150 lines
2.9 KiB
JavaScript
150 lines
2.9 KiB
JavaScript
/*!
|
|
* 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)
|
|
}
|
|
}
|