express-body-parser-error-handler

express-body-parser-error-handler

middleware to be set right after body parser in order to handle all body parser errors and return 4xx responses to the client

About

99.9% of the time your going to use body parser on your express server application , even if your going to use express.json,raw,text or urlencoded under the hood it also uses body parser express source code

There’re multiple kinds of errors raised by body-parser. They involve sending bad headers or data that are not accepted by it, or canceling requests before all the data is read. Various 400 series error status codes will be sent as the response along with the corresponding error messages and stack trace the problem is when errors thrown from this middleware you need to handle them by yourself and all errors thrown from body parser are usually 4xx errors caused by client

for example:

Type	Code	description
encoding.unsupported	415	content encoding unsupported
entity.parse.failed	400
entity.verify.failed	403
request.aborted	400	request is aborted by the client before reading the body has finished
request.size.invalid	400	request size did not match content length
stream.encoding.set	500	stream encoding should not be set
parameters.too.many	413
charset.unsupported	415	unsupported charset “BOGUS”
encoding.unsupported	415	unsupported content encoding “bogus”
entity.too.large	413

use this package if you don't want to handle them yourself :-)

Install

$ npm i express-body-parser-error-handler

Example

 request(app)
        .post('/')
        .set('Content-Type', 'application/json')
        .send('{ email: \'email\', password: \'password\'')  //  <==== missing "}"  - invalid json   
        .expect(400, function (err, res) {
          expect(JSON.parse(res.text).message).to.equal(
   ====>        'Body Parser failed to parse request --> Unexpected token e in JSON at position 2'
          )
        })

Usage Example

const bodyParserErrorHandler = require('express-body-parser-error-handler')
const { urlencoded, json } = require('body-parser')
const express = require('express')
const app = express();
router.route('/').get(function (req, res) {
    return res.json({message:"🚀"});
});

// body parser initilization
app.use(urlencoded({extended: false, limit: '250kb'}));
app.use('/', json({limit: '250kb'}));

// body parser error handler
app.use(bodyParserErrorHandler());
app.use(router);
...

Configuration

onError - function(err, req, res) => { }

Custom on error callback useful if you want to log the error message or send metrics

app.use(bodyParserErrorHandler({
    onError = (err, req, res) => {
        ...
    }
}))

errorMessage - function(err) => { }

default:

errorMessage = (err) => {
    return `Body Parser failed to parse request --> ${err.message}`
}

app.use(bodyParserErrorHandler({
    errorMessage = (err) => {
        ...
    }
}))

License

MIT ©

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