A dependency injection class based on Pimple

4.0 2014-10-14 21:17 UTC


A dependency injection class based on Pimple 3

Build Status

Author: Emmanuel Antico
Last Modification: 2014/10/14
Version: 4.0

Installation ------------
Installation is made via composer. Add the following lines to the composer.json file in your project.
    "require": {
		"injector/injector": "4.0.*"

Dependencies ------------
Injector requires the following packages to be installed:
How to use ------------
Injector is a dependency injection library that uses the *Pimple\Container* class to initialize a set of properties within an instance. This is done by adding the appropiate annotations to the class declaration.
>Step 1: Create a Provider

A provider is a class that implements the Pimple\ServiceProviderInterface interface. This class sets a number of services (and parameters) inside a container.

namespace Acme\Providers;

use Pimple\Container;
use Pimple\ServiceProviderInterface;
use Acme\Services\Logger;
use Acme\Services\MySQLConnection;

class MainProvider implements ServiceProviderInterface {
    public function register(Container $container) {
        //add some services
        $container['logger'] = function ($c) {
            return new Logger();
        $container['conn'] = function ($c) {
            return new MySQLConnection('usr', 'psw');
        $container['environment'] = 'development';

>Step 2: Configure your class

In order to indicate a class provider we add the @Provider annotation followed by the provider class name. Dependencies can now be injected through the @Inject annotation. Notice that the syntax used for injecting contructor arguments differs a bit from the others.

namespace Acme\Components;

 * @Provider Acme\Providers\MainProvider
class MyComponent {
    private $name;
    private $env;    
     * @Inject logger
    private $logger;
     * @Inject conn
    private $connection;
     * @Inject($env) environment
    public function __construct($name, $env) {
        $this->name = $name;
        $this->env = $env;
    public function getEnvironment() {
        return $this->env;

    public function getName() {
        return $this->name;
    public function getLogger() {
        return $this->logger;
    public function getConnection() {
        return $this->connection;

>Step 3: Create an instance

Instances are created through the create static method in the Injector\Injector class. Additional arguments could be added as an array.

use Injector\Injector;
use Acme\Services\SQLiteConnection;

$component = Injector::create('Acme\Components\MyComponent', ['My Component']);
$component->getEnvironment(); //returns 'development'
$component->getName(); //returns 'My Component'
$component->getLogger()->debug('Component initialized');

//overriding a constructor parameter
$component = Injector::create('Acme\Components\MyComponent', ['My Component', 'production']);
$component->getEnvironment(); //returns 'production'

//filtering dependencies
$component = Injector::create('Acme\Components\MyComponent', ['My Component'], ['logger']);
$component->getLogger(); //Logger
$component->getConnection(); // NULL

//overriding dependencies
$component = Injector::create('Acme\Components\MyComponent', ['My Component'], null, ['conn' => new SQLiteConnection('file.db')]);
$component->getConnection(); // SQLiteConnection

>Step 3 (alt): Inject dependencies

You could also inject dependencies directly through the inject method using a custom made container.

use Injector\Injector;

//create container
$container = new Pimple\Container;
$provider = new Acme\Providers\MainProvider();

//inject dependencies
$component = new CustomComponent();
Injector::inject($component, $container);
$component->getLogger()->debug('Component initialized');


Subclasses can extend the same set of providers from its parent class by adding the @ExtendInject annotation.


 * Set class providers:
 * @Provider MainProvider
 * @Provider CustomProvider
class A {


 * Obtain providers from parent class:
 * @ExtendInject
class B extends A {

License -------
This code is licensed under the BSD 2-Clause license.