Centralized Cache URI

Adjusting the storages paths of the CI cache can be labor-intensive, so I decided to make it a little less expensive. Make this mod to MY_Output and you should be able to plug in Suffix Cache, Slightly Better Caching, or make any other adjustments to the CI caching conventions -- all from one spot.

I've included snippets for the two Cache libraries mentioned above.

<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');

/**
 * One Cache URI to Rule Them All
 *
 * Cache URI building is coded in duplicate as of 1.6.2 trunk, so I
 * refactored it to make it a little more manageable.  If you're using
 * Slightly Better Caching or Suffix Cache, the codebases can be merged 
 * to give you more reign over cache filing practices.
 *
 * @package        CodeIgniter
 * @subpackage    Libraries
 * @hacked-by    Bradford Mar
 * @copyright    Copyright (c) 2008, Bradford Mar
 * @license    http://codeigniter.com/wiki/Copyrights_and_Content_License/
 */
class MY_Output extends CI_Output {

    
    /**
     * _get_from_session
     *
     * Attempts to get a value from a global object. If path is an array, attempts
     * to digg deeper into that object. Returns FALSE on error.
     *
     * @access    public
     * @param    string || array
     * @return    string || FALSE
     */
    function _get_from_session ( $path )
    {
        if ( is_string($path) )
        {
            $path = array($path);
        }
        
        do {
            
            $el = array_shift($path);
            
            if ( !isset($current) && isset($_SESSION[$el]) )
            {
                $current = $_SESSION[$el];
            }
            else if ( isset($current) && isset($current[$el]) )
            {
                $current = $current[$el];
            }
            else
            {
                unset($current);
                break;
            }
            
        } while (count($path) > 0);
        
        if ( isset($current) )
        {
            return $current;
        }
        else
        {
            return FALSE;
        }
    }

    
    /**
     * Get the uri of a given cached page
     *
     * @access    public
     * @return    void
     */    

    function get_cache_URI($set_uri = null, $append_suffix = true){
        $CFG =& load_class('Config');
        $URI =& load_class('URI');
        
        $set_uri = (isset($set_uri)) ? $set_uri : $URI->uri_string;
    
        $cache_path = ($CFG->item('cache_path') == '') ? BASEPATH.'cache/' : $CFG->item('cache_path');
                
        if ( ! is_dir($cache_path) OR ! is_writable($cache_path))
        {
             return FALSE;
         }
        
        /*
         * Build the file path.  The file name is an MD5 hash of the full URI
         * If we make the suffix optional in _write_cache() be sure to do
         * so here too. <josh@surber.us>
         */
        $uri =    $CFG->item('base_url').
                $CFG->item('index_page').
                $set_uri . '.';
        if ($append_suffix)
        {
            $uri.=$URI->suffix;
        } else
        {
            // Get type type
            if ( FALSE !== ($type = $this->_get_from_session($CFG->item('cache_type_source'))) )
            {
                $uri.= 'sess:'.$type;
            }
        }
        return array('path'=>$cache_path, 'uri'=>$uri);
    }


    // --------------------------------------------------------------------
    
    /**
     * Manually clear a cached file
     *
     * @access    public
     * @return    void
     */    

    function clear_page_cache($set_uri = null, $append_suffix = true){
        $cacheuri = $this->get_cache_URI($set_uri, $append_suffix);
        $filepath = $cacheuri['path'];
        $filepath .= md5($cacheuri['uri']);        
        if(file_exists($filepath))
        {
            touch($filepath);
            unlink&#40;$filepath&#41;;
            log_message('debug', "Cache file has expired. File deleted for: ".$cacheuri['uri']);
        } else
        {
            return FALSE;
        }
    }

}
// END MY_Output Class

/* End of file MY_Output.php */
/* Location: ./system/application/libraries/MY_Output.php */

Make edits to _display_cache() and _write_cache like so:

    // --------------------------------------------------------------------
    
    /**
     * Update/serve a cached file
     *
     * @access    public
     * @return    void
     */    

    function _display_cache(&$CFG, &$RTR)
    {

// moved to function get_cache_URI()        
/*        $URI =& load_class('URI');
    
        $cache_path = ($CFG->item('cache_path') == '') ? BASEPATH.'cache/' : $CFG->item('cache_path');
            
        if ( ! is_dir($cache_path) OR ! is_really_writable($cache_path))
        {
            return FALSE;
        }
        
        // Build the file path.  The file name is an MD5 hash of the full URI
        $uri =    $CFG->item('base_url').
                $CFG->item('index_page').
                $URI->uri_string;
*/
        $cacheuri = $this->get_cache_URI();
        $uri = $cacheuri['uri'];
        $cache_path = $cacheuri['path'];
        
        $filepath = $cache_path.md5($uri);

        if ( ! @file_exists($filepath))
        {
            return FALSE;
        }
// etc...

    /**
     * Write a Cache File
     *
     * @access    public
     * @return    void
     */    
    function _write_cache($output)
    {
        $CI =& get_instance();

// moved to function get_cache_URI()        
/*        $path = $CI->config->item('cache_path');
    
        $cache_path = ($path == '') ? BASEPATH.'cache/' : $path;
        
        if ( ! is_dir($cache_path) OR ! is_really_writable($cache_path))
        {
            return;
        }
        
        $uri =    $CI->config->item('base_url').
                $CI->config->item('index_page').
                $CI->uri->uri_string();
*/        
        $cacheuri = $this->get_cache_URI();
        $uri = $cacheuri['uri'];
        $cache_path = $cacheuri['path'];

        $cache_path .= md5($uri);

        if ( ! $fp = @fopen($cache_path, 'wb'))
        {
            log_message('error', "Unable to write cache file: ".$cache_path);
            return;
        }
//  etc...