578   //

   578   // Generate an ETag

   579   // Optimize HTML by replacing newlines with spaces (excludes <pre>, <script>, and <style> blocks)

   579   /*

   580   //

   580   // format: first 10 digits of SHA1 of page name, user id in hex, user and auth levels, page timestamp in hex

   581   if ($aggressive_optimize_html)

   581   $etag = substr(sha1($paths->namespace . ':' . $paths->page_id), 0, 10) . '-' .

   582           "u{$session->user_id}l{$session->user_level}a{$session->auth_level}-" .

   583           dechex($page_timestamp);

   584           

   585   if ( isset($_SERVER['HTTP_IF_NONE_MATCH']) )

   583     // Load up the HTML

   587     if ( "\"$etag\"" == $_SERVER['HTTP_IF_NONE_MATCH'] )

   584     $html = ob_get_contents();

   588     {

   585     @ob_end_clean();

   589       header('HTTP/1.1 304 Not Modified');

   586     

   590       exit();

   587     $html = aggressive_optimize_html($html);

   591     }

   588     

   592   }

   589     // Re-enable output buffering to allow the Gzip function (below) to work

   590     ob_start();

   591     

   592     // Generate an ETag

   593     // format: first 10 digits of SHA1 of page name, user id in hex, user and auth levels, page timestamp in hex

   594     $etag = substr(sha1($paths->namespace . ':' . $paths->page_id), 0, 10) . '-' .

   595             "u{$session->user_id}l{$session->user_level}a{$session->auth_level}-" .

   596             dechex($page_timestamp);

   598     if ( isset($_SERVER['HTTP_IF_NONE_MATCH']) )

   594   header("ETag: \"$etag\"");

   599     {

   595   */

   600       if ( "\"$etag\"" == $_SERVER['HTTP_IF_NONE_MATCH'] )

   601       {

   602         header('HTTP/1.1 304 Not Modified');

   603         exit();

   604       }

   605     }

   606             

   607     // header("ETag: \"$etag\"");

   608     

   609     // Done, send it to the user

   610     echo( $html );

   611   }