get-validated

A simple, flexible validation middleware to make validation less painful

What is it?

get-validated is not a validation framework. Rather, it is a simple express middleware that allows you to integrate many validation frameworks into your express app in a consistent manner.

It comes with the validator framework built in.

All validation errors are combined and put into a single ValidationError object with a status|code of 412. And the messages property is set to an object keyed by parameter name of the current errors.

Basic Usage

Initial set up for a our little example express app.

var express = require('express'),
    router  = express.Router(),
    get_validated = require('get-validated'),
    validations
;

Once we have our express app all set then we create our validations object.

 
validations = get_validated({
  'param1': function (value, container, done) {
      // perform validation here.
      // `value` will be the return from req.param('param1')
      // `container` will be whatever is passed to `get_validated`
      //          `options` parameter as the `options.container` object
      //          It will also have a `helpers` object that will have
      //          the [`validator`](https://github.com/chriso/validator.js)
      //          framework attached.
      if (!container.helpers.isInt(value)) {
        return done(":name must be an integer, ':value' given");
      }
      if (value < 123) {
        return done(":name must be greater than 123, ':value' given");
      }
      
      return done(null, container.helpers.toInt(value));
  },
  'param2': function (value, container, done) {
      // you will have access to the current request via
      // `container.req`
      var req = container.req;
      
      // You can do async things!
      req.db.query('SELECT * FROM something where id = ?', [value],
        function (err, rows) {
          // ... do some validation here...
          return done(':name value of :value could not be found!');
      }
  }
});

Now that we have our validations object we can use it in a few different ways.

1. Apply it to the route and then use req.getValidated within individual route handlers.

router.use(validations);
 
router.route('/').post(function (req, res, next) {
  req.getValidated(['param1','param2']).then(function (validated) {
      //do something with the parameters.
      console.log("Param1 = %s", validated.param1);
      console.log("Param2 = %s", validated.param2);
  // if you catch the error in this way a 412 error will be propagated
  // to the client.
  }).catch(next);
});
 

1. Use it as route specific middleware to validate parameters used by that route. Note: If you use this method then all errors are sent to next(err) to be handled by your app's current error handler.

 
router.route('/').post([
  validations.validate(['param1', 'param2']),
  function (req, res) {
    //do something with the parameters.
    console.log("Param1 = %s", req.validated.param1);
    console.log("Param2 = %s", req.validated.param2);
  }
]);

Advanced Usage

Now one of the fun parts of this module is that you can integrate pretty much any validations framework that you want with it. Here is a list of some:

• Composed Validations
• Joi
• validate-it

I'm going to use Composed Validations here to show how you integrate a validation libray, at least one way to do it.

In Composed Validations examples they show an address validator, so let's work with that.

 
var cv = require('composed-validations');
 
var addressValidator = cv.struct()
    .validate('street', cv.presence())
    .validate('zip', cv.format(/\d{5}/) // silly zip format
    .validate('city', cv.presence()
    .validate('state', cv.presence();

So now that we have our address validator we can integrate it directly into our validations object like so

var options = {
    container: {
        'cv': cv,  // we don't have to integrate but just for fun we will.
        'addressValidator': addressValidator
    }
};
 
var validations = get_validated({
    'address': function (value, container, done) {
        // we're going to ignore the value here because we have a complex type,
        // but we'll get our reference to request to pull the values from there.
        var req = container.req;
        
        var address = {
            street: req.param('street'),
            zip: req.param('zip'),
            city: req.param('city'),
            state: req.param('state')
        };
        // and there we go, we don't have to worry about the error at this point
        // because the validation handler will receive the thrown execption and 
        // turn it into a ValidationError appropriately.
        container.addressValidator.test(address);
        
        //but we do have to send our fancy validated address down to the user function.
        return done(null, address);
    }
}, options);

After we have our validations object we can use it just like any other one.

router.route('/').post([
    validations.validate('address'),
    function (req, res, next) {
        // And our address information will be conveniently placed into the validated object.
        console.log ("Address: %j", req.validated.address);
        // do other stuff...
    }
]);

options

• container - This is your integration point. Anything you attach here will be sent along to your validation functions as the container object.
• validateAction - Don't like my validation handling function? Then write your own. Debugging is your responsibility.
• renderer - get-validate comes with a very simple message renderer that recognizes two tags (':name' and ':value'), provide your own function if you like.

todo

• route specific middleware
• more usage examples showing how to use the joi and composed-validations