Autowiring

Autowiring is a powerful feature that automates the process of resolving and injecting dependencies for your services. Instead of manually specifying every dependency in your configuration file, autowiring lets the container analyze your classes and figure out the dependencies based on type hints in constructor arguments or setter methods.

How It Works#

1. Type Analysis: When autowiring is enabled, the container inspects the constructor (or setter methods if you are using setter injection) of your classes.
2. Dependency Resolution: For each constructor parameter or setter method, the container looks for a registered service that matches the type hint.
3. Injection: If a matching service is found, the container automatically injects it into the object when it’s created.

Example

// container.php

return  [
    PDO::class => /* definition */,
];

// OrderRepository.php
class OrderRepository {
    public function __construct(PDO $pdo) { /* ... */ }
}

With autowiring enabled (default behavior), you wouldn’t need to explicitly define the OrderRepository in your configuration file. The container would automatically detect that the OrderRepository constructor requires a PDO instance and inject it.

Caveats and Considerations

• Ambiguity: Autowiring can fail if there are multiple services of the same type and the container can’t determine which one to inject. In such cases, you’ll need to provide explicit configuration to resolve the ambiguity.
• Performance: While autowiring is generally fast, it might introduce a slight overhead compared to explicit configuration. If you’re dealing with highly performance-critical code, you might consider compiling container and disabling autowiring.

Disabling Autowiring#

By default, autowiring is enabled in the Norvica DI Container. You can disable it using the Configurator class:

// container.php
use Norvica\Container\Configurator;

$configurator = new Configurator();
$configurator->autowiring(false); // Disable autowiring
// ... rest of the configuration