7-CONTEXT_API.md

Context API

The Context API allows us to replace on dependency with another, based on a contextual circumstance. Basically, it allows a program to say When using "A", and "A" needs "B", give "C".

How this translates:

• If we’re resolving a dependency
• And we know who asked for it
• And there’s a contextual rule for that pair
• Use the override instead

We can see it in action by thinking of it programmtically using a context tree below:

when → ReportService
  └─ needs → LoggerInterface
  └─ give → ReportLogger

In order to add contextual rules inside a Service Provider, we simply have to call the Context API from that Provider from within the register() method. The Context System provides a Fluent API with descriptive methods that are to be chained together, in order to create the required contextual rules.

use FrameworkFactory\Contracts\Providers\ServiceProvider;
use App\Services\ReportService;
use App\Loggers\ReportLogger;
use Psr\Log\LoggerInterface;

class ReportServiceProvider extends ServiceProvider
{
    public function register()
    {
        // first we want to bind the service to the container
        $this->bind(ReportService::class, fn() => new ReportService());
        
        // now we can utilize the Context API
        $this->when(ReportService::class)
             ->needs(LoggerInterface::class)
             ->give(ReportLogger::class)
    }
}

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• See Also: Service Providers
• See Also: Lifecycle Hooks
• See Also: Accessors