Principi di Codice Pulito per XOOPS

Panoramica

Il codice pulito è codice facile da leggere, comprendere e mantenere. Questa guida copre i principi del codice pulito specificamente applicati allo sviluppo di moduli XOOPS.

Principi Fondamentali

mindmap
  root((Clean Code))
    Readability
      Meaningful Names
      Small Functions
      Comments When Needed
    Simplicity
      Single Responsibility
      DRY Principle
      KISS Principle
    Maintainability
      Consistent Style
      Error Handling
      Testing

Nomi Significativi

Variabili

// Bad
$d = new DateTime();
$u = $memberHandler->getUser($id);
$arr = [];

// Good
$createdDate = new DateTime();
$currentUser = $memberHandler->getUser($userId);
$publishedArticles = [];

Funzioni

// Bad
function process($data) { ... }
function handle($item) { ... }
function doStuff($x, $y) { ... }

// Good
function publishArticle(Article $article): void { ... }
function calculateTotalPrice(array $items): float { ... }
function sendNotificationEmail(User $user, string $subject): bool { ... }

Classi

// Bad
class Manager { ... }
class Helper { ... }
class Utils { ... }

// Good
class ArticleRepository { ... }
class NotificationService { ... }
class PermissionChecker { ... }

Funzioni Piccole

Single Responsibility

// Bad - does too many things
function processArticle($data) {
    // Validate
    if (empty($data['title'])) {
        throw new Exception('Title required');
    }
    // Save
    $article = new Article();
    $article->setTitle($data['title']);
    $this->repository->save($article);
    // Notify
    $this->mailer->send($article->getAuthor(), 'Article published');
    // Log
    $this->logger->info('Article created');
    return $article;
}

// Good - each function does one thing
function validateArticleData(array $data): void
{
    if (empty($data['title'])) {
        throw new ValidationException('Title required');
    }
}

function createArticle(array $data): Article
{
    $this->validateArticleData($data);
    return Article::create($data['title'], $data['content']);
}

function publishArticle(Article $article): void
{
    $this->repository->save($article);
    $this->notifyAuthor($article);
    $this->logArticleCreation($article);
}

Lunghezza della Funzione

Mantieni le funzioni brevi - idealmente sotto 20 righe:

// Good - focused function
public function getPublishedArticles(int $limit = 10): array
{
    $criteria = new CriteriaCompo();
    $criteria->add(new Criteria('status', 'published'));
    $criteria->setSort('published_at');
    $criteria->setOrder('DESC');
    $criteria->setLimit($limit);

    return $this->repository->getObjects($criteria);
}

Principio DRY (Non Ripeterti)

Estrai Codice Comune

// Bad - repeated code
function getActiveUsers() {
    $criteria = new CriteriaCompo();
    $criteria->add(new Criteria('level', 0, '>'));
    $criteria->setSort('uname');
    return $this->userHandler->getObjects($criteria);
}

function getActiveAdmins() {
    $criteria = new CriteriaCompo();
    $criteria->add(new Criteria('level', 0, '>'));
    $criteria->add(new Criteria('is_admin', 1));
    $criteria->setSort('uname');
    return $this->userHandler->getObjects($criteria);
}

// Good - shared logic extracted
function getUsers(CriteriaCompo $criteria): array
{
    $criteria->add(new Criteria('level', 0, '>'));
    $criteria->setSort('uname');
    return $this->userHandler->getObjects($criteria);
}

function getActiveUsers(): array
{
    return $this->getUsers(new CriteriaCompo());
}

function getActiveAdmins(): array
{
    $criteria = new CriteriaCompo();
    $criteria->add(new Criteria('is_admin', 1));
    return $this->getUsers($criteria);
}

Gestione degli Errori

Usa le Eccezioni Correttamente

// Bad - generic exceptions
throw new Exception('Error');

// Good - specific exceptions
throw new ArticleNotFoundException($articleId);
throw new PermissionDeniedException('Cannot edit article');
throw new ValidationException(['title' => 'Title is required']);

Gestisci gli Errori Correttamente

public function findArticle(string $id): ?Article
{
    try {
        return $this->repository->findById($id);
    } catch (DatabaseException $e) {
        $this->logger->error('Database error finding article', [
            'id' => $id,
            'error' => $e->getMessage()
        ]);
        throw new ServiceException('Unable to retrieve article', 0, $e);
    }
}

Commenti

Quando Commentare

// Bad - obvious comment
// Increment counter
$counter++;

// Good - explains why, not what
// Cache for 1 hour to reduce database load during peak traffic
$cache->set($key, $data, 3600);

// Good - documents complex algorithm
/**
 * Calculate article relevance score using TF-IDF algorithm.
 * Higher scores indicate better match with search terms.
 */
function calculateRelevanceScore(Article $article, array $terms): float
{
    // ...
}

Organizzazione del Codice

Struttura della Classe

class ArticleService
{
    // 1. Constants
    private const MAX_TITLE_LENGTH = 255;

    // 2. Properties
    private ArticleRepository $repository;
    private EventDispatcher $events;

    // 3. Constructor
    public function __construct(
        ArticleRepository $repository,
        EventDispatcher $events
    ) {
        $this->repository = $repository;
        $this->events = $events;
    }

    // 4. Public methods
    public function publish(Article $article): void { ... }
    public function archive(Article $article): void { ... }

    // 5. Private methods
    private function validateForPublication(Article $article): void { ... }
}

Checklist di Codice Pulito

• I nomi sono significativi e pronunciabili
• Le funzioni fanno una cosa sola
• Le funzioni sono piccole (< 20 righe)
• Nessun codice duplicato
• Adeguata gestione degli errori con eccezioni specifiche
• I commenti spiegano “perché”, non “cosa”
• Formattazione e stile coerente
• Nessun numero magico o stringa
• Le dipendenze sono iniettate, non create

Documentazione Correlata

• Code Organization
• Error Handling
• Testing Best Practices
• PHP Standards