1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/*!
* vary
* Copyright(c) 2014-2017 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module exports.
*/
module.exports = vary
module.exports.append = append
/**
* RegExp to match field-name in RFC 7230 sec 3.2
*
* field-name = token
* token = 1*tchar
* tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*"
* / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
* / DIGIT / ALPHA
* ; any VCHAR, except delimiters
*/
var FIELD_NAME_REGEXP = /^[!#$%&'*+\-.^_`|~0-9A-Za-z]+$/
/**
* Append a field to a vary header.
*
* @param {String} header
* @param {String|Array} field
* @return {String}
* @public
*/
function append (header, field) {
if (typeof header !== 'string') {
throw new TypeError('header argument is required')
}
if (!field) {
throw new TypeError('field argument is required')
}
// get fields array
var fields = !Array.isArray(field)
? parse(String(field))
: field
// assert on invalid field names
for (var j = 0; j < fields.length; j++) {
if (!FIELD_NAME_REGEXP.test(fields[j])) {
throw new TypeError('field argument contains an invalid header name')
}
}
// existing, unspecified vary
if (header === '*') {
return header
}
// enumerate current values
var val = header
var vals = parse(header.toLowerCase())
// unspecified vary
if (fields.indexOf('*') !== -1 || vals.indexOf('*') !== -1) {
return '*'
}
for (var i = 0; i < fields.length; i++) {
var fld = fields[i].toLowerCase()
// append value (case-preserving)
if (vals.indexOf(fld) === -1) {
vals.push(fld)
val = val
? val + ', ' + fields[i]
: fields[i]
}
}
return val
}
/**
* Parse a vary header into an array.
*
* @param {String} header
* @return {Array}
* @private
*/
function parse (header) {
var end = 0
var list = []
var start = 0
// gather tokens
for (var i = 0, len = header.length; i < len; i++) {
switch (header.charCodeAt(i)) {
case 0x20: /* */
if (start === end) {
start = end = i + 1
}
break
case 0x2c: /* , */
list.push(header.substring(start, end))
start = end = i + 1
break
default:
end = i + 1
break
}
}
// final token
list.push(header.substring(start, end))
return list
}
/**
* Mark that a request is varied on a header field.
*
* @param {Object} res
* @param {String|Array} field
* @public
*/
function vary (res, field) {
if (!res || !res.getHeader || !res.setHeader) {
// quack quack
throw new TypeError('res argument is required')
}
// get existing header
var val = res.getHeader('Vary') || ''
var header = Array.isArray(val)
? val.join(', ')
: String(val)
// set new header
if ((val = append(header, field))) {
res.setHeader('Vary', val)
}
}
|
