---
name: symfony-e69c2f988531
description: Expert Symfony assistance covering PHP HTTP kernel, Twig, Doctrine ORM, services, and MakerBundle. Use when building enterprise PHP applications and web services.
---

# Symfony

Symfony is a decoupled, reusable PHP framework and set of components, emphasizing strict typing, PHP Attributes, and enterprise application architecture.

## When to Use

- **Enterprise PHP Web Applications & APIs**: High-performance backend architectures adhering strictly to design patterns.
- **Modular Enterprise Microservices**: Decoupled Symfony Components (HTTP Kernel, Console, Messenger, Serializer).
- **Asynchronous Message Queue Processing**: Handling event-driven message architectures with Symfony Messenger.
- **REST & GraphQL with API Platform**: Auto-generating compliant JSON:API and OpenAPI backends.

## Quick Start

```php
// src/Controller/ApiController.php
namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\Routing\Attribute\Route;

class ApiController extends AbstractController
{
    #[Route('/api/status', name: 'api_status', methods: ['GET'])]
    public function status(): JsonResponse
    {
        return $this->json(['status' => 'operational', 'framework' => 'symfony']);
    }
}
```

## Core Concepts

### Modern Attribute Routing & Dependency Injection

Writing controllers with PHP 8.2+ native attributes:

```php
namespace App\Controller;

use App\Repository\CustomerRepository;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Attribute\Route;

#[Route('/api/v1/customers', name: 'api_customers_')]
class CustomerController extends AbstractController
{
    public function __construct(
        private readonly CustomerRepository $customerRepository
    ) {}

    #[Route('/{id}', name: 'show', methods: ['GET'])]
    public function show(int $id): JsonResponse
    {
        $customer = $this->customerRepository->find($id);

        if (!$customer) {
            return $this->json(['error' => 'Customer not found'], Response::HTTP_NOT_FOUND);
        }

        return $this->json($customer);
    }
}
```

### Doctrine ORM Entities & Attributes

Mapping database tables with native PHP attributes:

```php
namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;

#[ORM\Entity]
#[ORM\Table(name: 'orders')]
class Order
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 255)]
    #[Assert\NotBlank]
    private string $reference;

    #[ORM\Column(type: 'decimal', precision: 10, scale: 2)]
    #[Assert\Positive]
    private string $totalAmount;

    public function getId(): ?int { return $this->id; }
    public function getReference(): string { return $this->reference; }
    public function setReference(string $ref): self { $this->reference = $ref; return $this; }
    public function getTotalAmount(): string { return $this->totalAmount; }
    public function setTotalAmount(string $amount): self { $this->totalAmount = $amount; return $this; }
}
```

### Symfony Messenger for Async Processing

Decoupled message dispatching and handling:

```php
namespace App\Message;

class ProcessInvoiceMessage
{
    public function __construct(public readonly int $orderId) {}
}

// In Message Handler:
namespace App\MessageHandler;

use App\Message\ProcessInvoiceMessage;
use Symfony\Component\Messenger\Attribute\AsMessageHandler;

#[AsMessageHandler]
class ProcessInvoiceHandler
{
    public function __invoke(ProcessInvoiceMessage $message): void
    {
        // Handle background invoice generation
    }
}
```

## Common Patterns

### Doctrine Entity Repository with Custom DQL Query

**Problem**: Generic `find()` methods unable to execute efficient joined queries.

**Solution**:
Write custom repository query builders:

```php
namespace App\Repository;

use App\Entity\Product;
use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
use Doctrine\Persistence\ManagerRegistry;

class ProductRepository extends ServiceEntityRepository
{
    public function __construct(ManagerRegistry $registry)
    {
        parent::__construct($registry, Product::class);
    }

    public function findTopInStock(int $limit = 10): array
    {
        return $this->createQueryBuilder('p')
            ->andWhere('p.stock > 0')
            ->orderBy('p.createdAt', 'DESC')
            ->setMaxResults($limit)
            ->getQuery()
            ->getResult();
    }
}
```

## Best Practices

**Do**:

- Target Symfony 7+ using PHP 8.2+ native attributes for routing, entities, and validation.
- Utilize Symfony Messenger for all asynchronous and queue-based background processing.
- Run `bin/console lint:container` and `bin/console lint:yaml` in CI/CD pipelines.
- Configure Symfony Cache with Redis for high-traffic session and doctrine result caching.

**Don't**:

- Put business logic inside controllers; encapsulate workflows in domain services.
- Run `cache:clear` directly on active production traffic; warm up cache in a staging release directory.
- Disable CSRF protection on state-changing web form submissions.

## Troubleshooting

| Error                                                                 | Cause                                                       | Solution                                                              |
| :-------------------------------------------------------------------- | :---------------------------------------------------------- | :-------------------------------------------------------------------- |
| `ServiceNotFoundException: You have requested a non-existent service` | Service not autowired or missing in `config/services.yaml`. | Ensure class is in `src/` and check autowiring in `services.yaml`.    |
| `No route found for "GET /path"`                                      | Route attribute missing or cache stale.                     | Clear Symfony cache: `php bin/console cache:clear`.                   |
| `DriverException: An exception occurred in the driver: Access denied` | Database credentials incorrect in `.env` or `DATABASE_URL`. | Update `.env.local` with valid database host, username, and password. |

## References

- [Symfony Documentation](https://symfony.com/)


---
Source attribution: G1Joshi
Original project: https://github.com/G1Joshi/Agent-Skills/blob/6a74cf03a8a86dc7d993ead3091b41123dbd0181/skills/frameworks/symfony/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2026 G1Joshi

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: G1Joshi
Original project: https://github.com/G1Joshi/Agent-Skills/blob/6a74cf03a8a86dc7d993ead3091b41123dbd0181/skills/frameworks/symfony/SKILL.md
Attribution basis: Source repository record

Fields of work: Development & Engineering, Product Management
Roles: Backend Developer, Full-Stack Developer, Product Manager
Specialties: Backend, Cross Platform
Tools: Symfony
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: aa9cc0879b9c83d50cac47fe14596fbbf8303ff728762890cb981031bcad325b