Infer the content-type of a request.
npm install xprezzo-typeisInfer the content-type of a request.
This is a Node.js module available through the
npm registry. Installation is done using thenpm install command:
``sh`
$ npm install xprezzo-typeis
`js
var http = require('http')
var typeis = require('xprezzo-typeis')
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,Content-Type
even if there is a header, then null is returned. If theContent-Type header is invalid or does not matches any of the types, thenfalse 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:
- A file extension name such as json. This name will be returned if matched.application/json
- A mime type such as ./
- A mime type with a wildcard such as or /json or application/.+json
The full mime type will be returned if matched.
- A suffix such as . 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:
`js
// 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 theContent-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.
`js
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 invalidtypes
or does not matches any of the , then false is returned. Otherwise, a
string of the type that matched is returned.
The mediaType argument is expected to be atypes
media type string. The argument
is an array of type strings.
Each type in the types array can be one of the following:
- A file extension name such as json. This name will be returned if matched.application/json
- A mime type such as ./
- A mime type with a wildcard such as or /json or application/.+json
The full mime type will be returned if matched.
- A suffix such as . 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:
`js
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
`
`js
var express = require('express')
var typeis = require('xprezzo-typeis')
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
}
})
``
Xprezzo and related projects are maintained by Cloudgen Wong.