Learn How to Implement a PHP Strategy Pattern for Contests with the Package Strategy Pattern Example: Add a competition strategy to model classes

This code contains a startegy pattern implemented for a contest management system.

It is the implementation of the backend of a competition management system, where the administrators can create different predefined competitions, and the backend logic and also the UI will differ from strategy to strategy.

The App\Models\Contest has a strategy property stored in the database, and set by the Administrators on contest creation, which holds the key of the applied strategy. This adds the functionality and UI logic to the contest.

The relevant part of the Contest model is as follows:

<?php

namespace App\Models;

use App\Extensions\Contests\ContestStrategy;
use App\Extensions\Contests\ContestStrategyMap;
use Illuminate\Database\Eloquent\Model;

class Contest extends Model
{
    public function getStrategy(): ContestStrategy
    {
        $map = ContestStrategyMap::create();
        return $map->getStrategyForKey($this->strategy, $this);
    }
}

The details of the functionalities of each of the strategy are stored in the App/Extensions/Contests/Strategies/*/Features folders in various classes like ValidationRules, ViewSection, etc., and loaded through the code as follows:

$validationRules = $contest->getStrategy()->executeFeature('validation-rules');

// or

$contestViewSection = $contest->getStrategy()->executeFeature('view-section');
$listElement = $contestViewSection?->getSectionByKey('list-element', compact($product));

Also, the NoFeatureImplementedForStrategyException it is handled in app/Exceptions/Handler.php.