express-validator

An express.js middleware for node-validator.

This is basically a copy of a gist by node-validator author chriso.

Installation

npm install express-validator

Usage

var util = require('util'),
    express = require('express'),
    expressValidator = require('express-validator'),
    app = express.createServer();

app.use(express.bodyParser());
app.use(expressValidator);

app.post('/:urlparam', function(req, res) {

  req.assert('postparam', 'Invalid postparam').notEmpty().isInt();
  req.assert('getparam', 'Invalid getparam').isInt();
  req.assert('urlparam', 'Invalid urlparam').isAlpha();

  req.sanitize('postparam').toBoolean();

  var errors = req.validationErrors();
  if (errors) {
    res.send('There have been validation errors: ' + util.inspect(errors), 500);
    return;
  }
  res.json({
    urlparam: req.param('urlparam'),
    getparam: req.param('getparam'),
    postparam: req.param('postparam')
  });
});

app.listen(8888);

Which will result in:

$ curl -d 'postparam=1' http://localhost:8888/test?getparam=1
{"urlparam":"test","getparam":"1","postparam":true}

$ curl -d 'postparam=1' http://localhost:8888/t1est?getparam=1
There have been validation errors: [
  { param: 'urlparam', msg: 'Invalid urlparam', value: 't1est' } ]

$ curl -d 'postparam=1' http://localhost:8888/t1est?getparam=1ab
There have been validation errors: [
  { param: 'getparam', msg: 'Invalid getparam', value: '1ab' },
  { param: 'urlparam', msg: 'Invalid urlparam', value: 't1est' } ]

You can extend the Validator and Filter objects to add custom validation and sanitization methods:

var expressValidator = require('express-validator');

expressValidator.Filter.prototype.toLowerCase = function(){
  this.modify(this.str.toLowerCase());
  return this.str;
};

Validation errors

You have two choices on how to get the validation errors:

req.assert('email', 'required').notEmpty();
req.assert('email', 'valid email required').isEmail();
req.assert('password', '6 to 20 characters required').len(6, 20);

var errors = req.validationErrors();
var mappedErrors = req.validationErrors(true);

errors:

[
  {param: "email", msg: "required", value: "<received input>"},
  {param: "email", msg: "valid email required", value: "<received input>"},
  {param: "password", msg: "6 to 20 characters required", value: "<received input>"}
]

mappedErrors:

{
  email: {
    param: "email",
    msg: "valid email required",
    value: "<received input>"
  },
  password: {
    param: "password",
    msg: "6 to 20 characters required",
    value: "<received input>"
  }
}

Nested input data

Example:

<input name="user[fields][email]" />

Provide an array instead of a string:

req.assert(['user', 'fields', 'email'], 'valid email required').isEmail();
var errors = req.validationErrors();
console.log(errors);

Output:

[
  {
    param: "user_fields_email",
    msg: "valid email required",
    value: "<received input>"
  }
]

Alternatively you can use dot-notation to specify nested fields to be checked:

req.assert(['user', 'fields', 'email'], 'valid email required').isEmail();

Regex routes

Express allows you to define regex routes like:

app.get(/\/test(\d+)/, function() {});

You can validate the extracted matches like this:

req.assert(0, 'Not a three-digit integer.').len(3, 3).isInt();

Changelog

v0.3.0

• req.validationErrors() now returns null instead of false if there are no errors.

v0.2.4

• Support for regex routes (@Cecchi)

v0.2.3

• Fix checkHeader() (@pimguilherme)

v0.2.2

• Add dot-notation for nested input (@sharonjl)
• Add validate() alias for check()

v0.2.1

• Fix chaining validators (@rapee)

v0.2.0

• Added validationErrors() method (by @orfaust)
• Added support for nested form fields (by @orfaust)
• Added test cases

v0.1.3

• Readme update

v0.1.2

• Expose Filter and Validator instances to allow adding custom methods

v0.1.1

• Use req.param() method to get parameter values instead of accessing req.params directly.
• Remove req.mixinParams() method.

v0.1.0

• Initial release

Contributors

• Christoph Tavan dev@tavan.de - Wrap the gist in an npm package
• @orfaust - Add validationErrors() and nested field support

License

Copyright (c) 2010 Chris O'Hara cohara87@gmail.com, MIT License