body-parser
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Node.js body parsing middleware.
This does not handle multipart bodies, due to their complex and typically
large nature. For multipart bodies, you may be interested in the following
modules:
This module provides the following parsers:
Other body parsers you might be interested in:
Installation
$ npm install body-parser
API
var bodyParser = require('body-parser')
The bodyParser
object exposes various factories to create middlewares. All
middlewares will populate the req.body
property with the parsed body or
provide an error to the callback. The various errors are described in the
errors section.
bodyParser.json(options)
Returns middleware that only parses json
. This parser accepts any Unicode
encoding of the body and supports automatic inflation of gzip
and deflate
encodings.
A new body
object containing the parsed data is populated on the request
object after the middleware (i.e. req.body
).
Options
The json
function takes an option options
object that may contain any of
the following keys:
inflate
When set to true
, then deflated (compressed) bodies will be inflated; when
false
, deflated bodies are rejected. Defaults to true
.
limit
Controls the maximum request body size. If this is a number, then the value
specifies the number of bytes; if it is a string, the value is passed to the
bytes library for parsing. Defaults
to '100kb'
.
reviver
The reviver
option is passed directly to JSON.parse
as the second
argument. You can find more information on this argument
in the MDN documentation about JSON.parse.
strict
When set to true
, will only accept arrays and objects; when false
will
accept anything JSON.parse
accepts. Defaults to true
.
type
The type
option is used to determine what media type the middleware will
parse. This option can be a function or a string. If a string, type
option
is passed directly to the type-is
library and this can be an extension name (like json
), a mime type (like
application/json
), or a mime time with a wildcard (like */*
or */json
).
If a function, the type
option is called as fn(req)
and the request is
parsed if it returns a truthy value. Defaults to json
.
verify
The verify
option, if supplied, is called as verify(req, res, buf, encoding)
,
where buf
is a Buffer
of the raw request body and encoding
is the
encoding of the request. The parsing can be aborted by throwing an error.
bodyParser.raw(options)
Returns middleware that parses all bodies as a Buffer
. This parser
supports automatic inflation of gzip
and deflate
encodings.
A new body
object containing the parsed data is populated on the request
object after the middleware (i.e. req.body
). This will be a Buffer
object
of the body.
Options
The raw
function takes an option options
object that may contain any of
the following keys:
inflate
When set to true
, then deflated (compressed) bodies will be inflated; when
false
, deflated bodies are rejected. Defaults to true
.
limit
Controls the maximum request body size. If this is a number, then the value
specifies the number of bytes; if it is a string, the value is passed to the
bytes library for parsing. Defaults
to '100kb'
.
type
The type
option is used to determine what media type the middleware will
parse. This option can be a function or a string. If a string, type
option
is passed directly to the type-is
library and this can be an extension name (like bin
), a mime type (like
application/octet-stream
), or a mime time with a wildcard (like */*
or
application/*
). If a function, the type
option is called as fn(req)
and the request is parsed if it returns a truthy value. Defaults to
application/octet-stream
.
verify
The verify
option, if supplied, is called as verify(req, res, buf, encoding)
,
where buf
is a Buffer
of the raw request body and encoding
is the
encoding of the request. The parsing can be aborted by throwing an error.
bodyParser.text(options)
Returns middleware that parses all bodies as a string. This parser supports
automatic inflation of gzip
and deflate
encodings.
A new body
string containing the parsed data is populated on the request
object after the middleware (i.e. req.body
). This will be a string of the
body.
Options
The text
function takes an option options
object that may contain any of
the following keys:
defaultCharset
Specify the default character set for the text content if the charset is not
specified in the Content-Type
header of the request. Defaults to utf-8
.
inflate
When set to true
, then deflated (compressed) bodies will be inflated; when
false
, deflated bodies are rejected. Defaults to true
.
limit
Controls the maximum request body size. If this is a number, then the value
specifies the number of bytes; if it is a string, the value is passed to the
bytes library for parsing. Defaults
to '100kb'
.
type
The type
option is used to determine what media type the middleware will
parse. This option can be a function or a string. If a string, type
option
is passed directly to the type-is
library and this can be an extension name (like txt
), a mime type (like
text/plain
), or a mime time with a wildcard (like */*
or text/*
).
If a function, the type
option is called as fn(req)
and the request is
parsed if it returns a truthy value. Defaults to text/plain
.
verify
The verify
option, if supplied, is called as verify(req, res, buf, encoding)
,
where buf
is a Buffer
of the raw request body and encoding
is the
encoding of the request. The parsing can be aborted by throwing an error.
bodyParser.urlencoded(options)
Returns middleware that only parses urlencoded
bodies. This parser accepts
only UTF-8 encoding of the body and supports automatic inflation of gzip
and deflate
encodings.
