php使用gzip压缩传输js和css文件的方法

本文实例讲述了php使用gzip压缩传输js和css文件的方法。分享给大家供大家参考。具体如下：

    <?php
      /**
       * 完整调用示例:
       * 1、combine.php?t=j&b;=public&fs;=jslib.jquery,function
       * 
       * 该例子调用的是网站根目录下的public/jslib/jquery.js和public/function.js
       * 
       * 2、combine.php?t=j&fs;=jslib.jquery,function
       * 
       * 该例子调用的是网站根目录下的jslib/jquery.js和function.js
       * 
       * 3、combine.php?t=c&b;=public.css&fs;=common,index
       * 
       * 该例子调用的是网站根目录下的public/css/common.css和public/css/index.css
       * 
       * 4、combine.php?t=c&fs;=css.common
       * 该例子调用的是网站根目录下的css/common.css
       * 
       * 注:多个文件名之间用,分隔;只有一个文件名最后不要有,
       *   用,分隔的多个文件会被压缩进一个文件，一次性传给浏览器
       **/
      $is_bad_request=false;
      $cache = true;
      $doc_root_uri=$_SERVER['DOCUMENT_ROOT'].'/';
      $cachedir = $doc_root_uri . 'public/cache';
      //文件类型，j为js，c为css
      $type=isset($_GET['t'])?($_GET['t']=='j'||$_GET['t']=='c'?$_GET['t']:''):'';
      //存放js和css文件的基目录, 例如:?b=public.js 代表的是/public/js文件夹，出发点是网站根目录
      //基目录参数不是必须的，如果有基目录那么这个基目录就会附加在文件名之前
      $base =isset($_GET['b'])?($doc_root_uri.str_replace('.','/',$_GET['b'])):$doc_root_uri;
      //文件名列表，文件名不带后缀名.比如基目录是
      //文件名的格式是 :基目录(如果有)+文件包名+文件名
      //例如:类型是j,
      //   文件名public.js.jquery
      //   如果有基路径且为public，
      //   那么转换后的文件名就是/public/public/js/jquery.js
      //   如果没有基路径
      //   那么转换后的文件名就是/public/js/jquery.js
      //多个文件名之间用,分隔
      $fs=isset($_GET['fs'])?str_replace('.','/',$_GET['fs']):'';
      $fs=str_replace(',','.'.($type=='j'?'js,':'css,'),$fs);
      $fs=$fs.($type=='j'?'.js':'.css');
      if($type==''||$fs==''){$is_bad_request=true;}
      //die($base);
      if($is_bad_request){header ("HTTP/1.0 503 Not Implemented");}
      $file_type=$type=='j'?'javascript':'css';
      $elements = explode(',',preg_replace('/([^?]*).*/', '\1', $fs));
      // Determine last modification date of the files
      $lastmodified = 0;
      while (list(,$element) = each($elements)) {
        $path =$base . '/' . $element;
        if (($type == 'j' && substr($path, -3) != '.js') || 
          ($type == 'c' && substr($path, -4) != '.css')) {
          header ("HTTP/1.0 403 Forbidden");
          exit;  
        }
        if (substr($path, 0, strlen($base)) != $base || !file_exists($path)) {
          header ("HTTP/1.0 404 Not Found");
          exit;
        }
        $lastmodified = max($lastmodified, filemtime($path));
      }
      // Send Etag hash
      $hash = $lastmodified . '-' . md5($fs);
      header ("Etag: \"" . $hash . "\"");
      if (isset($_SERVER['HTTP_IF_NONE_MATCH']) && 
        stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) == '"' . $hash . '"') 
      {
        // Return visit and no modifications, so do not send anything
        header ("HTTP/1.0 304 Not Modified");
        header ("Content-Type: text/" . $file_type);
        header ('Content-Length: 0');
      } 
      else
      {
        // First time visit or files were modified
        if ($cache) 
        {
          // Determine supported compression method
          $gzip = strstr($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip');
          $deflate = strstr($_SERVER['HTTP_ACCEPT_ENCODING'], 'deflate');
          // Determine used compression method
          $encoding = $gzip ? 'gzip' : ($deflate ? 'deflate' : 'none');
          // Check for buggy versions of Internet Explorer
          if (!strstr($_SERVER['HTTP_USER_AGENT'], 'Opera') && 
            preg_match('/^Mozilla\/4\.0 \(compatible; MSIE ([0-9]\.[0-9])/i', $_SERVER['HTTP_USER_AGENT'], $matches)) {
            $version = floatval($matches[1]);
            if ($version < 6)
              $encoding = 'none';
            if ($version == 6 && !strstr($_SERVER['HTTP_USER_AGENT'], 'EV1')) 
              $encoding = 'none';
          }
          // Try the cache first to see if the combined files were already generated
          $cachefile = 'cache-' . $hash . '.' . $file_type . ($encoding != 'none' ? '.' . $encoding : '');
          if (file_exists($cachedir . '/' . $cachefile)) {
            if ($fp = fopen($cachedir . '/' . $cachefile, 'rb')) {
              if ($encoding != 'none') {
                header ("Content-Encoding: " . $encoding);
              }
              header ("Content-Type: text/" . $file_type);
              header ("Content-Length: " . filesize($cachedir . '/' . $cachefile));
              fpassthru($fp);
              fclose($fp);
              exit;
            }
          }
        }
        // Get contents of the files
        $contents = '';
        reset($elements);
        while (list(,$element) = each($elements)) {
          $path = $base . '/' . $element;
          $contents .= "\n\n" . file_get_contents($path);
        }
        // Send Content-Type
        header ("Content-Type: text/" . $file_type);
        if (isset($encoding) && $encoding != 'none') 
        {
          // Send compressed contents
          $contents = gzencode($contents, 9, $gzip ? FORCE_GZIP : FORCE_DEFLATE);
          header ("Content-Encoding: " . $encoding);
          header ('Content-Length: ' . strlen($contents));
          echo $contents;
        } 
        else
        {
          // Send regular contents
          header ('Content-Length: ' . strlen($contents));
          echo $contents;
        }
        // Store cache
        if ($cache) {
          if ($fp = fopen($cachedir . '/' . $cachefile, 'wb')) {
            fwrite($fp, $contents);
            fclose($fp);
          }
        }
      }

希望本文所述对大家的php程序设计有所帮助。