147 lines
4.1 KiB
Markdown
147 lines
4.1 KiB
Markdown
# type-is
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[![NPM Version][npm-image]][npm-url]
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[![NPM Downloads][downloads-image]][downloads-url]
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[![Node.js Version][node-version-image]][node-version-url]
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[![Build Status][travis-image]][travis-url]
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[![Test Coverage][coveralls-image]][coveralls-url]
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Infer the content-type of a request.
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### Install
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This is a [Node.js](https://nodejs.org/en/) module available through the
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[npm registry](https://www.npmjs.com/). Installation is done using the
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[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
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```sh
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$ npm install type-is
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```
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## API
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```js
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var http = require('http')
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var typeis = require('type-is')
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http.createServer(function (req, res) {
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var istext = typeis(req, ['text/*'])
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res.end('you ' + (istext ? 'sent' : 'did not send') + ' me text')
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})
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```
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### type = typeis(request, types)
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`request` is the node HTTP request. `types` is an array of types.
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<!-- eslint-disable no-undef -->
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```js
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// req.headers.content-type = 'application/json'
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typeis(req, ['json']) // 'json'
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typeis(req, ['html', 'json']) // 'json'
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typeis(req, ['application/*']) // 'application/json'
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typeis(req, ['application/json']) // 'application/json'
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typeis(req, ['html']) // false
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```
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### typeis.hasBody(request)
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Returns a Boolean if the given `request` has a body, regardless of the
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`Content-Type` header.
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Having a body has no relation to how large the body is (it may be 0 bytes).
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This is similar to how file existence works. If a body does exist, then this
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indicates that there is data to read from the Node.js request stream.
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<!-- eslint-disable no-undef -->
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```js
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if (typeis.hasBody(req)) {
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// read the body, since there is one
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req.on('data', function (chunk) {
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// ...
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})
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}
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```
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### type = typeis.is(mediaType, types)
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`mediaType` is the [media type](https://tools.ietf.org/html/rfc6838) string. `types` is an array of types.
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<!-- eslint-disable no-undef -->
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```js
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var mediaType = 'application/json'
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typeis.is(mediaType, ['json']) // 'json'
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typeis.is(mediaType, ['html', 'json']) // 'json'
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typeis.is(mediaType, ['application/*']) // 'application/json'
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typeis.is(mediaType, ['application/json']) // 'application/json'
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typeis.is(mediaType, ['html']) // false
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```
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### Each type can be:
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- An extension name such as `json`. This name will be returned if matched.
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- A mime type such as `application/json`.
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- A mime type with a wildcard such as `*/*` or `*/json` or `application/*`. The full mime type will be returned if matched.
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- A suffix such as `+json`. This can be combined with a wildcard such as `*/vnd+json` or `application/*+json`. The full mime type will be returned if matched.
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`false` will be returned if no type matches or the content type is invalid.
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`null` will be returned if the request does not have a body.
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## Examples
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### Example body parser
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```js
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var express = require('express')
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var typeis = require('type-is')
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var app = express()
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app.use(function bodyParser (req, res, next) {
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if (!typeis.hasBody(req)) {
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return next()
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}
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switch (typeis(req, ['urlencoded', 'json', 'multipart'])) {
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case 'urlencoded':
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// parse urlencoded body
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throw new Error('implement urlencoded body parsing')
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case 'json':
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// parse json body
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throw new Error('implement json body parsing')
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case 'multipart':
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// parse multipart body
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throw new Error('implement multipart body parsing')
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default:
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// 415 error code
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res.statusCode = 415
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res.end()
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break
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}
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})
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```
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## License
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[MIT](LICENSE)
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[npm-image]: https://img.shields.io/npm/v/type-is.svg
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[npm-url]: https://npmjs.org/package/type-is
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[node-version-image]: https://img.shields.io/node/v/type-is.svg
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[node-version-url]: https://nodejs.org/en/download/
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[travis-image]: https://img.shields.io/travis/jshttp/type-is/master.svg
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[travis-url]: https://travis-ci.org/jshttp/type-is
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[coveralls-image]: https://img.shields.io/coveralls/jshttp/type-is/master.svg
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[coveralls-url]: https://coveralls.io/r/jshttp/type-is?branch=master
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[downloads-image]: https://img.shields.io/npm/dm/type-is.svg
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[downloads-url]: https://npmjs.org/package/type-is
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