README

code-distortion/di-caller is a PHP package that instantiates classes, and calls callables / callbacks / hooks using dependency injection to resolve their parameters.

I built this to use in my own packages, where the caller wants to instantiate classes or pass callbacks, and the paramaters they actually need aren't know ahead of time. This package lets you specify the parameters you want to provide, and it resolves which ones are needed at call-time.

It isn't a Dependency Injection Container like those used in frameworks. Each callable is dealt with individually.

Installation
Usage
- Instantiating Classes
- Running Callables
Registering Parameters
Exceptions
Error Checking
- Checking When Instantiating Classes
- Checking When Running Callables

Installation

Install the package via composer:

composer require code-distortion/di-caller

Usage

There are three steps to using this package:

Create a DICaller instance and pass the class you'd like to instantiate or callable you'd like to call,
Register the parameters you'd like to make available,
Instantiate the class using ->instantiate() or execute the callable using ->call().

DICaller will match the parameters you've registered to the constructor or callable signature.

Instantiating Classes

Instantiate classes by passing the class FQCN to DICaller, and calling ->instantiate():

namespace MyApp;

class User
{
    public function __construct(
        private string $firstName,
        private string $lastName,
    ) {}
}

use CodeDistortion\DICaller\DICaller;
use MyApp\User;

$result = DICaller::new(User::class)
    ->registerByName('firstName', 'Bob')
    ->registerByName('lastName', 'Smith')
    ->instantiate(); // new User instance

Running Callables

Call a callable by passing it to DICaller, and running ->call():

use CodeDistortion\DICaller\DICaller;
use MyApp\User;

$callable = fn(User $user) => "hello {$user->firstName}";

$result = DICaller::new($callable)
    ->registerType(new User('Bob', 'Smith'))
    ->call(); // 'hello Bob'

Registering Parameters

Registering Parameters by Type

You can register parameters by type, which supports class-type and variable type (integer, string, etc).

In this example, more parameters are registered than are actually needed. Only the necessary ones are used.

use CodeDistortion\DICaller\DICaller;
use MyApp\Request;
use MyApp\ShoppingCart;
use MyApp\User;

$callable = fn(Request $request, User $user, float $duration)
    => "$user->name ({$request->getIp()}) - $duration seconds";

$user = new User('Bob', 'Smith');
$request = new Request(…);
$shoppingCart = new ShoppingCart(…);
$someId = 10;
$duration = 4.55;

$result = DICaller::new($callable)
    ->registerByType($user)         // <<<
    ->registerByType($request)      // <<<
    ->registerByType($shoppingCart) // <<<
    ->registerByType($someId)       // <<<
    ->registerByType($duration)     // <<<
    ->call(); // 'Bob (192.168.1.1) - 4.55 seconds'

For finer control, you can also specify their type explicitly (for class-types only):

use CodeDistortion\DICaller\DICaller;
use MyApp\Request;
use MyApp\ShoppingCart;
use MyApp\User;

$callable = fn(Request $request, User $user, float $duration)
    => "$user->name ({$request->getIp()}) - $duration seconds";

$user = new User('Bob', 'Smith');
$request = new Request(…);
$shoppingCart = new ShoppingCart(…);
$someId = 10;
$duration = 4.55;

$result = DICaller::new($callable)
    ->registerByType($user, User::class)                 // <<<
    ->registerByType($request, Request::class)           // <<<
    ->registerByType($shoppingCart, ShoppingCart::class) // <<<
    ->registerByType($someId)
    ->registerByType($duration)
    ->call(); // 'Bob (192.168.1.1) - 4.55 seconds'

Registering Parameters by Name

You can register parameters by name:

use CodeDistortion\DICaller\DICaller;

$callable = fn($param1, $param2) => "$param1 $param2";

$result = DICaller::new($callable)
    ->registerByName('param1', 'hello') // <<<
    ->registerByName('param2', 'world') // <<<
    ->call(); // 'hello world'

Registering Parameters by Position

You can register parameters by position (starting from 0):

use CodeDistortion\DICaller\DICaller;

$callable = fn($param1, $param2) => "$param1 $param2";

$result = DICaller::new($callable)
    ->registerByPosition(0, 'hello') // <<<
    ->registerByPosition(1, 'world') // <<<
    ->call(); // 'hello world'

Union, Intersection and Variadic Types

Union types are supported.