A new body
object containing the parsed data is populated on the request
object after the middleware (i.e. req.body
). This object will contain
key-value pairs, where the value can be a string or array (when extended
is
false
), or any type (when extended
is true
).
Options
The urlencoded
function takes an option options
object that may contain
any of the following keys:
extended
The extended
option allows to choose between parsing the URL-encoded data
with the querystring
library (when false
) or the qs
library (when
true
). The "extended" syntax allows for rich objects and arrays to be
encoded into the URL-encoded format, allowing for a JSON-like experience
with URL-encoded. For more information, please
see the qs library.
Defaults to true
, but using the default has been deprecated. Please
research into the difference between qs
and querystring
and choose the
appropriate setting.
inflate
When set to true
, then deflated (compressed) bodies will be inflated; when
false
, deflated bodies are rejected. Defaults to true
.
limit
Controls the maximum request body size. If this is a number, then the value
specifies the number of bytes; if it is a string, the value is passed to the
bytes library for parsing. Defaults
to '100kb'
.
parameterLimit
The parameterLimit
option controls the maximum number of parameters that
are allowed in the URL-encoded data. If a request contains more parameters
than this value, a 413 will be returned to the client. Defaults to 1000
.
type
The type
option is used to determine what media type the middleware will
parse. This option can be a function or a string. If a string, type
option
is passed directly to the type-is
library and this can be an extension name (like urlencoded
), a mime type (like
application/x-www-form-urlencoded
), or a mime time with a wildcard (like
*/x-www-form-urlencoded
). If a function, the type
option is called as
fn(req)
and the request is parsed if it returns a truthy value. Defaults
to urlencoded
.
verify
The verify
option, if supplied, is called as verify(req, res, buf, encoding)
,
where buf
is a Buffer
of the raw request body and encoding
is the
encoding of the request. The parsing can be aborted by throwing an error.
Errors
The middlewares provided by this module create errors depending on the error
condition during parsing. The errors will typically have a status
property
that contains the suggested HTTP response code.
The following are the common errors emitted, though any error can come through
for various reasons.
content encoding unsupported
This error will occur when the request had a Content-Encoding
header that
contained an encoding but the "inflation" option was set to false
. The
status
property is set to 415
.
request aborted
This error will occur when the request is aborted by the client before reading
the body has finished. The received
property will be set to the number of
bytes received before the request was aborted and the expected
property is
set to the number of expected bytes. The status
property is set to 400
.
request entity too large
This error will occur when the request body's size is larger than the "limit"
option. The limit
property will be set to the byte limit and the length
property will be set to the request body's length. The status
property is
set to 413
.
request size did not match content length
This error will occur when the request's length did not match the length from
the Content-Lentgh
header. This typically occurs when the requst is malformed,
typically when the Content-Length
header was calculated based on characters
instead of bytes. The status
property is set to 400
.
stream encoding should not be set
This error will occur when something called the req.setEncoding
method prior
to this middleware. This module operates directly on bytes only and you cannot
call req.setEncoding
when using this module. The status
property is set to
500
.
unsupported charset "BOGUS"
This error will occur when the request had a charset parameter in the
Content-Type
header, but the iconv-lite
module does not support it OR the
parser does not support it. The charset is contained in the message as well
as in the charset
property. The status
property is set to 415
.
unsupported content encoding "bogus"
This error will occur when the request had a Content-Encoding
header that
contained an unsupported encoding. The encoding is contained in the message
as well as in the encoding
property. The status
property is set to 415
.
Examples
express/connect top-level generic
This example demonstrates adding a generic JSON and URL-encoded parser as a
top-level middleware, which will parse the bodies of all incoming requests.
This is the simplest setup.
var express = require('express')
var bodyParser = require('body-parser')
var app = express()
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())
app.use(function (req, res) {
res.setHeader('Content-Type', 'text/plain')
res.write('you posted:\n')
res.end(JSON.stringify(req.body, null, 2))
})
express route-specific
This example demonstrates adding body parsers specifically to the routes that
need them. In general, this is the most recommend way to use body-parser with
express.
var express = require('express')
var bodyParser = require('body-parser')
var app = express()
var jsonParser = bodyParser.json()
var urlencodedParser = bodyParser.urlencoded({ extended: false })
app.post('/login', urlencodedParser, function (req, res) {
if (!req.body) return res.sendStatus(400)
res.send('welcome, ' + req.body.username)
})
app.post('/api/users', jsonParser, function (req, res) {
if (!req.body) return res.sendStatus(400)
})
change content-type for parsers
All the parsers accept a type
option which allows you to change the
Content-Type
that the middleware will parse.
app.use(bodyParser.json({ type: 'application/*+json' }))
app.use(bodyParser.raw({ type: 'application/vnd.custom-type' }))
app.use(bodyParser.text({ type: 'text/html' }))
License
MIT