Posts Tagged ‘symfony2’

Sometimes you need to put a constraint on a whole class, rather than a single value. Duplicate usernames are a good example of this – you don’t want to be able to set a username to one that is already in use – but if it is in use with the user you are currently working on, you don’t want to flag it up as an error!

Lets use that as an example. You have a Username constraint and a UsernameValidator object to do the actual validation. We need to supply the validator an object, so we need to put the following method inside the Username object.

public function getTargets()
{
    return self::CLASS_CONSTRAINT;
}

This will turn the first parameter in our isValid function in the UsernameValidator class to an object.

public function isValid($user, Constraint $constraint)

Finally, you can call the constraint from your YAML validation file.

User:
    constraints:
        - nocs:UniqueUsername: ~

Normally, under user you would have getters and properties – but here we’re adding a new section named “constraints” which lists all the class constraints.

Want to use the Validation module in your Symfony2 unit tests? No problem, thanks to the ValidatorFactory, it’s relatively straight forward.

use Symfony\Component\Validator\ValidatorFactory;

class ExampleTest extends \PHPUnit_Framework_TestCase
{
    public function testSomething()
    {
        $validator = ValidatorFactory::buildDefault()->getValidator();
    }
}

Simply include the ValidatorFactory namespace and then use the class and it’s default values method to deliver you a validator, which you can then validate your objects against just as if it was in a controller.

Symfony2 has a very nice Validator component for data validation. As with most of the components, it can be used outside of the framework, but unfortunately, the documentation on how to do this is rather lacking. Indeed, even using it within Symfony but outside the controller can be difficult and this is made especially difficult if you’re using Propel because you can’t use annotations.

However, it can be done, and this tutorial will show you how.

When using the validation component somewhere other than in a Symfony2 controller (be that in an entirely different project, or just in a custom class inside the framework), the problem is that you don’t have access to the service container. So we need to create the object for ourselves.

Lets start by importing the namespace into our class.

use Symfony\Component\Validator as Validator;

This will give us quick and easy access to the Validator classes. Now we can use the ValidatorFactory to generate a validation object.

$factory = Validator\ValidatorFactory::buildDefault();
$validator = $factory->getValidator();

This is good. It means we now have a validation object that we can run against annotated classes. But what if we are using Propel and need to specify our validation rules in a YAML file?

$yamlFile = "../src/Acme/DemoBundle/Resources/config/validation.yml";
$factory = Validator\ValidatorFactory::buildDefault(array($yamlFile), false);
$validator = $factory->getValidator();

Now we can use the rules we specified in the YAML file to validate our Propel classes.

$violations = $validator->validate($model);

Splendid, we’re done. One further trick I’ll throw in with this post – what happens when you need to validate multiple objects and give a combined list of errors back? Because the list we get back is a custom object, we can’t just array_merge the two $violations list. But luckily, there is a function in the object to do this.

$violations = new Validator\ConstraintViolationList;
$firstViolations = $validator->validate($firstModel);
$secondViolations = $validator->validate($secondModel);

if ( count($firstViolations) > 0 ) {
	$violations->addAll($frstViolations);
}

if ( count($secondViolations) > 0 ) {
	$violations->addAll($secondViolations);
}

That will return you a single ConstraintViolationList that you can iterate through, containing errors from both models.

The Symfony2 framework comes with a really nice validation library and on top of the built in constraints that you can use you also have the ability to add your own custom constraints to perform any other validation checks you need to do.

The Cookbook has an article on how to create such a custom constraint, but unfortunately, as has happened a few times with the Symfony2 documentation, it misses out some fundamental and sometimes rather obscure step in order to get it working.

The problem is, it doesn’t tell you where to put the files. That leaves two options – either you have somewhere they need to be in order for Symfony to find them, or you need to fell Symfony where they are.

After hours of digging around, we eventually found the answer – in your validation.yml file you need to register the namespace and then reference that name when you call the validation rules.

Start by registering the namespace at the top of your validation.yml file.

namespaces:
  myValidator: Acme\ExampleBundle\Validator\

Lets say you have added a custom validation constraint called Postcode. When you want to invoke that from your validation rules, you need to reference the namespace you have just created.

postcode:
    - myValidator:Postcode: ~

You can then use this namespace with your custom validation rules, place them in the appropriate directory (in this case src/ExampleBundle/Validator, but you can store them somewhere else if you change the namespace – remember that Symfony2 will extract the path from the namespace).

Silex is a PHP microframework based on Symfony2 components.

With the shift in recent years to leveraging more JavaScript and front-end code in fat clients, a lot of server-side processing has been reduced to simple data relay and APIs. As a result, there have been a number of microframeworks arisen, which allow you to serve out content in a really simple and easy way.

One of the most popular is Sinatra, a micro-framework for Ruby, which is what we built Village Chief on. Indeed, Silex is inspired by Sinatra, but is PHP-based and uses some of the great components that can be found in the Symfony2 framework.

As you would expect from a microframework, it’s really easy to get started.

<?php
require_once __DIR__.'/../vendor/autoload.php';

$app = new Silex\Application();

$app->get('/hello/{name}', function ($name) use ($app) {
    return 'Hello '.$app->escape($name);
});

$app->run();

It relies heavily on Composer, a PHP dependency manager. This is a bit of a pain if you’re not already using Composer as it means you have to have yet another piece of software on your computer, but unfortunately, you’re somewhat railroaded into it as there is virtually no documentation on how to install things like Twig without it. Luckily, once you have it, it does make things easy and pain-free, so it’s probably worth going through the initial setup.

Once you’re up and running, it’s a snap to add content. We recently re-launched Maze Finance and the entire process of getting Silex up and running and migrating our existing website into it took less than two hours!