php解析字符串里所有URL地址的方法

本文实例讲述了php解析字符串里所有URL地址的方法。分享给大家供大家参考。具体如下：

    <?php
    // $html = the html on the page
    // $current_url = the full url that the html came from
    //(only needed for $repath)
    // $repath = converts ../ and / and // urls to full valid urls
    function pageLinks($html, $current_url = "", $repath = false){
      preg_match_all("/\<a.+?href=(\"|')(?!javascript:|#)(.+?)(\"|')/i", $html, $matches);
      $links = array();
      if(isset($matches[2])){
        $links = $matches[2];
      }
      if($repath && count($links) > 0 && strlen($current_url) > 0){
        $pathi   = pathinfo($current_url);
        $dir    = $pathi["dirname"];
        $base    = parse_url($current_url);
        $split_path = explode("/", $dir);
        $url    = "";
        foreach($links as $k => $link){
          if(preg_match("/^\.\./", $link)){
            $total = substr_count($link, "../");
            for($i = 0; $i < $total; $i++){
              array_pop($split_path);
            }
            $url = implode("/", $split_path) . "/" . str_replace("../", "", $link);
          }elseif(preg_match("/^\/\//", $link)){
            $url = $base["scheme"] . ":" . $link;
          }elseif(preg_match("/^\/|^.\//", $link)){
            $url = $base["scheme"] . "://" . $base["host"] . $link;
          }elseif(preg_match("/^[a-zA-Z0-9]/", $link)){
            if(preg_match("/^http/", $link)){
              $url = $link;
            }else{
              $url    = $dir . "/" . $link;
            }
          }
          $links[$k] = $url;
        }
      }
      return $links;
    }
    header("content-type: text/plain");
    $url = "http://www.jb51.net";
    $html = file_get_contents($url);
    // Gets links from the page:
    print_r(pageLinks($html));
    // Gets links from the page and formats them to a full valid url:
    print_r(pageLinks($html, $url, true));

希望本文所述对大家的php程序设计有所帮助。