# express-validator
[](https://www.npmjs.com/package/express-validator)
[](http://travis-ci.org/ctavan/express-validator)
[](https://david-dm.org/ctavan/express-validator)
[](https://coveralls.io/github/ctavan/express-validator?branch=master)
An [express.js]( https://github.com/visionmedia/express ) middleware for
[node-validator]( https://github.com/chriso/validator.js ).
- [Installation](#installation)
- [Usage](#usage)
- [Middleware options](#middleware-options)
- [Validation](#validation)
- [Validation by schema](#validation-by-schema)
- [Validation result](#validation-result)
+ [Result API](#result-api)
+ [Deprecated API](#deprecated-api)
+ [String formatting for error messages](#string-formatting-for-error-messages)
+ [Per-validation messages](#per-validation-messages)
- [Optional input](#optional-input)
- [Sanitizer](#sanitizer)
- [Regex routes](#regex-routes)
- [TypeScript](#typescript)
- [Changelog](#changelog)
- [License](#license)
## Installation
```
npm install express-validator
```
## Usage
```javascript
var util = require('util'),
bodyParser = require('body-parser'),
express = require('express'),
expressValidator = require('express-validator'),
app = express();
app.use(bodyParser.json());
app.use(expressValidator([options])); // this line must be immediately after any of the bodyParser middlewares!
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();
// Alternatively use `var result = yield req.getValidationResult();`
// when using generators e.g. with co-express
req.getValidationResult().then(function(result) {
if (!result.isEmpty()) {
res.status(400).send('There have been validation errors: ' + util.inspect(result.array()));
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 must build the error objects used in the validation result returned by `req.getValidationResult()`.
It should return an `Object` that has `param`, `msg`, and `value` keys defined.
```javascript
// 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:
```javascript
app.use(expressValidator({
customValidators: {
isArray: function(value) {
return Array.isArray(value);
},
gte: function(param, num) {
return param >= num;
}
}
}));
```
Use them with their validator name:
```javascript
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:
```javascript
app.use(expressValidator({
customSanitizers: {
toSanitizeSomehow: function(value) {
var newValue = value;//some operations
return newValue;
},
}
}));
```
Use them with their sanitizer name:
```javascript
req.sanitize('address').toSanitizeSomehow();
```
## Validation
#### req.check();
```javascript
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.
If a validator takes in params, you would call it like `req.assert('reqParam').contains('thisString');`.
Validators are appended and can be chained. See [chriso/validator.js](https://github.com/chriso/validator.js) for available validators, or [add your own](#customvalidators).
#### req.assert();
Alias for [req.check()](#reqcheck).
#### req.validate();
Alias for [req.check()](#reqcheck).
#### req.checkBody();
Same as [req.check()](#reqcheck), but only looks in `req.body`.
#### req.checkQuery();
Same as [req.check()](#reqcheck), but only looks in `req.query`.
#### req.checkParams();
Same as [req.check()](#reqcheck), but only looks in `req.params`.
#### req.checkHeaders();
Only checks `req.headers`. This method is not covered by the general `req.check()`.
#### req.checkCookies();
Only checks `req.cookies`. This method is not covered by the general `req.check()`.
## Validation by Schema
Alternatively you can define all your validations at once using a simple schema.
Schema validation will be used if you pass an object to any of the validator methods.
You may pass per-validator error messages with the `errorMessage` key.
Validator options may be passed via `options` key as an array when various values are needed,
or as a single non-null value otherwise.
