Service Provider Laravel Package

Getting Started

Minimal Steps

1. Installation

   composer require container-interop/service-provider
   

   Add to composer.json under require (experimental, so ensure your team is aware).

2. First Use Case: Wrapping a Non-Laravel Container

   • Useful when integrating third-party libraries with PSR-11 containers (e.g., Symfony’s DependencyInjection).
   • Example: Convert a Symfony ContainerInterface to a PSR-11 container for Laravel’s DI:

     use ContainerInterop\ServiceProvider\ServiceProviderInterface;
     use Symfony\Component\DependencyInjection\ContainerInterface as SymfonyContainer;
     
     $symfonyContainer = new SymfonyContainer();
     $provider = new \ContainerInterop\ServiceProvider\SymfonyServiceProvider($symfonyContainer);
     $psr11Container = new \ContainerInterop\Container($provider);
     

3. Where to Look First

   • Documentation: PSR-11 and Container Interop.
   • Source: Focus on SymfonyServiceProvider and LaravelServiceProvider in the package’s src/ directory.
   • Laravel Integration: Check Illuminate/Container for compatibility notes (e.g., binding methods).

Implementation Patterns

Workflows

1. Bridging Containers

   • Use Case: Integrate a legacy Symfony app with Laravel’s DI.
   • Pattern:

     // In a Laravel service provider (e.g., AppServiceProvider)
     public function register()
     {
         $symfonyContainer = new SymfonyContainer();
         $provider = new \ContainerInterop\ServiceProvider\SymfonyServiceProvider($symfonyContainer);
         $this->app->bind('container.interop', function () use ($provider) {
             return new \ContainerInterop\Container($provider);
         });
     }
     

   • Resolution: Access via $app['container.interop']->get(MyService::class).

2. Extending Laravel’s Container

   • Use Case: Add PSR-11 compatibility to Laravel’s Container.
   • Pattern:

     $laravelProvider = new \ContainerInterop\ServiceProvider\LaravelServiceProvider($this->app);
     $psr11Container = new \ContainerInterop\Container($laravelProvider);
     

   • Note: Useful for libraries expecting PSR-11 but running in Laravel.

3. Service Provider Chaining

   • Use Case: Combine multiple providers (e.g., Symfony + custom).
   • Pattern:

     $container = new \ContainerInterop\Container();
     $container->addProvider(new SymfonyServiceProvider($symfonyContainer));
     $container->addProvider(new CustomServiceProvider());
     

Integration Tips

• Laravel Facades: Avoid direct PSR-11 usage in facades; wrap calls in service classes.
• Testing: Mock ServiceProviderInterface for unit tests:

  $mockProvider = $this->createMock(ServiceProviderInterface::class);
  $mockProvider->method('getService')->willReturn(new MyService());
  $container = new \ContainerInterop\Container($mockProvider);
  

• Performance: Cache PSR-11 containers if instantiated repeatedly (e.g., in a singleton binding).

Gotchas and Tips

Pitfalls

1. Experimental Status

   • Risk: API may change; avoid in production-critical paths.
   • Mitigation: Use behind feature flags or in non-core modules.

2. Laravel-Specific Quirks

   • Contextual Bindings: Laravel’s when()/needs() bindings aren’t directly translatable to PSR-11.
     • Workaround: Use LaravelServiceProvider with caution; prefer explicit bindings.
   • Singleton Scope: PSR-11 containers may not preserve Laravel’s singleton scope by default.
     • Fix: Manually bind singletons in the LaravelServiceProvider.

3. Circular Dependencies

   • Issue: PSR-11 containers may not handle Laravel’s circular dependency resolution.
   • Solution: Refactor to avoid circular references or use a hybrid approach (e.g., resolve via Laravel’s container when needed).

4. Namespace Collisions

   • Problem: Third-party PSR-11 services might clash with Laravel’s autoloading.
   • Fix: Use fully qualified class names or aliases in bindings.

Debugging

• Service Not Found: Verify the provider is registered and the service is bound in the underlying container (e.g., Symfony/Laravel).

  // Debug Laravel bindings
  $this->app->bindings;
  

• Type Hints: Ensure PSR-11 services implement expected interfaces (e.g., Psr\Container\ContainerInterface).

Extension Points

1. Custom Providers
   • Implement ServiceProviderInterface for non-Symfony/Laravel containers:

     class MyCustomProvider implements ServiceProviderInterface {
         public function getService($id) {
             return new $id(); // Simplified example
         }
     }
     

2. Middleware Integration
   • Use PSR-15 middleware with Laravel via PSR-11:

     $container->get(Psr15MiddlewareDispatcher::class)->dispatch(
         $request,
         $response
     );
     

3. Event Dispatching
   • Bridge Laravel events to PSR-11 containers by binding an event dispatcher:

     $container->set(
         Symfony\Contracts\EventDispatcher\EventDispatcherInterface::class,
         $this->app->make(SymfonyEventDispatcher::class)
     );