Dependency Injection Sample Code - 2023

Container.php

<?php

class Container implements Psr\Container\ContainerInterface
{
    protected $s = [];
    function __set($k, $c) { $this->s[$k]=$c; }
    function __get($k) { return $this->s[$k]($this); }
    function get($k) { return $this->s[$k]($this); }
    function has($k) { return isset($s[$k]); }
}

FizzBuzz.php

<?php

class Fizz { public function __toString() { return 'Fizz'; } }
class Buzz { public function __toString() { return 'Buzz'; } }

class FizzBuzz
{
    public function __construct(private Fizz $fizz, private Buzz $buzz)
    {
    }

    public function __invoke(int $i): string
    {
        if (!($i % 15)) return $this->fizz . $this->buzz;
        if (!($i % 3)) return (string) $this->fizz;
        if (!($i % 5)) return (string) $this->buzz;
        return (string) $i;
    }
}

phpdi-basic.php

<?php

// composer require php-di/php-di

use function DI\create;

class NeedsALogger
{
    public function __construct(private Logger $logger)
    {
    }
}

class Logger {}

$c = new \DI\Container();
$c->set('LoggerInterface', create('Logger'));

// returns a NeedsALogger
var_dump($c->get('NeedsALogger'));

phpdi-compiled.php

<?php

// composer require php-di/php-di

use function DI\autowire;

class NeedsALogger
{
    public function __construct(private Logger $logger)
    {
    }
}

class Logger {}

$builder = new \DI\ContainerBuilder();
$builder->enableCompilation('/tmp');
$builder->addDefinitions([
    'LoggerInterface' => autowire('Logger'),
    'NeedsALogger' => autowire()
]);

$c = $builder->build();

var_dump($c->get('NeedsALogger'));

run-fizzbuzz-phpdi.php

<?php

// composer require php-di/php-di

require 'FizzBuzz.php';

$c = new \DI\Container();

foreach (range(1, 15) as $i) {
    echo $c->get('fizzBuzz')($i) . "\n";
}

run-fizzbuzz.php

<?php

// composer require psr/container

require 'Container.php';
require 'FizzBuzz.php';

$c = new Container;

$c->fizz = fn () => new Fizz;
$c->buzz = fn () => new Buzz;

$c->fizzBuzz = fn ($c) => new FizzBuzz($c->fizz, $c->buzz);

foreach (range(1, 15) as $i) {
    echo $c->get('fizzBuzz')($i) . "\n";
}