Question

I use gcache to cache whole website pages to HTML and next i only read it and show to the user. It looks like this:

$enableCache = true; 
if ($enableCache)
{
    include("gcache.php");
    $cache = new gCache;
    $cache->folder = "temp/";
    $id = join("", $_GET);
    $id = ereg_replace("[^A-Za-z0-9]", "", $id);
    $cache->contentId=$id;
    $cache->timeout = 5; 
    /* its mean gCache cached the whole page */
    /* so, gcache, decide if he must response the compressed or */
    /* uncompressed cache*/
    $cache->isPage = true; 
    if ($cache->Valid()) {
        echo $cache->content;
        die;
    }
    $cache->capture();
}

And works fine. Now i’ve added a link “login” in the header of the site. When person clicks it it redirects person to subpage where he/she provides creditencials, session parameter is set (before is session_start called):

  $_SESSION['theUser'] = $userId;
  header( "refresh:1;url=http://mysite.com"); 

And person is redirected to the mysite.com. But the problem is he / she sees the site got from cache. So in upper right corner there is “log in” again, but i set that when $_SESSION[‘theUser’] is set it should show it and provide a link to log out. But it does not display because it returns to user the unlogged in version of website.

How to fix this?

Answer 1

I assume, that the reason of using cache in this way is to minimize server load and response times. But this can be achieved by more simple way not using third-parity plugins/classes/stuff:

<?php
    global $cachefile;
    //encode cache file name with sha1 
    $cachefilename = sha1($_SERVER['REQUEST_URI']);
    //remove trailing slash
    $cachefile = rtrim(sys_get_temp_dir (),'\\/').DIRECTORY_SEPARATOR.$cachefilename.'.cache';
     // How long to keep cache file?
    $cachetime = 60*5;    //5min
    // Is cache file still fresh? If so, serve it.   
    if (file_exists($cachefile) && filesize($cachefile)>100 && time() - $cachetime < filemtime($cachefile)  )  {
      readfile($cachefile);
      exit;
    }

    function cacheOutputtoFile()   {
     global $cachefile;
     $webpage = ob_get_contents();
     if ($fp = fopen($cachefile, 'w+'))
        {
            // Do an exclusive lock
            if (flock($fp, LOCK_EX))
            { 
               // Truncate file 
               ftruncate($fp, 0); 
               fwrite($fp, $webpage);
               fclose($fp);
            }
        }
    }

    ob_start();
    register_shutdown_function("cacheOutputtoFile");

Note: You must use register_shutdown_function() instead of using cacheOutputtoFile()
as parameter of ob_start() as socket is already closed when callback function is called, then the client not get the echo $webpage output.

Usage: Put this file in your root server folder (or wherever you want) and require it one on top of every page you want to cache.

require_once("cacheable.php");