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/*!
* type-is
* Copyright(c) 2014 Jonathan Ong
* Copyright(c) 2014-2015 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module dependencies.
* @private
*/
var typer = require('media-typer')
var mime = require('mime-types')
/**
* Module exports.
* @public
*/
module.exports = typeofrequest
module.exports.is = typeis
module.exports.hasBody = hasbody
module.exports.normalize = normalize
module.exports.match = mimeMatch
/**
* Compare a `value` content-type with `types`.
* Each `type` can be an extension like `html`,
* a special shortcut like `multipart` or `urlencoded`,
* or a mime type.
*
* If no types match, `false` is returned.
* Otherwise, the first `type` that matches is returned.
*
* @param {String} value
* @param {Array} types
* @public
*/
function typeis (value, types_) {
var i
var types = types_
// remove parameters and normalize
var val = tryNormalizeType(value)
// no type or invalid
if (!val) {
return false
}
// support flattened arguments
if (types && !Array.isArray(types)) {
types = new Array(arguments.length - 1)
for (i = 0; i < types.length; i++) {
types[i] = arguments[i + 1]
}
}
// no types, return the content type
if (!types || !types.length) {
return val
}
var type
for (i = 0; i < types.length; i++) {
if (mimeMatch(normalize(type = types[i]), val)) {
return type[0] === '+' || type.indexOf('*') !== -1
? val
: type
}
}
// no matches
return false
}
/**
* Check if a request has a request body.
* A request with a body __must__ either have `transfer-encoding`
* or `content-length` headers set.
* http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.3
*
* @param {Object} request
* @return {Boolean}
* @public
*/
function hasbody (req) {
return req.headers['transfer-encoding'] !== undefined ||
!isNaN(req.headers['content-length'])
}
/**
* Check if the incoming request contains the "Content-Type"
* header field, and it contains any of the give mime `type`s.
* If there is no request body, `null` is returned.
* If there is no content type, `false` is returned.
* Otherwise, it returns the first `type` that matches.
*
* Examples:
*
* // With Content-Type: text/html; charset=utf-8
* this.is('html'); // => 'html'
* this.is('text/html'); // => 'text/html'
* this.is('text/*', 'application/json'); // => 'text/html'
*
* // When Content-Type is application/json
* this.is('json', 'urlencoded'); // => 'json'
* this.is('application/json'); // => 'application/json'
* this.is('html', 'application/*'); // => 'application/json'
*
* this.is('html'); // => false
*
* @param {String|Array} types...
* @return {String|false|null}
* @public
*/
function typeofrequest (req, types_) {
var types = types_
// no body
if (!hasbody(req)) {
return null
}
// support flattened arguments
if (arguments.length > 2) {
types = new Array(arguments.length - 1)
for (var i = 0; i < types.length; i++) {
types[i] = arguments[i + 1]
}
}
// request content type
var value = req.headers['content-type']
return typeis(value, types)
}
/**
* Normalize a mime type.
* If it's a shorthand, expand it to a valid mime type.
*
* In general, you probably want:
*
* var type = is(req, ['urlencoded', 'json', 'multipart']);
*
* Then use the appropriate body parsers.
* These three are the most common request body types
* and are thus ensured to work.
*
* @param {String} type
* @private
*/
function normalize (type) {
if (typeof type !== 'string') {
// invalid type
return false
}
switch (type) {
case 'urlencoded':
return 'application/x-www-form-urlencoded'
case 'multipart':
return 'multipart/*'
}
if (type[0] === '+') {
// "+json" -> "*/*+json" expando
return '*/*' + type
}
return type.indexOf('/') === -1
? mime.lookup(type)
: type
}
/**
* Check if `expected` mime type
* matches `actual` mime type with
* wildcard and +suffix support.
*
* @param {String} expected
* @param {String} actual
* @return {Boolean}
* @private
*/
function mimeMatch (expected, actual) {
// invalid type
if (expected === false) {
return false
}
// split types
var actualParts = actual.split('/')
var expectedParts = expected.split('/')
// invalid format
if (actualParts.length !== 2 || expectedParts.length !== 2) {
return false
}
// validate type
if (expectedParts[0] !== '*' && expectedParts[0] !== actualParts[0]) {
return false
}
// validate suffix wildcard
if (expectedParts[1].substr(0, 2) === '*+') {
return expectedParts[1].length <= actualParts[1].length + 1 &&
expectedParts[1].substr(1) === actualParts[1].substr(1 - expectedParts[1].length)
}
// validate subtype
if (expectedParts[1] !== '*' && expectedParts[1] !== actualParts[1]) {
return false
}
return true
}
/**
* Normalize a type and remove parameters.
*
* @param {string} value
* @return {string}
* @private
*/
function normalizeType (value) {
// parse the type
var type = typer.parse(value)
// remove the parameters
type.parameters = undefined
// reformat it
return typer.format(type)
}
/**
* Try to normalize a type and remove parameters.
*
* @param {string} value
* @return {string}
* @private
*/
function tryNormalizeType (value) {
if (!value) {
return null
}
try {
return normalizeType(value)
} catch (err) {
return null
}
}