Xprezzo json parser middleware
npm install xprezzo-json-parserA middleware that only parses json and only looks at requests where
the Content-Type header matches the type option. This parser accepts any
Unicode encoding of the body and supports automatic inflation of gzip anddeflate encodings.
A new body object containing the parsed data is populated on the request
object after the middleware (i.e. req.body).
``sh`
$ npm install xprezzo-json-parser
`js`
var JsonParser = require('xprezzo-json-parser')
The JsonParser object exposes various factories to create middlewares. Allreq.body
middlewares will populate the property with the parsed body whenContent-Type
the request header matches the type option, or an empty{}
object () if there was no body to parse, the Content-Type was not matched,
or an error occurred.
The various errors returned by this module are described in the
errors section.
#### Options
The json function takes an optional options object that may contain any of
the following keys:
##### inflate
When set to true, then deflated (compressed) bodies will be inflated; whenfalse, 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 willJSON.parse
accept anything accepts. Defaults to true.
##### type
The type option is used to determine what media type the middleware willtype
parse. This option can be a string, array of strings, or a function. If not a
function, option is passed directly to thejson
type-is library and this can
be an extension name (like ), a mime type (like application/json), or/
a mime type with a wildcard (like or */json). If a function, the typefn(req)
option is called as and the request is parsed if it returns a truthyapplication/json
value. Defaults to .
##### verify
The verify option, if supplied, is called as verify(req, res, buf, encoding),buf
where 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.
The middlewares provided by this module create errors using the
xprezzo-http-errors module. The errors
will typically have a status/statusCode property that contains the suggestedexpose
HTTP response code, an property to determine if the message propertytype
should be displayed to the client, a property to determine the type ofmessage
error without matching against the , and a body property containing
the read body, if available.
The following are the common errors created, though any error can come through
for various reasons.
This error will occur when the request had a Content-Encoding header thatfalse
contained an encoding but the "inflation" option was set to . Thestatus property is set to 415, the type property is set to'encoding.unsupported', and the charset property will be set to the
encoding that is unsupported.
This error will occur when the request contained an entity that could not be
parsed by the middleware. The status property is set to 400, the type'entity.parse.failed'
property is set to , and the body property is set to
the entity value that failed parsing.
This error will occur when the request contained an entity that could not be
failed verification by the defined verify option. The status property is403
set to , the type property is set to 'entity.verify.failed', and thebody property is set to the entity value that failed verification.
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 ofexpected
bytes received before the request was aborted and the property isstatus
set to the number of expected bytes. The property is set to 400type
and property is set to 'request.aborted'.
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 lengthstatus
property will be set to the request body's length. The property is413
set to and the type property is set to 'entity.too.large'.
This error will occur when the request's length did not match the length from
the Content-Length header. This typically occurs when the request is malformed,Content-Length
typically when the header was calculated based on charactersstatus
instead of bytes. The property is set to 400 and the type property'request.size.invalid'
is set to .
This error will occur when something called the req.setEncoding method priorreq.setEncoding
to this middleware. This module operates directly on bytes only and you cannot
call when using this module. The status property is set to500 and the type property is set to 'stream.encoding.set'.
This error will occur when the content of the request exceeds the configured
parameterLimit for the urlencoded parser. The status property is set to413 and the type property is set to 'parameters.too.many'.
This error will occur when the request had a charset parameter in the
Content-Type header, but the xprezzo-iconv-lite module does not support it OR thecharset
parser does not support it. The charset is contained in the message as well
as in the property. The status property is set to 415, thetype property is set to 'charset.unsupported', and the charset property
is set to the charset that is unsupported.
This error will occur when the request had a Content-Encoding header thatencoding
contained an unsupported encoding. The encoding is contained in the message
as well as in the property. The status property is set to 415,type
the property is set to 'encoding.unsupported', and the encoding
property is set to the encoding that is unsupported.
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.
`js
var Xprezzo = require('xprezzo')
var JsonParser = require('xprezzo-json-parser')
var app = Xprezzo()
// parse application/json
app.use(JsonParser())
app.use(function (req, res) {
res.setHeader('Content-Type', 'text/plain')
res.write('you posted:\n')
res.end(JSON.stringify(req.body, null, 2))
})
`
This example demonstrates adding body parsers specifically to the routes that
need them. In general, this is the most recommended way to use body-parser with
Express.
`js
var Xprezzo = require('xprezzo')
var JsonParser = require('xprezzo-json-parser')
var app = Xprezzo()
// POST /api/users gets JSON bodies
app.post('/api/users', JsonParser, function (req, res) {
// create user in req.body
})
`
All the parsers accept a type option which allows you to change theContent-Type that the middleware will parse.
`js
var Xprezzo = require('xprezzo')
var JsonParser = require('xprezzo-json-parser')
var app = Xprezzo()
// parse various different custom JSON types as JSON
app.use(JsonParser({ type: 'application/*+json' }))
``
Xprezzo and related projects are maintained by Cloudgen Wong.