name: php-best-practices
description: Write PHP following PSR coding standards, SOLID principles, and code-quality guidelines. Use for PHP style, design, refactoring, naming, and guard clauses—not Composer/PSR-4 project configuration.
metadata:
triggers:
files:
- '**/*.php'
keywords:
- 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 namespace. Run PHP CS Fixer with 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 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 controller output.
References
Canonical response anchors
When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:
- SRP:,single responsibility,one responsibility
- PascalCase
- no else after return,else after a return,reduce nesting,reducing nesting,deeply nested
- same-line opening braces,opening braces on same line,Braces on the same line