CodeIgniter Best Practices

CodeIgniter Best Practices (CodeIgniter 4)

Following best practices helps you build clean, secure, scalable, and maintainable CodeIgniter applications. Below is a complete, practical guide you can follow in real projects.

1. Follow MVC Properly

Controller = coordinator only

• Handle request

• Call models

• Return views / responses

❌ Avoid:

• Business logic in controllers

• Database queries in views

✅ Example:

// Controller
$data['users'] = $this->userModel->getActiveUsers();
return view('users/index', $data);

2. Use Models for All Database Logic

• Use Model classes

• Use Query Builder

• Define $allowedFields

class UserModel extends Model
{
    protected $table = 'users';
    protected $allowedFields = ['name', 'email'];
}

3. Use Environment-Based Configuration

• .env for environment variables

• Different configs for dev / prod

CI_ENVIRONMENT = production

❌ Never hardcode credentials

4. Validation Is Mandatory

Always validate:

• Form inputs

• API requests

if (! $this->validate($rules)) {
    return redirect()->back()->withInput();
}

5. Escape Output (XSS Protection)

Always escape in views:

<?= esc($title) ?>

Never trust user data.

6. Use Filters Instead of Manual Checks

• Authentication

• Authorization

• HTTPS enforcement

$routes->group('admin', ['filter' => 'auth'], function($routes) {});

Cleaner & reusable.

7. Use Resource Controllers for APIs

• Follow REST conventions

• Return proper HTTP status codes

return $this->respondCreated($data);

8. Enable CSRF Protection

Globally enable CSRF:

'csrf'

Use:

<?= csrf_field() ?>

9. Handle Errors Gracefully

• Custom error pages

• Use logging

• Never show errors in production

Logs:

writable/logs/

10. Optimize Performance

• Enable caching

• Optimize queries

• Use indexes

• Enable OPcache

$routes->get('home', 'Home::index', ['cache' => 60]);

11. Secure File Uploads

• Validate file type & size

• Rename files

• Store outside public/

'file' => 'uploaded[file]|ext_in[file,jpg,png]'

12. Use Helpers & Libraries Wisely

• Load only when needed

• Avoid global autoload of everything

13. Disable Auto Routing

Explicit routes are safer:

$routes->setAutoRoute(false);

14. Keep Controllers Thin

If logic grows:

• Move to Services

• Use Libraries

app/Services/

15. Version Control Best Practices

• Use Git

• .gitignore .env, writable/

• Meaningful commit messages

16. Naming Conventions

• Controllers: UserController

• Models: UserModel

• Methods: camelCase()

• Tables: snake_case

17. Use Official Packages

• CodeIgniter Shield → Authentication

• Myth/Auth (legacy)

18. Regular Maintenance

• Update CodeIgniter

• Review logs

• Test backups

19. Testing

• Unit tests

• Feature tests

• Test APIs

php spark test

20. Documentation

• Comment complex logic

• Maintain README

• Document APIs

Best Practices Checklist

✔ Proper MVC
✔ Validation everywhere
✔ Escaped output
✔ Secure sessions
✔ Explicit routes
✔ Caching enabled
✔ Production environment

Final Thoughts

CodeIgniter shines when you:

• Keep code simple

• Follow framework conventions

• Prioritize security & performance