Guides

Using Services & Dependency Injection

Intermediate~8 min

Request services via contracts. The container resolves dependencies automatically — you declare, we inject.

Declaring Services

List the services your module needs in the "services" array of module.json. Available services include: settings, logger, cache, http, events, and scheduler.

module.json (partial)
{
  "slug": "analytics",
  "services": ["settings", "logger", "cache", "http"]
}

Constructor Injection

The container matches service names to their contract interfaces and injects them into your constructor. Type-hint the interface — the container resolves the implementation.

class-module.php
<?php

use Meteorack\SDK\Contracts\CacheInterface;
use Meteorack\SDK\Contracts\HttpInterface;

class Analytics_Module implements ModuleInterface {

    public function __construct(
        private readonly CacheInterface $cache,
        private readonly HttpInterface $http,
    ) {}

    public function boot(): void {
        add_action('wp_footer', [$this, 'track']);
    }

    public function track(): void {
        $key = 'pageview:' . get_the_ID();

        // Cache prevents duplicate tracking
        if ($this->cache->has($key)) {
            return;
        }

        $this->http->post('/api/track', [
            'page_id' => get_the_ID(),
            'timestamp' => time(),
        ]);

        $this->cache->set($key, true, 300);
    }
}

Available Contracts

Every service has a corresponding contract interface in the SDK. Your module depends on the interface, never on the concrete implementation. This makes testing trivial — mock the interface, test your logic.

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