Repositorio del curso CCOM4030 el semestre B91 del proyecto kilometro0

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