muzich/vendor/gedmo/doctrine-extensions/doc/mapping.md

Mapping extension for Doctrine2

Mapping extension makes it easy to map additional metadata for event listeners. It supports Yaml, Xml and Annotation drivers which will be chosen depending on currently used mapping driver for your domain objects. Mapping extension also provides abstraction layer of EventArgs to make it possible to use single listener for different object managers like ODM and ORM.

Features:

• Mapping drivers for annotation and yaml

• Conventional extension points for metadata extraction and object manager abstraction

• Public Mapping repository is available on github

• Last update date: 2012-01-02

This article will cover the basic installation and usage of Mapping extension

Content:

• Including the extension
• Creating an extension
• Defining annotations
• Creating listener
• Attaching our listener to the event manager
• Entity with some fields to encode
• Addapting listener to support different object managers
• Customizing event adapter for specific functions

Setup and autoloading

Read the documentation or check the example code on how to setup and use the extensions in most optimized way.

Tutorial on creation of mapped extension

First, lets asume we will use Extension namespace for our additional extension library. You should create an Extension directory in your library or vendor directory. After some changes your project might look like:

project
    ...
    bootstrap.php
    vendor
        Extension
        ...
...

Now you can use any namespace autoloader class and register this namespace. We will use Doctrine\Common\ClassLoader for instance:

<?php
// path is related to boostrap.php location for example
$classLoader = new \Doctrine\Common\ClassLoader('Extension', "vendor");
$classLoader->register();

Now lets create some files which are necessary for our extension:

project
    ...
    bootstrap.php
    vendor
        Extension
            Encoder
                Mapping
                    Driver
                        Annotation.php
                    Annotations.php
                EncoderListener.php
...

Note: that extension will look for mapping in ExtensionNamespace/Mapping directory. And Driver directory should be named as Driver. These are the conventions of Mapping extension.

That is all we will need for now. As you may noticed we will create an encoding listener which could encode your fields by specified annotations. In real life it may not be useful since object will not know how to match the value.

Now lets define available annotations and setup drivers

Edit Annotations.php file:

<?php
// file: vendor/Extension/Encoder/Mapping/Annotations.php

namespace Extension\Encoder\Mapping;

use Doctrine\Common\Annotations\Annotation;

final class Encode extends Annotation
{
    public $type = 'md5';
    public $secret;
}

Edit Annotation.php driver file:

<?php
// file: vendor/Extension/Encoder/Mapping/Driver/Annotation.php

namespace Extension\Encoder\Mapping\Driver;

use Gedmo\Mapping\Driver;
use Doctrine\Common\Annotations\AnnotationReader;

class Annotation implements Driver
{
    public function readExtendedMetadata($meta, array &$config) {
        // load our available annotations
        require_once __DIR__ . '/../Annotations.php';
        $reader = new AnnotationReader();

        $class = $meta->getReflectionClass();
        // check only property annotations
        foreach ($class->getProperties() as $property) {
            // skip inherited properties
            if ($meta->isMappedSuperclass && !$property->isPrivate() ||
                $meta->isInheritedField($property->name) ||
                isset($meta->associationMappings[$property->name]['inherited'])
            ) {
                continue;
            }
            // now lets check if property has our annotation
            if ($encode = $reader->getPropertyAnnotation($property, 'Extension\Encoder\Mapping\Encode')) {
                $field = $property->getName();
                // check if field is mapped
                if (!$meta->hasField($field)) {
                    throw new \Exception("Field is not mapped as object property");
                }
                // allow encoding only strings
                if (!in_array($encode->type, array('sha1', 'md5'))) {
                    throw new \Exception("Invalid encoding type supplied");
                }
                // validate encoding type
                $mapping = $meta->getFieldMapping($field);
                if ($mapping['type'] != 'string') {
                    throw new \Exception("Only strings can be encoded");
                }
                // store the metadata
                $config['encode'][$field] = array(
                    'type' => $encode->type,
                    'secret' => $encode->secret
                );
            }
        }
    }
}

