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
|
module.exports = preferredMediaTypes;
preferredMediaTypes.preferredMediaTypes = preferredMediaTypes;
function parseAccept(accept) {
var accepts = accept.split(',');
for (var i = 0, j = 0; i < accepts.length; i++) {
var mediaType = parseMediaType(accepts[i].trim(), i);
if (mediaType) {
accepts[j++] = mediaType;
}
}
// trim accepts
accepts.length = j;
return accepts;
};
function parseMediaType(s, i) {
var match = s.match(/\s*(\S+?)\/([^;\s]+)\s*(?:;(.*))?/);
if (!match) return null;
var type = match[1],
subtype = match[2],
full = "" + type + "/" + subtype,
params = {},
q = 1;
if (match[3]) {
params = match[3].split(';').map(function(s) {
return s.trim().split('=');
}).reduce(function (set, p) {
set[p[0]] = p[1];
return set
}, params);
if (params.q != null) {
q = parseFloat(params.q);
delete params.q;
}
}
return {
type: type,
subtype: subtype,
params: params,
q: q,
i: i,
full: full
};
}
function getMediaTypePriority(type, accepted, index) {
var priority = {o: -1, q: 0, s: 0};
for (var i = 0; i < accepted.length; i++) {
var spec = specify(type, accepted[i], index);
if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
priority = spec;
}
}
return priority;
}
function specify(type, spec, index) {
var p = parseMediaType(type);
var s = 0;
if (!p) {
return null;
}
if(spec.type.toLowerCase() == p.type.toLowerCase()) {
s |= 4
} else if(spec.type != '*') {
return null;
}
if(spec.subtype.toLowerCase() == p.subtype.toLowerCase()) {
s |= 2
} else if(spec.subtype != '*') {
return null;
}
var keys = Object.keys(spec.params);
if (keys.length > 0) {
if (keys.every(function (k) {
return spec.params[k] == '*' || (spec.params[k] || '').toLowerCase() == (p.params[k] || '').toLowerCase();
})) {
s |= 1
} else {
return null
}
}
return {
i: index,
o: spec.i,
q: spec.q,
s: s,
}
}
function preferredMediaTypes(accept, provided) {
// RFC 2616 sec 14.2: no header = */*
var accepts = parseAccept(accept === undefined ? '*/*' : accept || '');
if (!provided) {
// sorted list of all types
return accepts.filter(isQuality).sort(compareSpecs).map(function getType(spec) {
return spec.full;
});
}
var priorities = provided.map(function getPriority(type, index) {
return getMediaTypePriority(type, accepts, index);
});
// sorted list of accepted types
return priorities.filter(isQuality).sort(compareSpecs).map(function getType(priority) {
return provided[priorities.indexOf(priority)];
});
}
function compareSpecs(a, b) {
return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
}
function isQuality(spec) {
return spec.q > 0;
}
|
