Infer the content-type of a request.
This is a Node.js module available through the npm registry. Installation is done using the npm install
command:
$ npm install type-is
var http = require('http') var typeis = require('type-is') http.createServer(function (req, res) { var istext = typeis(req, ['text/*']) res.end('you ' + (istext ? 'sent' : 'did not send') + ' me text') })
Checks if the request
is one of the types
. If the request has no body, even if there is a Content-Type
header, then null
is returned. If the Content-Type
header is invalid or does not matches any of the types
, then false
is returned. Otherwise, a string of the type that matched is returned.
The request
argument is expected to be a Node.js HTTP request. The types
argument is an array of type strings.
Each type in the types
array can be one of the following:
json
. This name will be returned if matched.application/json
.*/*
or */json
or application/*
. The full mime type will be returned if matched.+json
. This can be combined with a wildcard such as */vnd+json
or application/*+json
. The full mime type will be returned if matched.Some examples to illustrate the inputs and returned value:
// req.headers.content-type = 'application/json' typeis(req, ['json']) // => 'json' typeis(req, ['html', 'json']) // => 'json' typeis(req, ['application/*']) // => 'application/json' typeis(req, ['application/json']) // => 'application/json' typeis(req, ['html']) // => false
Returns a Boolean if the given request
has a body, regardless of the Content-Type
header.
Having a body has no relation to how large the body is (it may be 0 bytes). This is similar to how file existence works. If a body does exist, then this indicates that there is data to read from the Node.js request stream.
if (typeis.hasBody(req)) { // read the body, since there is one req.on('data', function (chunk) { // ... }) }
Checks if the mediaType
is one of the types
. If the mediaType
is invalid or does not matches any of the types
, then false
is returned. Otherwise, a string of the type that matched is returned.
The mediaType
argument is expected to be a media type string. The types
argument is an array of type strings.
Each type in the types
array can be one of the following:
json
. This name will be returned if matched.application/json
.*/*
or */json
or application/*
. The full mime type will be returned if matched.+json
. This can be combined with a wildcard such as */vnd+json
or application/*+json
. The full mime type will be returned if matched.Some examples to illustrate the inputs and returned value:
var mediaType = 'application/json' typeis.is(mediaType, ['json']) // => 'json' typeis.is(mediaType, ['html', 'json']) // => 'json' typeis.is(mediaType, ['application/*']) // => 'application/json' typeis.is(mediaType, ['application/json']) // => 'application/json' typeis.is(mediaType, ['html']) // => false
var express = require('express') var typeis = require('type-is') var app = express() app.use(function bodyParser (req, res, next) { if (!typeis.hasBody(req)) { return next() } switch (typeis(req, ['urlencoded', 'json', 'multipart'])) { case 'urlencoded': // parse urlencoded body throw new Error('implement urlencoded body parsing') case 'json': // parse json body throw new Error('implement json body parsing') case 'multipart': // parse multipart body throw new Error('implement multipart body parsing') default: // 415 error code res.statusCode = 415 res.end() break } })