```javascript
req.checkBody({
'email': {
optional: {
options: { checkFalsy: true } // or: [{ checkFalsy: true }]
},
isEmail: {
errorMessage: 'Invalid Email'
}
},
'password': {
notEmpty: true,
matches: {
options: ['example', 'i'] // pass options to the validator with the options property as an array
// options: [/example/i] // matches also accepts the full expression in the first parameter
},
errorMessage: 'Invalid Password' // Error message for the parameter
},
'name.first': { //
optional: true, // won't validate if field is empty
isLength: {
options: [{ min: 2, max: 10 }],
errorMessage: 'Must be between 2 and 10 chars long' // Error message for the validator, takes precedent over parameter message
},
errorMessage: 'Invalid First Name'
}
});
```
You can also define a specific location to validate against in the schema by adding `in` parameter as shown below:
```javascript
req.check({
'email': {
in: 'query',
notEmpty: true,
isEmail: {
errorMessage: 'Invalid Email'
}
}
});
```
Please remember that the `in` attribute will have always highest priority. This mean if you use `in: 'query'` then checkQuery() will be called inside even if you do `checkParams()` or `checkBody()`. For example, all of these calls will check query params for email param:
```javascript
var schema = {
'email': {
in: 'query',
notEmpty: true,
isEmail: {
errorMessage: 'Invalid Email'
}
},
'password': {
notEmpty: true,
matches: {
options: ['example', 'i'] // pass options to the validator with the options property as an array
// options: [/example/i] // matches also accepts the full expression in the first parameter
},
errorMessage: 'Invalid Password' // Error message for the parameter
}
};
req.check(schema); // will check 'password' no matter where it is but 'email' in query params
req.checkQuery(schema); // will check 'password' and 'email' in query params
req.checkBody(schema); // will check 'password' in body but 'email' in query params
req.checkParams(schema); // will check 'password' in path params but 'email' in query params
req.checkHeaders(schema); // will check 'password' in headers but 'email' in query params
```
Currently supported location are `'body', 'params', 'query', 'headers'`. If you provide a location parameter that is not supported, the validation process for current parameter will be skipped.
## Validation result
### Result API
The method `req.getValidationResult()` returns a Promise which resolves to a result object.
```js
req.assert('email', 'required').notEmpty();
req.assert('email', 'valid email required').isEmail();
req.assert('password', '6 to 20 characters required').len(6, 20);
req.getValidationResult().then(function(result) {
// do something with the validation result
});
```
The API for the result object is the following:
#### `result.isEmpty()`
Returns a boolean determining whether there were errors or not.
#### `result.useFirstErrorOnly()`
Sets the `firstErrorOnly` flag of this result object, which modifies the way
other methods like `result.array()` and `result.mapped()` work.
This method is chainable, so the following is OK:
```js
result.useFirstErrorOnly().array();
```
#### `result.array()`
Returns an array of errors.
All errors for all validated parameters will be included, unless you specify that you want only the first error of each param by invoking `result.useFirstErrorOnly()`.
```javascript
var errors = result.array();
// errors will now contain something like this:
[
{param: "email", msg: "required", value: ""},
{param: "email", msg: "valid email required", value: ""},
{param: "password", msg: "6 to 20 characters required", value: ""}
]
```
#### `result.mapped()`
Returns an object of errors, where the key is the parameter name, and the value is an error object as returned by the error formatter.
Because of historical reasons, by default this method will return the last error of each parameter.
You can change this behavior by invoking `result.useFirstErrorOnly()`, so the first error is returned instead.
```javascript
var errors = result.mapped();
// errors will now be similar to this:
{
email: {
param: "email",
msg: "valid email required",
value: ""
},
password: {
param: "password",
msg: "6 to 20 characters required",
value: ""
}
}
```
#### `result.throw()`
If there are errors, throws an `Error` object which is decorated with the same API as the validation result object.
Useful for dealing with the validation errors in the `catch` block of a `try..catch` or promise.
```js
try {
result.throw();
res.send('success!');
} catch (e) {
console.log(e.array());
res.send('oops, validation failed!');
}
```
### Deprecated API
The following methods are deprecated.
While they work, their API is unflexible and sometimes return weird results if compared to the bleeding edge `req.getValidationResult()`.
Additionally, these methods may be removed in a future version.