Finally, lets create the listener

Note: this version of listener will support only ORM Entities

<?php
// file: vendor/Extension/Encoder/EncoderListener.php

namespace Extension\Encoder;

use Doctrine\Common\EventArgs;
use Gedmo\Mapping\MappedEventSubscriber;

class EncoderListener extends MappedEventSubscriber
{
    public function getSubscribedEvents()
    {
        return array(
            'onFlush',
            'loadClassMetadata'
        );
    }

    public function loadClassMetadata(EventArgs $args)
    {
        // this will check for our metadata
        $this->loadMetadataForObjectClass(
            $args->getEntityManager(),
            $args->getClassMetadata()
        );
    }

    public function onFlush(EventArgs $args)
    {
        $em = $args->getEntityManager();
        $uow = $em->getUnitOfWork();

        // check all pending updates
        foreach ($uow->getScheduledEntityUpdates() as $object) {
            $meta = $em->getClassMetadata(get_class($object));
            // if it has our metadata lets encode the properties
            if ($config = $this->getConfiguration($em, $meta->name)) {
                $this->encode($em, $object, $config);
            }
        }
        // check all pending insertions
        foreach ($uow->getScheduledEntityInsertions() as $object) {
            $meta = $em->getClassMetadata(get_class($object));
            // if it has our metadata lets encode the properties
            if ($config = $this->getConfiguration($em, $meta->name)) {
                $this->encode($em, $object, $config);
            }
            // recalculate changeset
            $em->getUnitOfWork()->recomputeSingleEntityChangeSet($meta, $object);
        }
    }

    protected function getNamespace()
    {
        // mapper must know the namespace of extension
        return __NAMESPACE__;
    }

    private function encode($em, $object, $config)
    {
        $meta = $em->getClassMetadata(get_class($object));
        foreach ($config['encode'] as $field => $options) {
            $value = $meta->getReflectionProperty($field)->getValue($object);
            $method = $options['type'];
            $encoded = $method($options['secret'].$value);
            $meta->getReflectionProperty($field)->setValue($object, $encoded);
        }
        // recalculate changeset
        $em->getUnitOfWork()->recomputeSingleEntityChangeSet($meta, $object);
    }
}

Our Encoder extension is ready, now if we want to test it, we need to attach our EncoderListener to the EventManager and create an entity with some fields to encode.

Attaching the EncoderListener

<?php
$evm = new \Doctrine\Common\EventManager();
$encoderListener = new \Extension\Encoder\EncoderListener;
$evm->addEventSubscriber($encoderListener);
// now this event manager should be passed to entity manager constructor

Create an entity with some fields to encode

<?php
namespace YourNamespace\Entity;

use Doctrine\ORM\Mapping as ORM;
use Extension\Encoder\Mapping as EXT;

/**
 * @ORM\Table(name="test_users")
 * @ORM\Entity
 */
class User
{
    /**
     * @ORM\Column(type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue
     */
    private $id;

    /**
     * @EXT\Encode(type="sha1", secret="xxx")
     * @ORM\Column(length=64)
     */
    private $name;

    /**
     * @EXT\Encode(type="md5")
     * @ORM\Column(length=32)
     */
    private $password;

    public function setName($name)
    {
        $this->name = $name;
    }

    public function getName()
    {
        return $this->name;
    }

    public function setPassword($password)
    {
        $this->password = $password;
    }

    public function getPassword()
    {
        return $this->password;
    }
}

If you will try to create a new User you will get encoded fields in database.

