PHP, 爬虫 PHP实现最简单爬虫原型

最简单的爬虫模型应该是这样的：给一个初始url，爬虫把内容扒下拉，找页面里的url，在以这些url为起点，开始爬。

下面是一个最简单的php实现的爬虫模型。

<?php/** * 爬虫程序 -- 原型 *  * BookMoth 2009-02-21 *//** * 从给定的url获取html内容 * * @param string $url * @return string */function _getU<b>%本文@来源gao@!dai!ma.com搞$$代^@码!网</b><strong>搞代gaodaima码</strong>rlContent($url){$handle = fopen($url, "r");if($handle){$content = stream_get_contents($handle,1024*1024);return $content;}else{return false;}}/** * 从html内容中筛选链接 * * @param string $web_content * @return array */function _filterUrl($web_content){$reg_tag_a = '/<[a|A].*?href=[/'/"]{0,1}([^>/'/"/ ]*).*?>/';$result = preg_match_all($reg_tag_a,$web_content,$match_result);if($result){return $match_result[1];}}/** * 修正相对路径 * * @param string $base_url * @param array $url_list * @return array */function _reviseUrl($base_url,$url_list){$url_info = parse_url($base_url);$base_url = $url_info["scheme"].'://';if($url_info["user"]&&$url_info["pass"]){$base_url .= $url_info["user"].":".$url_info["pass"]."@";}$base_url .= $url_info["host"];if($url_info["port"]){$base_url .= ":".$url_info["port"];}$base_url .= $url_info["path"];print_r($base_url);if(is_array($url_list)){foreach ($url_list as $url_item) {if(preg_match('/^http/',$url_item)){//已经是完整的url$result[] = $url_item;}else {//不完整的url$real_url = $base_url.'/'.$url_item;$result[] = $real_url;}}return $result;}else {return;}}/** * 爬虫 * * @param string $url * @return array */function crawler($url){$content = _getUrlContent($url);if($content){$url_list = _reviseUrl($url,_filterUrl($content));if($url_list){return $url_list;}else {return ;}}else{return ;}}/** * 测试用主程序 * */function main(){$current_url = "http://hao123.com/";//初始url$fp_puts = fopen("url.txt","ab");//记录url列表$fp_gets = fopen("url.txt","r");//保存url列表do{$result_url_arr = crawler($current_url);if($result_url_arr){foreach ($result_url_arr as $url) {fputs($fp_puts,$url."/r/n");}}}while ($current_url = fgets($fp_gets,1024));//不断获得url}main();?>

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