[6a3a178] | 1 | # type-is
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| 2 |
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| 3 | [![NPM Version][npm-version-image]][npm-url]
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| 4 | [![NPM Downloads][npm-downloads-image]][npm-url]
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| 5 | [![Node.js Version][node-version-image]][node-version-url]
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| 6 | [![Build Status][travis-image]][travis-url]
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| 7 | [![Test Coverage][coveralls-image]][coveralls-url]
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| 8 |
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| 9 | Infer the content-type of a request.
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| 10 |
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| 11 | ### Install
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| 12 |
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| 13 | This is a [Node.js](https://nodejs.org/en/) module available through the
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| 14 | [npm registry](https://www.npmjs.com/). Installation is done using the
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| 15 | [`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
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| 16 |
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| 17 | ```sh
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| 18 | $ npm install type-is
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| 19 | ```
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| 20 |
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| 21 | ## API
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| 22 |
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| 23 | ```js
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| 24 | var http = require('http')
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| 25 | var typeis = require('type-is')
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| 26 |
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| 27 | http.createServer(function (req, res) {
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| 28 | var istext = typeis(req, ['text/*'])
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| 29 | res.end('you ' + (istext ? 'sent' : 'did not send') + ' me text')
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| 30 | })
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| 31 | ```
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| 32 |
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| 33 | ### typeis(request, types)
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| 34 |
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| 35 | Checks if the `request` is one of the `types`. If the request has no body,
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| 36 | even if there is a `Content-Type` header, then `null` is returned. If the
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| 37 | `Content-Type` header is invalid or does not matches any of the `types`, then
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| 38 | `false` is returned. Otherwise, a string of the type that matched is returned.
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| 39 |
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| 40 | The `request` argument is expected to be a Node.js HTTP request. The `types`
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| 41 | argument is an array of type strings.
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| 42 |
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| 43 | Each type in the `types` array can be one of the following:
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| 44 |
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| 45 | - A file extension name such as `json`. This name will be returned if matched.
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| 46 | - A mime type such as `application/json`.
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| 47 | - A mime type with a wildcard such as `*/*` or `*/json` or `application/*`.
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| 48 | The full mime type will be returned if matched.
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| 49 | - A suffix such as `+json`. This can be combined with a wildcard such as
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| 50 | `*/vnd+json` or `application/*+json`. The full mime type will be returned
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| 51 | if matched.
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| 52 |
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| 53 | Some examples to illustrate the inputs and returned value:
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| 54 |
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| 55 | <!-- eslint-disable no-undef -->
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| 56 |
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| 57 | ```js
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| 58 | // req.headers.content-type = 'application/json'
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| 59 |
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| 60 | typeis(req, ['json']) // => 'json'
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| 61 | typeis(req, ['html', 'json']) // => 'json'
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| 62 | typeis(req, ['application/*']) // => 'application/json'
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| 63 | typeis(req, ['application/json']) // => 'application/json'
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| 64 |
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| 65 | typeis(req, ['html']) // => false
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| 66 | ```
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| 67 |
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| 68 | ### typeis.hasBody(request)
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| 69 |
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| 70 | Returns a Boolean if the given `request` has a body, regardless of the
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| 71 | `Content-Type` header.
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| 72 |
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| 73 | Having a body has no relation to how large the body is (it may be 0 bytes).
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| 74 | This is similar to how file existence works. If a body does exist, then this
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| 75 | indicates that there is data to read from the Node.js request stream.
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| 76 |
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| 77 | <!-- eslint-disable no-undef -->
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| 78 |
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| 79 | ```js
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| 80 | if (typeis.hasBody(req)) {
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| 81 | // read the body, since there is one
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| 82 |
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| 83 | req.on('data', function (chunk) {
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| 84 | // ...
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| 85 | })
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| 86 | }
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| 87 | ```
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| 88 |
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| 89 | ### typeis.is(mediaType, types)
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| 90 |
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| 91 | Checks if the `mediaType` is one of the `types`. If the `mediaType` is invalid
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| 92 | or does not matches any of the `types`, then `false` is returned. Otherwise, a
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| 93 | string of the type that matched is returned.
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| 94 |
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| 95 | The `mediaType` argument is expected to be a
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| 96 | [media type](https://tools.ietf.org/html/rfc6838) string. The `types` argument
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| 97 | is an array of type strings.
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| 98 |
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| 99 | Each type in the `types` array can be one of the following:
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| 100 |
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| 101 | - A file extension name such as `json`. This name will be returned if matched.
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| 102 | - A mime type such as `application/json`.
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| 103 | - A mime type with a wildcard such as `*/*` or `*/json` or `application/*`.
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| 104 | The full mime type will be returned if matched.
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| 105 | - A suffix such as `+json`. This can be combined with a wildcard such as
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| 106 | `*/vnd+json` or `application/*+json`. The full mime type will be returned
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| 107 | if matched.
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| 108 |
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| 109 | Some examples to illustrate the inputs and returned value:
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| 110 |
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| 111 | <!-- eslint-disable no-undef -->
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| 112 |
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| 113 | ```js
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| 114 | var mediaType = 'application/json'
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| 115 |
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| 116 | typeis.is(mediaType, ['json']) // => 'json'
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| 117 | typeis.is(mediaType, ['html', 'json']) // => 'json'
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| 118 | typeis.is(mediaType, ['application/*']) // => 'application/json'
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| 119 | typeis.is(mediaType, ['application/json']) // => 'application/json'
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| 120 |
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| 121 | typeis.is(mediaType, ['html']) // => false
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| 122 | ```
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| 123 |
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| 124 | ## Examples
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| 125 |
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| 126 | ### Example body parser
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| 127 |
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| 128 | ```js
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| 129 | var express = require('express')
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| 130 | var typeis = require('type-is')
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| 131 |
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| 132 | var app = express()
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| 133 |
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| 134 | app.use(function bodyParser (req, res, next) {
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| 135 | if (!typeis.hasBody(req)) {
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| 136 | return next()
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| 137 | }
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| 138 |
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| 139 | switch (typeis(req, ['urlencoded', 'json', 'multipart'])) {
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| 140 | case 'urlencoded':
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| 141 | // parse urlencoded body
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| 142 | throw new Error('implement urlencoded body parsing')
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| 143 | case 'json':
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| 144 | // parse json body
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| 145 | throw new Error('implement json body parsing')
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| 146 | case 'multipart':
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| 147 | // parse multipart body
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| 148 | throw new Error('implement multipart body parsing')
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| 149 | default:
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| 150 | // 415 error code
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| 151 | res.statusCode = 415
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| 152 | res.end()
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| 153 | break
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| 154 | }
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| 155 | })
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| 156 | ```
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| 157 |
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| 158 | ## License
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| 159 |
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| 160 | [MIT](LICENSE)
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| 161 |
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| 162 | [coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/type-is/master
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| 163 | [coveralls-url]: https://coveralls.io/r/jshttp/type-is?branch=master
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| 164 | [node-version-image]: https://badgen.net/npm/node/type-is
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| 165 | [node-version-url]: https://nodejs.org/en/download
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| 166 | [npm-downloads-image]: https://badgen.net/npm/dm/type-is
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| 167 | [npm-url]: https://npmjs.org/package/type-is
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| 168 | [npm-version-image]: https://badgen.net/npm/v/type-is
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| 169 | [travis-image]: https://badgen.net/travis/jshttp/type-is/master
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| 170 | [travis-url]: https://travis-ci.org/jshttp/type-is
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