php-best-practices

name	php-best-practices
description	PHP best practices, PSR standards, and code quality guidelines. Use when writing PHP following PSR standards, SOLID principles, or improving code quality. (triggers: **/*.php, psr-12, camelCase, PascalCase, dry, solid)

PHP Best Practices

Priority: P1 (HIGH)

Structure

src/
├── {Domain}/             # e.g., Services, Repositories
└── Helpers/              # Pure functions/Traits

Implementation Guidelines

Coding Style (PSR Standards)

• PSR-12: Enforce 4-space indentation and opening braces on same line for functions/methods.
• Organization: One class per file; use statements follow the namespace. Run PHP CS Fixer with the PSR-12 preset.
• Naming Conventions: Use PascalCase (UserService) for classes, camelCase (getUserById) for methods/variables, and SNAKE_CASE (MAX_RETRIES) for class constants.

SOLID Principles in PHP

• SRP: Single Responsibility Principle — extract each into its own focused class; keep classes under ~200 lines.
• Dependency Inversion: inject via constructor with interface type-hints. Inject dependencies via constructor for testability. Favor composition over deep inheritance chains.
• Separation of Concerns: Use Interfaces for decoupling integrations and logic.

Logic & Performance

• Guard Clauses: Return early for error conditions (e.g., if (!$user) return null); no else after return to reduce nesting depth.
• Traits: Define trait HasTimestamps (e.g., use HasTimestamps) for cross-cutting behavior. Keep traits focused and lightweight.
• Helper Functions: Avoid global-namespace logic; organize in classes.

Anti-Patterns

• No monolithic classes: Each class has one responsibility (SRP).
• No hardcoded magic numbers: Define as named class constants.
• No deep nesting: Use guard clauses to return early.
• No echo in services: Return data; let the controller output.

References

• Clean Code Patterns