#### `req.validationErrors([mapped])`
Returns synchronous errors in the form of an array, or an object that maps parameter to error in case `mapped` is passed as `true`.
If there are no errors, the returned value is `false`.
```js
var errors = req.validationErrors();
if (errors) {
// do something with the errors
}
```
#### `req.asyncValidationErrors([mapped])`
Returns a promise that will either resolve if no validation errors happened, or reject with an errors array/mapping object. For reference on this, see `req.validationErrors()`.
```js
req.asyncValidationErrors().then(function() {
// all good here
}, function(errors) {
// damn, validation errors!
});
```
### String formatting for error messages
Error messages can be customized to include both the value provided by the user, as well as the value of any parameters passed to the validation function, using a standard string replacement format:
`%0` is replaced with user input
`%1` is replaced with the first parameter to the validator
`%2` is replaced with the second parameter to the validator
etc...
Example:
```javascript
req.assert('number', '%0 is not an integer').isInt();
req.assert('number', '%0 is not divisible by %1').isDivisibleBy(5);
```
*Note:* string replacement does **not** work with the `.withMessage()` syntax. If you'd like to have per-validator error messages with string formatting, please use the [Validation by Schema](#validation-by-schema) method instead.
### 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.
```javascript
req.assert('email', 'Invalid email')
.notEmpty().withMessage('Email is required')
.isEmail();
req.getValidationResult()
.then(function(result){
console.log(result.array());
});
```
prints:
```javascript
[
{param: 'email', msg: 'Email is required', value: ''}
{param: 'email', msg: 'Invalid Email', value: ''}
]
```
## Optional input
You can use the `optional()` method to skip validation. By default, it only skips validation if the key does not exist on the request object. If you want to skip validation based on the property being falsy (null, undefined, etc), you can pass in `{ checkFalsy: true }`.
```javascript
req.checkBody('email').optional().isEmail();
//if there is no error, req.body.email is either undefined or a valid mail.
```
## Sanitizer
#### req.sanitize();
```javascript
req.body.comment = 'a comment';
req.body.username = ' a user ';
req.sanitize('comment').escape(); // returns 'a <span>comment</span>'
req.sanitize('username').trim(); // returns 'a user'
console.log(req.body.comment); // 'a <span>comment</span>'
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](https://github.com/chriso/validator.js) for available sanitizers, or [add your own](#customsanitizers).
If a sanitizer takes in params, you would call it like `req.sanitize('reqParam').whitelist(['a', 'b', 'c']);`.
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()](#reqsanitize).
#### req.sanitizeBody();
Same as [req.sanitize()](#reqsanitize), but only looks in `req.body`.
#### req.sanitizeQuery();
Same as [req.sanitize()](#reqsanitize), but only looks in `req.query`.
#### req.sanitizeParams();
Same as [req.sanitize()](#reqsanitize), but only looks in `req.params`.
#### req.sanitizeHeaders();
Only sanitizes `req.headers`. This method is not covered by the general `req.sanitize()`.
#### req.sanitizeCookies();
Only sanitizes `req.cookies`. This method is not covered by the general `req.sanitize()`.
## Regex routes
Express allows you to define regex routes like:
```javascript
app.get(/\/test(\d+)/, function() {});
```
You can validate the extracted matches like this:
```javascript
req.assert(0, 'Not a three-digit integer.').len(3, 3).isInt();
```
## TypeScript
If you have been using this library with [TypeScript](http://www.typescriptlang.org/),
you must have been using the type definitions from [DefinitelyTyped](https://github.com/DefinitelyTyped/DefinitelyTyped/blob/e2af6d0/express-validator/express-validator.d.ts).
However, as of v3.1.0, the type definitions are shipped with the library.
So please uninstall the typings from DT. Otherwise they may cause conflicts
## Changelog
Check the [GitHub Releases page](https://github.com/ctavan/express-validator/releases).
## License
Copyright (c) 2010 Chris O'Hara , MIT License