php实现递归抓取网页类实例

<?php class crawler{ private $_depth=5; private $_urls=array(); function extract_links($url) { if(!$this->_started){ $this->_started=1; $curr_depth=0; }else{ $curr_depth++; } if($curr_depth<$this->_depth) { $data=file_get_contents($url); if(preg_match_all('/((?:http|https)://(?:)*(?:[a-zA-Z0-9_-]{1,15}.+[a-zA-Z0-9_]{1,}){1,}(?:[a-zA-Z0-9_/.-?&:%,!;]*))/',$data,$urls12)) { foreach($urls12[0] as $k=>$v){ $check=get_headers($v,1); if(strstr($v,$url) && $check[0]=='HTTP/1.1 200 OK' && !array_search($v,$this->_urls) && $curr_depth<$this->_depth){ $this->_urls[]=$v; $this->extract_links($v); } } } } return $this->_urls; } } ?>