Setting up a Custom Denormalizer

Oct 13, 2025 by wbrum.org 64 views

Introduction

When working with data serialization and deserialization in Symfony, you may encounter situations where you need to modify a value before sending it to the database. This can be particularly useful when dealing with sensitive information such as passwords, which should be hashed before storage. In this article, we will explore how to achieve this using a serializer and deserializer in Symfony.

Setting up a Deserializer

A deserializer is responsible for converting a serialized data into a PHP object. In Symfony, you can use the JMS Serializer bundle to achieve this. First, you need to install the bundle using Composer:

composer require jms/serializer-bundle

Next, you need to configure the deserializer in your config/services.yml file:

services:
    app.deserializer:
        class: App\Deserializer\UserDeserializer
        arguments: ['@jms_serializer']

Create a new class UserDeserializer in the App\Deserializer namespace:

// src/Deserializer/UserDeserializer.php

namespace App\Deserializer;

use JMS\Serializer\DeserializationContext;
use JMS\Serializer\DeserializerInterface;
use JMS\Serializer\Exception\InvalidArgumentException;
use Symfony\Component\Security\Core\Encoder\PasswordEncoderInterface;

class UserDeserializer implements DeserializerInterface
{
    private $passwordEncoder;

    public function __construct(PasswordEncoderInterface $passwordEncoder)
    {
        $this->passwordEncoder = $passwordEncoder;
    }

    public function deserialize($data, $type, DeserializationContext $context)
    {
        // Modify the data here, for example, hash the password
        if ($type === 'App\Entity\User') {
            $user = parent::deserialize($data, $type, $context);
            $user->setPassword($this->passwordEncoder->encodePassword($user->getPassword(), $user->getSalt()));
            return $user;
        }

        return parent::deserialize($data, $type, $context);
    }
}

Setting up a Custom Denormalizer

A denormalizer is responsible for converting a PHP object into a serialized data. You can use a custom denormalizer to modify the data before serialization. Create a new class UserDenormalizer in the App\Denormalizer namespace:

// src/Denormalizer/UserDenormalizer.php

namespace App\Denormalizer;

use JMS\Serializer\DenormalizerInterface;
use JMS\Serializer\SerializationContext;
use JMS\Serializer\Exception\InvalidArgumentException;
use Symfony\Component\Security\Core\Encoder\PasswordEncoderInterface;

class UserDenormalizer implements DenormalizerInterface
{
    private $passwordEncoder;

    public function __construct(PasswordEncoderInterface $passwordEncoder)
    {
        $this->passwordEncoder = $passwordEncoder;
    }

    public function denormalize($data, $type, $format, SerializationContext $context)
    {
        // Modify the data here, for example, hash the password
        if ($type === 'App\Entity\User') {
            $user = parent::denormalize($data, $type, $format, $context);
            $user->setPassword($this->passwordEncoder->encodePassword($user->getPassword(), $user->getSalt()));
            return $user;
        }

        return parent::denormalize($data, $type, $format, $context);
    }

    public function supportsDenormalization($data, $type, $format)
    {
        return $type === 'App\Entity\User';
    }
}

Configuring the Serializer

Finally, you need to configure the serializer to use the custom deserializer and denormalizer. Add the following configuration to your config/services.yml file:

services:
    app.serializer:
        class: JMS\Serializer\Serializer
        arguments: ['@jms_serializer']
        calls:
            - [setContext, ['@app.deserializer']]
            - [setContext, ['@app.denormalizer']]

Conclusion

Q: What is the purpose of a deserializer in Symfony?

A: A deserializer in Symfony is responsible for converting a serialized data into a PHP object. It is used to deserialize data from a variety of formats, such as JSON or XML, into a PHP object that can be used in your application.

Q: How do I configure a deserializer in Symfony?

A: To configure a deserializer in Symfony, you need to create a new class that implements the DeserializerInterface and register it as a service in your config/services.yml file. You can then use the @jms_serializer service to create a new instance of the deserializer.

Q: What is the difference between a deserializer and a denormalizer?

A: A deserializer is responsible for converting a serialized data into a PHP object, while a denormalizer is responsible for converting a PHP object into a serialized data. In other words, a deserializer is used to deserialize data from a serialized format, while a denormalizer is used to serialize data from a PHP object.

Q: How do I use a custom denormalizer in Symfony?

A: To use a custom denormalizer in Symfony, you need to create a new class that implements the DenormalizerInterface and register it as a service in your config/services.yml file. You can then use the @jms_serializer service to create a new instance of the denormalizer.

Q: Can I use both a custom deserializer and a custom denormalizer in Symfony?

A: Yes, you can use both a custom deserializer and a custom denormalizer in Symfony. You can register both services in your config/services.yml file and use them to deserialize and serialize data in your application.

Q: How do I modify a value before sending it to the database using a serializer/deserializer in Symfony?

A: To modify a value before sending it to the database using a serializer/deserializer in Symfony, you can use a custom deserializer or denormalizer to modify the data before deserialization or serialization. For example, you can use a custom deserializer to hash the user password before deserialization, or a custom denormalizer to hash the password before serialization.

Q: What are some common use cases for using a serializer/deserializer in Symfony?

A: Some common use cases for using a serializer/deserializer in Symfony include:

Deserializing data from a JSON or XML file into a PHP object
Serializing a PHP object into a JSON or XML file
Modifying data before deserialization or serialization, such as hashing passwords
Using a custom deserializer or denormalizer to deserialize or serialize data in a specific format

Q: How do I troubleshoot issues with a serializer/deserializer in Symfony?

A: To troubleshoot issues with a serializer/deserializer in Symfony, you can use the following steps:

Check the configuration of the serializer/deserializer to ensure that it is correctly configured
Use the @jms_serializer service to create a new instance of the serializer/deserializer and test it with sample data
Use the debug mode of the serializer/deserializer to see the serialized or deserialized data
Use the dump function to see the values of the variables being used in the serializer/deserializer

Conclusion

In this article, we have seen how to modify a value before sending it to the database using a serializer/deserializer in Symfony. We have also seen how to configure a deserializer and denormalizer, and how to troubleshoot issues with a serializer/deserializer. By following these steps, you can achieve this in your own Symfony application.