My Appication Layer Keeps Breaking!

Code and style patterns and anti-patterns that keep code clean and easier to maintain.

Transcript

1. My application layer keeps breaking! A presentation by @stephenfrank 0
2. Spoiler alert! It still does.
3. aka Advice to myself What advice would I give myself two years ago that would help me to write code that doesn’t break and is easier to maintain.
4. Steve! Forget the things you’ve learned from CodeIgniter!
5. Use auto-loaders require ("vendor/autoload.php"); // None of this malarky $this->load->library('article'); $this->article->foo(); // Clean and simple loading $article = new Article; // ...or a Service Locator $article = App::make('article');
6. Pseudo-singleton patterns and “god” objects class Reports { function report_generator() { $this->load->library('table'); $this->table->set_heading('Name', 'Color', 'Size'); $this->table->add_row('Fred', 'Blue', 'Small'); echo $this->table->generate(); $this->table->clear(); // LUL WAT? $this->table->set_heading('Name', 'Color', 'Size'); $this->table->add_row('Fred', 'Blue', 'Small'); echo $this->table->generate(); } }
7. class Reports { function report_generator() { $table = new Table; $table->setHeading('Name', 'Color', 'Size'); $table->addRow('Fred', 'Blue', 'Small'); echo $table->generate(); $table = new Table; $table->setHeading('Name', 'Color', 'Size'); $table->addRow('Fred', 'Blue', 'Small'); echo $table->generate(); } }
8. use App\HTMLGenerator\TableFactory; use App\HTMLGenerator\TableEvents; use App\HTMLGenerator\Table\Elements\Table; use App\HTMLGenerator\Table\Elements\Row; use App\HTMLGenerator\Table\Elements\Cell; use App\HTMLGenerator\Presenters\HTML5Presenter; use App\Events\EventEmitter; class Reports { function reportGenerator() { $tableFactory = new TableFactory; $table = $tableFactory->newTable(); EventEmitter::emit(TableEvents::TABLE_CREATED, [$table]); $row = new Row; $row->addCell(new Cell('Name')); $table->addRow($row); $htmlPresenter = new HTML5Presenter(); echo $htmlPresenter->render($table); } }
9. Steve! You’re being all loosey-goosey!
10. Rather have an application that doesn’t work at all than failing silently Rather have no users able to register than register without the password field Rather have a contact form burn up in flames than have it send without the message body Rather have the reports email die than have it mail the client 300 notifications in an hour
11. Make your application die often and without remorse
12. Turn all errors into exceptions set_error_handler( function ($level, $message, $file, $line) { throw new ErrorException($message, 0, $level, $file, $line); } );
13. Throw exceptions instead of returning $this->email->to('joe@example.com'); $this->email->from('your@example.com'); $this->email->message('Hi.'); if (! $this->email->send()) { foreach ($this->email->_debug_msg as $error) { // Do something... } } $this->email->clear();
14. $email = new Email; $email->to('joe@example.com'); $email->from('your@example.com'); $email->message('Hi.'); try { $email->send(); } catch (EmailException $e) { // Print error // Log error // etc. }
15. Exceptions are like magical statements
16. function a() { if (! b()) { return false; } do_some_work(); return true; } function b() { if (some_error_condition()) { return false; } } if (! a()) { // error }
17. function a() { b(); do_some_work(); return true; } function b() { if (some_error_condition()) { throw new Exception(); } } try { a(); } catch (Exception $e) { // error }