Question

I am right now getting myself more and more familiar with Zend Framework 2 and in the meantime I was getting myself updated with the validation part in Zend Framework 2. I have seen few examples how to validate the data from the database using Zend Db adapter, for example the code from the Zend Framework 2 official website:

//Check that the username is not present in the database
$validator = new Zend\Validator\Db\NoRecordExists(
    array(
        'table' => 'users',
        'field' => 'username'
    )
);
if ($validator->isValid($username)) {
    // username appears to be valid
} else {
    // username is invalid; print the reason
    $messages = $validator->getMessages();
    foreach ($messages as $message) {
        echo "$message\n";
    }
}

Now my question is how can do the validation part?

For example, I need to validate a name before inserting into database to check that the same name does not exist in the database, I have updated Zend Framework 2 example Album module to use Doctrine 2 to communicate with the database and right now I want to add the validation part to my code.

Let us say that before adding the album name to the database I want to validate that the same album name does not exist in the database.

Any information regarding this would be really helpful!

Answer 1

I had the same problem and solved it this way:

1. Create a custom validator class, name it something like NoEntityExists (or whatever you want).
2. Extend Zend\Validator\AbstractValidator
3. Provide a getter and setter for Doctrine\ORM\EntityManager
4. Provide some extra getters and setters for options (entityname, …)
5. Create an isValid($value) method that checks if a record exists and returns a boolean
6. To use it, create a new instance of it, assign the EntityManager and use it just like any other validator.

To get an idea of how to implement the validator class, check the validators that already exist (preferably a simple one like Callback or GreaterThan).

Hope I could help you.

// Edit: Sorry, I’m late 😉

So here is a quite advanced example of how you can implement such a validator.

Note that I added a translate() method in order to catch language strings with PoEdit (a translation helper tool that fetches such strings from the source codes and puts them into a list for you). If you’re not using gettext(), you can problably skip that.

Also, this was one of my first classes with ZF2, I wouldn’t put this into the Application module again. Maybe, create a new module that fits better, for instance MyDoctrineValidator or so.

This validator gives you a lot of flexibility as you have to set the query before using it. Of course, you can pre-define a query and set the entity, search column etc. in the options. Have fun!

<?php
namespace Application\Validator\Doctrine;

use Zend\Validator\AbstractValidator;
use Doctrine\ORM\EntityManager;

class NoEntityExists extends AbstractValidator
{
    const ENTITY_FOUND = 'entityFound';

    protected $messageTemplates = array();

    /**
     * @var EntityManager
     */
    protected $entityManager;

    /**
     * @param string
     */
    protected $query;

    /**
     * Determines if empty values (null, empty string) will <b>NOT</b> be included in the check.
     * Defaults to true
     * @var bool
     */
    protected $ignoreEmpty = true;

    /**
     * Dummy to catch messages with PoEdit...
     * @param string $msg
     * @return string
     */
    public function translate($msg)
    {
        return $msg;
    }

    /**
     * @return the $ignoreEmpty
     */
    public function getIgnoreEmpty()
    {
        return $this->ignoreEmpty;
    }

    /**
     * @param boolean $ignoreEmpty
     */
    public function setIgnoreEmpty($ignoreEmpty)
    {
        $this->ignoreEmpty = $ignoreEmpty;
        return $this;
    }

    /**
     *
     * @param unknown_type $entityManager
     * @param unknown_type $query
     */
    public function __construct($entityManager = null, $query = null, $options = null)
    {
        if(null !== $entityManager)
            $this->setEntityManager($entityManager);
        if(null !== $query)
            $this->setQuery($query);

        // Init messages
        $this->messageTemplates[self::ENTITY_FOUND] = $this->translate('There is already an entity with this value.');

        return parent::__construct($options);
    }

    /**
     *
     * @param EntityManager $entityManager
     * @return \Application\Validator\Doctrine\NoEntityExists
     */
    public function setEntityManager(EntityManager $entityManager)
    {
        $this->entityManager = $entityManager;
        return $this;
    }

    /**
     * @return the $query
     */
    public function getQuery()
    {
        return $this->query;
    }

    /**
     * @param field_type $query
     */
    public function setQuery($query)
    {
        $this->query = $query;
        return $this;
    }

    /**
     * @return \Doctrine\ORM\EntityManager
     */
    public function getEntityManager()
    {
        return $this->entityManager;
    }

    /**
     * (non-PHPdoc)
     * @see \Zend\Validator\ValidatorInterface::isValid()
     * @throws Exception\RuntimeException() in case EntityManager or query is missing
     */
    public function isValid($value)
    {
        // Fetch entityManager
        $em = $this->getEntityManager();

        if(null === $em)
            throw new Exception\RuntimeException(__METHOD__ . ' There is no entityManager set.');

        // Fetch query
        $query = $this->getQuery();

        if(null === $query)
            throw new Exception\RuntimeException(__METHOD__ . ' There is no query set.');

        // Ignore empty values?
        if((null === $value || '' === $value) && $this->getIgnoreEmpty())
            return true;

        $queryObj = $em->createQuery($query)->setMaxResults(1);

        $entitiesFound = !! count($queryObj->execute(array(':value' => $value)));

        // Set Error message
        if($entitiesFound)
            $this->error(self::ENTITY_FOUND);

        // Valid if no records are found -> result count is 0
        return ! $entitiesFound;
    }
}