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var typer = require('media-typer')
var mime = require('mime-types')
module.exports = typeofrequest;
typeofrequest.is = typeis;
typeofrequest.hasBody = hasbody;
typeofrequest.normalize = normalize;
typeofrequest.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
* @return String
*/
function typeis(value, types_) {
var i
var types = types_
// remove parameters and normalize
var val = typenormalize(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('*')
? 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}
* @api public
*/
function hasbody(req) {
var headers = req.headers;
if ('transfer-encoding' in headers) return true;
return !isNaN(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}
* @api 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
* @api private
*/
function normalize(type) {
switch (type) {
case 'urlencoded': return 'application/x-www-form-urlencoded';
case 'multipart':
type = 'multipart/*';
break;
}
return type[0] === '+' || ~type.indexOf('/')
? type
: mime.lookup(type)
}
/**
* Check if `exected` mime type
* matches `actual` mime type with
* wildcard and +suffix support.
*
* @param {String} expected
* @param {String} actual
* @return {Boolean}
* @api private
*/
function mimeMatch(expected, actual) {
// invalid type
if (expected === false) {
return false
}
// exact match
if (expected === actual) {
return true
}
actual = actual.split('/');
if (expected[0] === '+') {
// support +suffix
return Boolean(actual[1])
&& expected.length <= actual[1].length
&& expected === actual[1].substr(0 - expected.length)
}
if (!~expected.indexOf('*')) return false;
expected = expected.split('/');
if (expected[0] === '*') {
// support */yyy
return expected[1] === actual[1]
}
if (expected[1] === '*') {
// support xxx/*
return expected[0] === actual[0]
}
if (expected[1][0] === '*' && expected[1][1] === '+') {
// support xxx/*+zzz
return expected[0] === actual[0]
&& expected[1].length <= actual[1].length + 1
&& expected[1].substr(1) === actual[1].substr(1 - expected[1].length)
}
return false
}
/**
* Normalize a type and remove parameters.
*
* @param {string} value
* @return {string}
* @api private
*/
function typenormalize(value) {
try {
var type = typer.parse(value)
delete type.parameters
return typer.format(type)
} catch (err) {
return null
}
}
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