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                <?php  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                /**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * ownCloud - Calendar App  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * @author Georg Ehrke  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * @copyright 2016 Georg Ehrke <[email protected]>  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * @author Raghu Nayyar  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * @copyright 2016 Raghu Nayyar <[email protected]>  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * This library is free software; you can redistribute it and/or  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * License as published by the Free Software Foundation; either  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * version 3 of the License, or any later version.  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * This library is distributed in the hope that it will be useful,  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * but WITHOUT ANY WARRANTY; without even the implied warranty of  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * GNU AFFERO GENERAL PUBLIC LICENSE for more details.  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * You should have received a copy of the GNU Affero General Public  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                namespace OCA\Calendar\Controller;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OC\AppFramework\Http;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\AppFramework\Controller;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\AppFramework\Http\DataDisplayResponse;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\AppFramework\Http\JSONResponse;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\AppFramework\Http\NotFoundResponse;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\AppFramework\Http\TemplateResponse;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\IConfig;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\IRequest;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                use OCP\IUserSession;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                class ViewController extends Controller { | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @var IConfig  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	private $config;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @var IUserSession  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	private $userSession;  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param string $appName  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param IRequest $request an instance of the request  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param IConfig $config  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param IUserSession $userSession  | 
            
            
                                                                                                            
                                                                
            
                                    
            
            
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                	 */  | 
            
            
                                                                        
                            
            
                                    
            
            
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                	public function __construct($appName, IRequest $request,  | 
            
            
                                                                        
                            
            
                                    
            
            
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                								IUserSession $userSession, IConfig $config) { | 
            
            
                                                                        
                            
            
                                    
            
            
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                		parent::__construct($appName, $request);  | 
            
            
                                                                        
                            
            
                                    
            
            
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                		$this->config = $config;  | 
            
            
                                                                        
                            
            
                                    
            
            
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                		$this->userSession = $userSession;  | 
            
            
                                                                        
                            
            
                                    
            
            
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                	}  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @NoAdminRequired  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @NoCSRFRequired  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @return TemplateResponse  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	public function index() { | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		$isAssetPipelineEnabled = $this->config->getSystemValue('asset-pipeline.enabled', false); | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		if ($isAssetPipelineEnabled) { | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                			return new TemplateResponse('calendar', 'main-asset-pipeline-unsupported'); | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		}  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		$user = $this->userSession->getUser();  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		$userId = $user->getUID();  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		$emailAddress = $user->getEMailAddress();  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		$appVersion = $this->config->getAppValue($this->appName, 'installed_version');  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		$defaultView = $this->config->getUserValue($userId, $this->appName, 'currentView', 'month');  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		return new TemplateResponse('calendar', 'main', [ | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                			'appVersion' => $appVersion,  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                			'defaultView' => $defaultView,  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                			'emailAddress' => $emailAddress,  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		]);  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	}  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @NoAdminRequired  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param string $id  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @return DataDisplayResponse  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	public function getTimezone($id) { | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		if (!in_array($id, $this->getTimezoneList())) { | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                			return new NotFoundResponse();  | 
            
                            
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                		}  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		$tzData = file_get_contents(__DIR__ . '/../timezones/' . $id);  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		return new DataDisplayResponse($tzData, HTTP::STATUS_OK, [  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                			'content-type' => 'text/calendar',  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		]);  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	}  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @NoAdminRequired  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param $region  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param $city  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @return DataDisplayResponse  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	public function getTimezoneWithRegion($region, $city) { | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		return $this->getTimezone($region . '-' . $city);  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	}  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @NoAdminRequired  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param $region  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param $subregion  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @param $city  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * @return DataDisplayResponse  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	public function getTimezoneWithSubRegion($region, $subregion, $city) { | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                		return $this->getTimezone($region . '-' . $subregion . '-' . $city);  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	}  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	/**  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 * get a list of default timezones  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                	 *  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                 | 
                	 * @return array  | 
            
            
                                                                                                            
                            
            
                                    
            
            
                | 
                    135
                 | 
                                    
                                                     | 
                
                 | 
                	 */  | 
            
            
                                                                                                            
                            
            
                                    
            
            
                | 
                    136
                 | 
                                    
                                                     | 
                
                 | 
                	private function getTimezoneList() { | 
            
            
                                                                                                            
                            
            
                                    
            
            
                | 
                    137
                 | 
                                    
                                                     | 
                
                 | 
                		$allFiles = scandir(__DIR__ . '/../timezones/');  | 
            
            
                                                                                                            
                            
            
                                    
            
            
                | 
                    138
                 | 
                                    
                                                     | 
                
                 | 
                 | 
            
            
                                                                                                            
                            
            
                                    
            
            
                | 
                    139
                 | 
                                    
                                                     | 
                
                 | 
                		return array_values(array_filter($allFiles, function($file) { | 
            
            
                                                                                                            
                            
            
                                    
            
            
                | 
                    140
                 | 
                                    
                                                     | 
                
                 | 
                			return (substr($file, -4) === '.ics');  | 
            
            
                                                                                                            
                            
            
                                    
            
            
                | 
                    141
                 | 
                                    
                                                     | 
                
                 | 
                		}));  | 
            
            
                                                                                                            
                                                                
            
                                    
            
            
                | 
                    142
                 | 
                                    
                                                     | 
                
                 | 
                	}  | 
            
            
                                                        
            
                                    
            
            
                | 
                    143
                 | 
                                    
                                                     | 
                
                 | 
                }  | 
            
            
                        
If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.
Let’s take a look at an example:
Our function
my_functionexpects aPostobject, and outputs the author of the post. The base classPostreturns a simple string and outputting a simple string will work just fine. However, the child classBlogPostwhich is a sub-type ofPostinstead decided to return anobject, and is therefore violating the SOLID principles. If aBlogPostwere passed tomy_function, PHP would not complain, but ultimately fail when executing thestrtouppercall in its body.