Constructor Bindings

When #[Inject] attribute cannot be applied to the target constructor or setter method because it is a third party class, Or you simply don’t like to use annotations. Constructor Binding provide the solution to this problem. By calling your target constructor explicitly, you don’t need reflection and its associated pitfalls. But there are limitations of that approach: manually constructed instances do not participate in AOP.

To address this, Ray.Di has toConstructor bindings.

$this->bind($interfaceName)
    ->toConstructor(
        $className,       // Class name
        $name,            // Qualifier
        $injectionPoint,  // Setter injection
        $postConstruct    // Initialize method
    );

(new InjectionPoints) 
    ->addMethod('setGuzzle')                 // Setter injection method name
    ->addOptionalMethod('setOptionalToken'); // Optional setter injection method name

Parameter

class_name

Class name

name

Parameter name binding.

If you want to add an identifier to the argument, specify an array with the variable name as the key and the value as the name of the identifier.

[
	[$param_name1 => $binding_name1],
	...
]

The following string formats are also supported

'param_name1=binding_name1&...'

setter_injection

Specify the method name ($methodName) and qualifier ($named) of the setter injector in the InjectionPoints object.

(new InjectionPoints)
	->addMethod($methodName1)
	->addMethod($methodName2, $named)
    ->addOptionalMethod($methodName, $named);

postCosntruct

Ray.Di will invoke that constructor and setter method to satisfy the binding and invoke in $postCosntruct method after all dependencies are injected.

PDO Example

Here is the example for the native PDO class.

public PDO::__construct ( string $dsn [, string $username [, string $password [, array $options ]]] )

$this->bind(\PDO::class)->toConstructor(
  \PDO::class,
  [
    'dsn' => 'pdo_dsn',
    'username' => 'pdo_username',
    'password' => 'pdo_password'
  ]
)->in(Scope::SINGLETON);
$this->bind()->annotatedWith('pdo_dsn')->toInstance($dsn);
$this->bind()->annotatedWith('pdo_username')->toInstance(getenv('db_user'));
$this->bind()->annotatedWith('pdo_password')->toInstance(getenv('db_password'));

Since no argument of PDO has a type, it binds with the Name Binding of the second argument of the toConstructor() method. In the above example, the variable username is given the identifier pdo_username, and toInstance binds the value of the environment variable.