express-validator

An express.js middleware for node-validator.

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([options])); // this line must be immediately after express.bodyParser()!

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

  // VALIDATION
  // checkBody only checks req.body; none of the other req parameters
  // Similarly checkParams only checks in req.params (URL params) and
  // checkQuery only checks req.query (GET params).
  req.checkBody('postparam', 'Invalid postparam').notEmpty().isInt();
  req.checkParams('urlparam', 'Invalid urlparam').isAlpha();
  req.checkQuery('getparam', 'Invalid getparam').isInt();

  // OR assert can be used to check on all 3 types of params.
  // req.assert('postparam', 'Invalid postparam').notEmpty().isInt();
  // req.assert('urlparam', 'Invalid urlparam').isAlpha();
  // req.assert('getparam', 'Invalid getparam').isInt();

  // SANITIZATION
  // as with validation these will only validate the corresponding
  // request object
  req.sanitizeBody('postparam').toBoolean();
  req.sanitizeParams('urlparam').toBoolean();
  req.sanitizeQuery('getparam').toBoolean();

  // OR find the relevent param in all areas
  req.sanitize('postparam').toBoolean();

  var errors = req.validationErrors();
  if (errors) {
    res.send('There have been validation errors: ' + util.inspect(errors), 400);
    return;
  }
  res.json({
    urlparam: req.params.urlparam,
    getparam: req.params.getparam,
    postparam: req.params.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' } ]

$ curl http://localhost:8888/test?getparam=1&postparam=1
There have been validation errors: [
  { param: 'postparam', msg: 'Invalid postparam', value: undefined} ]

Middleware Options

####errorFormatter function(param,msg,value)

The errorFormatter option can be used to specify a function that can be used to format the objects that populate the error array that is returned in req.validationErrors(). It should return an Object that has param, msg, and value keys defined.

// In this example, the formParam value is going to get morphed into form body format useful for printing.
app.use(expressValidator({
  errorFormatter: function(param, msg, value) {
      var namespace = param.split('.')
      , root    = namespace.shift()
      , formParam = root;

    while(namespace.length) {
      formParam += '[' + namespace.shift() + ']';
    }
    return {
      param : formParam,
      msg   : msg,
      value : value
    };
  }
}));

####customValidators { "validatorName": function(value, [additional arguments]), ... }

The customValidators option can be used to add additional validation methods as needed. This option should be an Object defining the validator names and associated validation functions.

Define your custom validators:

app.use(expressValidator({
 customValidators: {
    isArray: function(value) {
        return Array.isArray(value);
    },
    gte: function(param, num) {
        return param >= num;
    }
 }
}));

Use them with their validator name:

req.checkBody('users', 'Users must be an array').isArray();
req.checkQuery('time', 'Time must be an integer great than or equal to 5').isInt().gte(5)

####customSanitizers { "sanitizerName": function(value, [additional arguments]), ... }

The customSanitizers option can be used to add additional sanitizers methods as needed. This option should be an Object defining the sanitizer names and associated functions.

Define your custom sanitizers:

app.use(expressValidator({
 customSanitizers: {
    toSanitizeSomehow: function(value) {
        var newValue = value;//some operations
        return newValue;
    },
 }
}));

Use them with their sanitizer name:

req.sanitize('address').toSanitizeSomehow();

Validation

req.check();

   req.check('testparam', 'Error Message').notEmpty().isInt();
   req.check('testparam.child', 'Error Message').isInt(); // find nested params
   req.check(['testparam', 'child'], 'Error Message').isInt(); // find nested params

Starts the validation of the specifed parameter, will look for the parameter in req in the order params, query, body, then validate, you can use 'dot-notation' or an array to access nested values.

Validators are appended and can be chained. See chriso/validator.js for available validators, or add your own.

req.assert();

Alias for req.check().

req.validate();

Alias for req.check().

req.checkBody();

Same as req.check(), but only looks in req.body.

req.checkQuery();

Same as req.check(), but only looks in req.query.

req.checkParams();

Same as req.check(), but only looks in req.params.

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>"
  }
}

Per-validation messages

You can provide an error message for a single validation with .withMessage(). This can be chained with the rest of your validation, and if you don't use it for one of the validations then it will fall back to the default.

req.assert('email', 'Invalid email')
    .notEmpty().withMessage('Email is required')
    .isEmail();
var errors = req.validationErrors();

errors:

[
  {param: 'email', msg: 'Email is required', value: '<received input>'}
  {param: 'email', msg: 'Invalid Email', value: '<received input>'}
]

Optional input

You can use the optional() method to check an input only when the input exists.

req.checkBody('email').optional().isEmail();
//if there is no error, req.body.email is either undefined or a valid mail.

Sanitizer

req.sanitize();

req.body.comment = 'a <span>comment</span>';
req.body.username = '   a user    ';

req.sanitize('comment').escape(); // returns 'a &lt;span&gt;comment&lt;/span&gt;'
req.sanitize('username').trim(); // returns 'a user'

console.log(req.body.comment); // 'a &lt;span&gt;comment&lt;/span&gt;'
console.log(req.body.username); // 'a user'

Sanitizes the specified parameter (using 'dot-notation' or array), the parameter will be updated to the sanitized result. Cannot be chained, and will return the result. See chriso/validator.js for available sanitizers, or add your own.

If the parameter is present in multiple places with the same name e.g. req.params.comment & req.query.comment, they will all be sanitized.

req.filter();

Alias for req.sanitize().

req.sanitizeBody();

Same as req.sanitize(), but only looks in req.body.

req.sanitizeQuery();

Same as req.sanitize(), but only looks in req.query.

req.sanitizeParams();

Same as req.sanitize(), but only looks in req.params.

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();

jg3526 / express-validator