What Are Laravel Contracts

In Laravel, Contracts are a set of interfaces that define the core services provided by the framework. These are found in the Illuminate\Contracts namespace.

🔹 What Are Laravel Contracts?

Contracts are like agreements or blueprints. They specify the methods a class must implement. Laravel uses these contracts to define the behavior of various components like:

• Cache
• Queue
• Mail
• Events
• Filesystem
• Authentication
• Logging, etc.

🔹 Why Use Contracts?

• Loose coupling: You can easily swap implementations without changing the code that uses them.
• Testing: Makes it easier to mock dependencies.
• Cleaner code: Encourages following the SOLID principles, especially the Dependency Inversion Principle.

🔹 Example: Cache Contract

Laravel’s cache system uses the Illuminate\Contracts\Cache\Repository contract.

Interface (Contract):

use Illuminate\Contracts\Cache\Repository;

class MyService {
    protected $cache;

    public function __construct(Repository $cache) {
        $this->cache = $cache;
    }

    public function getData() {
        return $this->cache->get('key');
    }
}

Here, Laravel will inject any class that implements the Repository contract. The default is Illuminate\Cache\CacheManager.

🔹 Where Are Contracts Defined?

All contracts live in the Illuminate\Contracts namespace.

Example path:

vendor/laravel/framework/src/Illuminate/Contracts

🔹 Commonly Used Contracts

🔹 Binding Contracts to Implementations

Laravel uses the service container to bind interfaces to concrete classes.

Example from AppServiceProvider:

use Illuminate\Contracts\Cache\Repository;
use App\Services\CustomCacheService;

public function register()
{
    $this->app->bind(Repository::class, CustomCacheService::class);
}

🔹 Summary

• Contracts are interfaces that define expected functionality.
• They promote flexibility, testability, and clean architecture.
• Laravel provides concrete implementations and binds them automatically.
• You can replace default services by binding your own implementations.