |
| 'E': true, |
| 'F': true, |
| 'G': true, |
| 'H': true, |
| 'I': true, |
| 'J': true, |
| 'K': true, |
| 'L': true, |
| 'M': true, |
| 'N': true, |
| 'O': true, |
| 'P': true, |
| 'Q': true, |
| 'R': true, |
| 'S': true, |
| 'T': true, |
| 'U': true, |
| 'W': true, |
| 'V': true, |
| 'X': true, |
| 'Y': true, |
| 'Z': true, |
| '^': true, |
| '_': true, |
| '`': true, |
| 'a': true, |
| 'b': true, |
| 'c': true, |
| 'd': true, |
| 'e': true, |
| 'f': true, |
| 'g': true, |
| 'h': true, |
| 'i': true, |
| 'j': true, |
| 'k': true, |
| 'l': true, |
| 'm': true, |
| 'n': true, |
| 'o': true, |
| 'p': true, |
| 'q': true, |
| 'r': true, |
| 's': true, |
| 't': true, |
| 'u': true, |
| 'v': true, |
| 'w': true, |
| 'x': true, |
| 'y': true, |
| 'z': true, |
| '|': true, |
| '~': true, |
| } |
| |
| func isToken(r rune) bool { |
| i := int(r) |
| return i < len(isTokenTable) && isTokenTable[i] |
| } |
| |
| func isNotToken(r rune) bool { |
| return !isToken(r) |
| } |
| |
| // headerValuesContainsToken reports whether any string in values |
| // contains the provided token, ASCII case-insensitively. |
| func headerValuesContainsToken(values []string, token string) bool { |
| for _, v := range values { |
| if headerValueContainsToken(v, token) { |
| return true |
| } |
| } |
| return false |
| } |
| |
| // isOWS reports whether b is an optional whitespace byte, as defined |
| // by RFC 7230 section 3.2.3. |
| func isOWS(b byte) bool { return b == ' ' || b == '\t' } |
| |
| // trimOWS returns x with all optional whitespace removes from the |
| // beginning and end. |
| func trimOWS(x string) string { |
| // TODO: consider using strings.Trim(x, " \t") instead, |
| // if and when it's fast enough. See issue 10292. |
| // But this ASCII-only code will probably always beat UTF-8 |
| // aware code. |
| for len(x) > 0 && isOWS(x[0]) { |
| x = x[1:] |
| } |
| for len(x) > 0 && isOWS(x[len(x)-1]) { |
| x = x[:len(x)-1] |
| } |
| return x |
| } |
| |
| // headerValueContainsToken reports whether v (assumed to be a |
| // 0#element, in the ABNF extension described in RFC 7230 section 7) |
| // contains token amongst its comma-separated tokens, ASCII |
| // case-insensitively. |
| func headerValueContainsToken(v string, token string) bool { |
| v = trimOWS(v) |
| if comma := strings.IndexByte(v, ','); comma != -1 { |
| return tokenEqual(trimOWS(v[:comma]), token) || headerValueContainsToken(v[comma+1:], token) |
| } |
| return tokenEqual(v, token) |
| } |
| |
| // lowerASCII returns the ASCII lowercase version of b. |
| func lowerASCII(b byte) byte { |
| if 'A' <= b && b <= 'Z' { |
| return b + ('a' - 'A') |
| } |
| return b |
| } |
| |
| // tokenEqual reports whether t1 and t2 are equal, ASCII case-insensitively. |
| func tokenEqual(t1, t2 string) bool { |
| if len(t1) != len(t2) { |
| return false |
| } |
| for i, b := range t1 { |
| if b >= utf8.RuneSelf { |
| // No UTF-8 or non-ASCII allowed in tokens. |
| return false |
| } |
| if lowerASCII(byte(b)) != lowerASCII(t2[i]) { |
| return false |
| } |
| } |
| return true |
| } |
| |
| // isLWS reports whether b is linear white space, according |
| // to http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2 |
| // LWS = [CRLF] 1*( SP | HT ) |
| func isLWS(b byte) bool { return b == ' ' || b == '\t' } |
| |
| // isCTL reports whether b is a control byte, according |
| // to http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2 |
| // CTL = <any US-ASCII control character |
| // (octets 0 - 31) and DEL (127)> |
| func isCTL(b byte) bool { |
| const del = 0x7f // a CTL |
| return b < ' ' || b == del |
| } |