| 1 |  |  | <?php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 2 |  |  | /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 3 |  |  |  * Copyright (c) 2015-2015 Andreas Heigl<[email protected]> | 
            
                                                                                                            
                            
            
                                    
            
            
                | 4 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 5 |  |  |  * Permission is hereby granted, free of charge, to any person obtaining a copy | 
            
                                                                                                            
                            
            
                                    
            
            
                | 6 |  |  |  * of this software and associated documentation files (the "Software"), to deal | 
            
                                                                                                            
                            
            
                                    
            
            
                | 7 |  |  |  * in the Software without restriction, including without limitation the rights | 
            
                                                                                                            
                            
            
                                    
            
            
                | 8 |  |  |  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | 
            
                                                                                                            
                            
            
                                    
            
            
                | 9 |  |  |  * copies of the Software, and to permit persons to whom the Software is | 
            
                                                                                                            
                            
            
                                    
            
            
                | 10 |  |  |  * furnished to do so, subject to the following conditions: | 
            
                                                                                                            
                            
            
                                    
            
            
                | 11 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 12 |  |  |  * The above copyright notice and this permission notice shall be included in | 
            
                                                                                                            
                            
            
                                    
            
            
                | 13 |  |  |  * all copies or substantial portions of the Software. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 14 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 15 |  |  |  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | 
            
                                                                                                            
                            
            
                                    
            
            
                | 16 |  |  |  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | 
            
                                                                                                            
                            
            
                                    
            
            
                | 17 |  |  |  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | 
            
                                                                                                            
                            
            
                                    
            
            
                | 18 |  |  |  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | 
            
                                                                                                            
                            
            
                                    
            
            
                | 19 |  |  |  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | 
            
                                                                                                            
                            
            
                                    
            
            
                | 20 |  |  |  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | 
            
                                                                                                            
                            
            
                                    
            
            
                | 21 |  |  |  * THE SOFTWARE. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 22 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 23 |  |  |  * @author    Andreas Heigl<[email protected]> | 
            
                                                                                                            
                            
            
                                    
            
            
                | 24 |  |  |  * @copyright 2015-2015 Andreas Heigl/callingallpapers.com | 
            
                                                                                                            
                            
            
                                    
            
            
                | 25 |  |  |  * @license   http://www.opensource.org/licenses/mit-license.php MIT-License | 
            
                                                                                                            
                            
            
                                    
            
            
                | 26 |  |  |  * @version   0.0 | 
            
                                                                                                            
                            
            
                                    
            
            
                | 27 |  |  |  * @since     06.03.2012 | 
            
                                                                                                            
                            
            
                                    
            
            
                | 28 |  |  |  * @link      http://github.com/joindin/callingallpapers | 
            
                                                                                                            
                            
            
                                    
            
            
                | 29 |  |  |  */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 30 |  |  | namespace Callingallpapers\Parser\Lanyrd; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 31 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 32 |  |  | use Callingallpapers\Entity\Cfp; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 33 |  |  | use Callingallpapers\Parser\Lanyrd\LanyrdEntryParser; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 34 |  |  | use Callingallpapers\Parser\ParserInterface; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 35 |  |  | use Callingallpapers\Service\TimezoneService; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 36 |  |  | use Callingallpapers\Writer\WriterInterface; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 37 |  |  | use GuzzleHttp\Client; | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 38 |  |  |  | 
            
                                                                        
                            
            
                                    
            
            
                | 39 |  |  | class LanyrdCfpParser implements ParserInterface | 
            
                                                                        
                            
            
                                    
            
            
                | 40 |  |  | { | 
            
                                                                        
                            
            
                                    
            
            
                | 41 |  |  |     protected $tzService; | 
            
                                                                        
                            
            
                                    
            
            
                | 42 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 43 |  |  |     public function __construct(TimezoneService $tzService) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 44 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 45 |  |  |         $this->tzService = $tzService; | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 46 |  |  |     } | 
            
                                                                        
                            
            
                                    
            
            
                | 47 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 48 |  |  |     public function parse(WriterInterface $writer) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 49 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 50 |  |  |         $uri = 'http://lanyrd.com/calls/'; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 51 |  |  |         $i = 0; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 52 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 53 |  |  |         $pages = 0; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 54 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 55 |  |  |         do { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 56 |  |  |             $dom = new \DOMDocument('1.0', 'UTF-8'); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 57 |  |  |             $dom->loadHTMLFile($uri . '?page=' . ($i+1)); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 58 |  |  |             $dom->preserveWhiteSpace = false; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 59 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 60 |  |  |             $xpath = new \DOMXPath($dom); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 61 |  |  |             $nodes = $xpath->query("//div[@class='pagination']/ol/li[last()]/a"); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 62 |  |  |             if ($nodes->length < 1) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 63 |  |  |                 continue; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 64 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 65 |  |  |             $pages = $nodes[0]->textContent; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 66 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 67 |  |  |             $xpath = new \DOMXPath($dom); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 68 |  |  |             $nodes = $xpath->query("//*[contains(@class, 'call-list-open')]"); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 69 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 70 |  |  |             $cfp = new Cfp(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 71 |  |  |             $client = new Client([ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 72 |  |  |                 'headers'=> [ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 73 |  |  |                     'User-Agent' => 'callingallpapers.com - Location to lat/lon-translation - For infos write to [email protected]', | 
            
                                                                                                            
                            
            
                                    
            
            
                | 74 |  |  |                 ], | 
            
                                                                                                            
                            
            
                                    
            
            
                | 75 |  |  |             ]); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 76 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 77 |  |  |             $lanyrdEntryParser = new Entry($cfp, $client, $this->tzService); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 78 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 79 |  |  |             foreach ($nodes as $node) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 80 |  |  |                 try { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 81 |  |  |                     /** @var \DOMNode $node */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 82 |  |  |                     $links = $xpath->query('.//a[text()="Call for speakers"]', | 
            
                                                                                                            
                            
            
                                    
            
            
                | 83 |  |  |                         $node); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 84 |  |  |                     if ($links->length < 1) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 85 |  |  |                         continue; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 86 |  |  |                     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 87 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 88 |  |  |                     $eventPageUrl = $links->item(0)->attributes->getNamedItem('href')->textContent; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 89 |  |  |                     error_log($eventPageUrl); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 90 |  |  |                     if (! $eventPageUrl) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 91 |  |  |                         continue; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 92 |  |  |                     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 93 |  |  |                     $writer->write($lanyrdEntryParser->parse($eventPageUrl)); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 94 |  |  |                 } catch (\Exception $e) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 95 |  |  |                     error_log($e->getMEssage()); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 96 |  |  |                 } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 97 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 98 |  |  |         } while (++$i < $pages); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 99 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 100 |  |  |         return true; | 
                            
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                | 101 |  |  |     } | 
            
                                                        
            
                                    
            
            
                | 102 |  |  | } | 
            
                                                        
            
                                    
            
            
                | 103 |  |  |  | 
            
                        
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.