In this example, the parameter picked must be either an int or a float.

use CodeDistortion\DICaller\DICaller;

$callable = fn(int|float $param1) => $param1; // <<<

$result = DICaller::new($callable)
    ->registerByType(1.1) // <<<
    ->call(); // 1.1

Note: Union types might not be processed in the same order as they're written in the signature, as DICaller uses Reflection which may alter the order.

Intersection types are supported.

In this example, the parameter must be both a ParentClass and a ChildClass.

use CodeDistortion\DICaller\DICaller;

$callable = fn(ParentClass&ChildClass $param1) => $param1; // <<<

$result = DICaller::new($callable)
    ->registerByType(new ChildClass()) // <<<
    ->call(); // ChildClass

Variadic parameters are supported, but are treated like normal parameters.

use CodeDistortion\DICaller\DICaller;

$callable = fn(int $param1, int ...$param2) => func_get_args(); // <<<

$result = DICaller::new($callable)
    ->registerByName('param1', 1)
    ->registerByName('param2', 2)
    ->call(); // [1, 2]

Exceptions

If the class can't be instantiated, a DICallerInstantiationException is thrown when ->instantiate() is called:

use CodeDistortion\DICaller\DICaller;
use MyApp\User;

$user = DICaller::new(User::class)->instantiate();
// throws DICallerInstantiationException - when there are unresolved parameters

If a callable can't be called, a DICallerCallableException is thrown when ->call() is run:

use CodeDistortion\DICaller\DICaller;

$callable = fn($param1, $param2) => "$param1 $param2";

$result = DICaller::new($callable)->call(); // throws DICallerCallableException

Error Checking

Checking When Instantiating Classes

Before calling ->instantiate(), you can check to see if the class can actually be instantiated using ->canInstantiate().

If the parameters satisfy the needs of the constructor, ->canInstantiate() will return true. Otherwise, it will return false.

use CodeDistortion\DICaller\DICaller;
use MyApp\User;

$instantiator = DICaller::new(User::class)
    ->registerByName('middleName', 'John');
$user = $instantiator->canInstantiate() // false - because $firstName and $lastName are unresolved
    ? $instantiator->instantiate()
    : null;

And you can check & instantiate in one step using ->instantiateIfPossible():

use CodeDistortion\DICaller\DICaller;
use MyApp\User;

$user = DICaller::new(User::class)
    ->registerByName('middleName', 'John')
    ->instantiateIfPossible();
// null - because $firstName and $lastName are unresolved

This will return the object, or null if it can't be instantiated.

Checking When Running Callables

Before calling ->call(), you can check that the callable is actually callable, and the parameters resolve properly using ->canCall():

use CodeDistortion\DICaller\DICaller;

$callable = fn($param1, $param2) => "$param1 $param2";

$caller = DICaller::new($callable)
    ->registerByName('param3', 'something');
if ($caller->canCall()) { // false - because $param1 and $param2 are unresolved
    $result = $caller->call();
}

And you can check & call it in one step using ->callIfPossible():

use CodeDistortion\DICaller\DICaller;

$callable = fn($param1, $param2) => "$param1 $param2";

$result = DICaller::new($callable)
    ->registerByName('param3', 'something')
    ->callIfPossible(); // null - because $param1 and $param2 are unresolved

Note: This will return null when the call isn't possible, which isn't distinguishable from a successful call that returns null on purpose.

Testing This Package

Clone this package: git clone https://github.com/code-distortion/di-caller.git .
Run composer install to install dependencies
Run the tests: composer test

Changelog

Please see CHANGELOG for more information on what has changed recently.

SemVer

This library uses SemVer 2.0.0 versioning. This means that changes to X indicate a breaking change: 0.0.X, 0.X.y, X.y.z. When this library changes to version 1.0.0, 2.0.0 and so forth, it doesn't indicate that it's necessarily a notable release, it simply indicates that the changes were breaking.

Treeware

This package is Treeware. If you use it in production, then we ask that you buy the world a tree to thank us for our work. By contributing to the Treeware forest you’ll be creating employment for local families and restoring wildlife habitats.

Contributing

Please see CONTRIBUTING for details.

Code of Conduct

Please see CODE_OF_CONDUCT for details.

Security

If you discover any security related issues, please email tim@code-distortion.net instead of using the issue tracker.

Credits

Tim Chandler

License

The MIT License (MIT). Please see License File for more information.

code-distortion / di-caller

Maintainers

Details