Adapting listener to support other object managers

Now the event adapter comes into play, lets slightly modify our listener:

<?php
// file: vendor/Extension/Encoder/EncoderListener.php

use Doctrine\Common\EventArgs;
use Gedmo\Mapping\MappedEventSubscriber;
use Gedmo\Mapping\Event\AdapterInterface as EventAdapterInterface;

class EncoderListener extends MappedEventSubscriber
{
    public function getSubscribedEvents()
    {
        return array(
            'onFlush',
            'loadClassMetadata'
        );
    }

    public function loadClassMetadata(EventArgs $args)
    {
        $ea = $this->getEventAdapter($args);
        // this will check for our metadata
        $this->loadMetadataForObjectClass(
            $ea->getObjectManager(),
            $args->getClassMetadata()
        );
    }

    public function onFlush(EventArgs $args)
    {
        $ea = $this->getEventAdapter($args);
        $om = $ea->getObjectManager();
        $uow = $om->getUnitOfWork();

        // check all pending updates
        foreach ($ea->getScheduledObjectUpdates($uow) as $object) {
            $meta = $om->getClassMetadata(get_class($object));
            // if it has our metadata lets encode the properties
            if ($config = $this->getConfiguration($om, $meta->name)) {
                $this->encode($ea, $object, $config);
            }
        }
        // check all pending insertions
        foreach ($ea->getScheduledObjectInsertions($uow) as $object) {
            $meta = $om->getClassMetadata(get_class($object));
            // if it has our metadata lets encode the properties
            if ($config = $this->getConfiguration($om, $meta->name)) {
                $this->encode($ea, $object, $config);
            }
            // recalculate changeset
            $ea->recomputeSingleObjectChangeSet($uow, $meta, $object);
        }
    }

    protected function getNamespace()
    {
        // mapper must know the namespace of extension
        return __NAMESPACE__;
    }

    private function encode(EventAdapterInterface $ea, $object, $config)
    {
        $om = $ea->getObjectManager();
        $meta = $om->getClassMetadata(get_class($object));
        $uow = $om->getUnitOfWork();
        foreach ($config['encode'] as $field => $options) {
            $value = $meta->getReflectionProperty($field)->getValue($object);
            $method = $options['type'];
            $encoded = $method($options['secret'].$value);
            $meta->getReflectionProperty($field)->setValue($object, $encoded);
        }
        // recalculate changeset
        $ea->recomputeSingleObjectChangeSet($uow, $meta, $object);
    }
}

Note: event adapter uses EventArgs to recognize with which manager we are dealing with. It also uses event arguments to retrieve manager and transforms the method call in its way. You can extend the event adapter in order to add some specific methods for each manager.

Thats it, now it will work on ORM and ODM object managers.

Customizing event adapter for specific functions

In most cases event listener will need specific functionality which will differ for every object manager. For instance, a query to load users will differ. The example bellow will illustrate how to handle such situations. You will need to extend default ORM and ODM event adapters to implement specific functions which will be available through the event adapter. First we will need to follow the mapping convention to use those extension points.

Extending default event adapters

Update your directory structure:

project
    ...
    bootstrap.php
    vendor
        Extension
            Encoder
                Mapping
                    Driver
                        Annotation.php
                    Event
                        Adapter
                            ORM.php
                            ODM.php
                    Annotations.php
                EncoderListener.php
...

Now Mapping extension will automatically create event adapter instances from the extended ones.

Create extended ORM event adapter:

<?php
// file: vendor/Extension/Encoder/Mapping/Event/Adapter/ORM.php

namespace Extension\Encoder\Mapping\Event\Adapter;

use Gedmo\Mapping\Event\Adapter\ORM as BaseAdapterORM;

class ORM extends BaseAdapterORM
{
    public function someSpecificMethod()
    {

    }
}

Create extended ODM event adapter:

<?php
// file: vendor/Extension/Encoder/Mapping/Event/Adapter/ODM.php

namespace Extension\Encoder\Mapping\Event\Adapter;

use Gedmo\Mapping\Event\Adapter\ODM as BaseAdapterODM;

class ODM extends BaseAdapterODM
{
    public function someSpecificMethod()
    {
 
    }
}

It would be useful to make a common interface for those extended adapters. Now every possible requirement is fullfilled and this may be useful.

Any suggestions on improvements are very welcome