php使用gzip压缩传输js和css文件的方法

<?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);          }      }  }