prefmanager.php

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<?php
require_once("DB.php");

/**
 * A simple preference manager, takes userid, preference name pairs and returns the value
 * of that preference.
 *  
 * CREATE TABLE `preferences` (
 * `user_id` varchar( 255 ) NOT NULL default '',
 * `pref_id` varchar( 32 ) NOT NULL default '',
 * `pref_value` longtext NOT NULL ,
 * 	PRIMARY KEY ( `user_id` , `pref_id` )
 * )
 * 
 * @author Jon Wood <[e-mail]>
 * @package Auth_PrefManager
 * @category Authentication
 */
class Auth_PrefManager
{
    /**
     * The database object.
     * @var object
     * @access private
     */
    var $_db;

    /**
     * The user name to get preferences from if the user specified doesn't
     * have that preference set.
     * @var string
     * @access private
     */
    var $_defaultUser = "__default__";

    /**
     * Should we search for default values, or just fail when we find out that
     * the specified user didn't have it set.
     * 
     * @var bool
     * @access private
     */
    var $_returnDefaults = true;

    /**
     * The table containing the preferences.
     * @var string
     * @access private
     */
    var $_table = "preferences";

    /**
     * The column containing user ids.
     * @var string
     * @access private
     */
    var $_userColumn = "user_id";

    /**
     * The column containing preference names.
     * @var string
     * @access private
     */
    var $_nameColumn = "pref_id";

    /**
     * The column containing preference values.
     * @var string
     * @access private
     */
    var $_valueColumn = "pref_value";

	/**
	 * The quoted value column.
	 * @var string
	 * @access private
	 */
	var $_valueColumnQuoted = "pref_value";
	
    /**
     * The session variable that the cache array is stored in.
     * @var string
     * @access private
     */
     var $_cacheName = "prefCache";

    /**
     * The last error given.
     * @var string
     * @access private
     */
    var $_lastError;

    /**
     * Defines whether the cache should be used or not.
     * @var bool
     * @access private
     */
    var $_useCache = true;
	
    /**
     * Defines whether values should be serialized before saving.
     * @var bool
     * @access private
     */
    var $_serialize = false;
    
    /**
     * Constructor
     * 
     * Options:
     *  table: The table to get prefs from. [preferences]
     *  userColumn: The field name to search for userid's [user_id]
     *  nameColumn: The field name to search for preference names [pref_name]
     *  valueColumn: The field name to search for preference values [pref_value]
     *  defaultUser: The userid assigned to default values [__default__]
     *  cacheName: The name of cache in the session variable ($_SESSION[cacheName]) [prefsCache]
     *  useCache: Whether or not values should be cached.
     *  serialize: Should preference values be serialzed before saving?
     *
     * @param string $dsn The DSN of the database connection to make, or a DB object.
     * @param array $properties An array of properties to set.
     * @param string $defaultUser The default user to manage for.
     * @return bool Success or failure.
     * @access public
     */
    function Auth_PrefManager($dsn, $properties = NULL)
    {
        // Connect to the database.
        if (isset($dsn)) {
            if (is_string($dsn)) {
				$this->_db = DB::Connect($dsn);
                if (DB::isError($this->_db)) {
                    $this->_lastError = "DB Error: ".$this->_db->getMessage();
                }
			} else if (is_subclass_of($dsn, 'db_common')) {
                $this->_db = &$dsn;
            } else {
				$this->_lastError = "Invalid DSN specified.";
				return false;
            }
        } else {
            $this->_lastError = "No DSN specified.";
            return false;
        }

        if (is_array($properties)) {
            if (isset($properties["table"]))        { $this->_table = $this->_db->quoteIdentifier($properties["table"]); }
            if (isset($properties["userColumn"]))   { $this->_userColumn = $this->_db->quoteIdentifier($properties["userColumn"]); }
            if (isset($properties["nameColumn"]))   { $this->_nameColumn = $this->_db->quoteIdentifier($properties["nameColumn"]); }
            if (isset($properties["valueColumn"]))  { $this->_valueColumn = $properties["valueColumn"]; }
			if (isset($properties["valueColumn"]))  { $this->_valueColumnQuoted = $this->_db->quoteIdentifier($properties["valueColumn"]); }
            if (isset($properties["defaultUser"]))  { $this->_defaultUser = $properties["defaultUser"]; }
            if (isset($properties["cacheName"]))    { $this->_cacheName = $properties["cacheName"]; }
	        if (isset($properties["useCache"]))     { $this->_useCache = $properties["useCache"]; }
            if (isset($properties["serialize"]))    { $this->_serialize = $properties["serialize"]; }
        }

        return true;
    }

    function setReturnDefaults($returnDefaults = true)
    {
        if (is_bool($returnDefaults)) {
            $this->_returnDefaults = $returnDefaults;
        }
    }

    /**
     * Sets whether the cache should be used.
     * 
     * @param bool $use Should the cache be used.
     * @access public
     */
    function useCache($use = true)
    {
        $this->_useCache = $use;
    }
	
    /**
     * Cleans out the cache.
     * 
     * @access public
     */
    function clearCache()
    {
        unset($_SESSION[$this->_cacheName]);
    }

    /**
     * Get a preference for the specified user, or, if returning default values
     * is enabled, the default.
     * 
     * @param string $user_id The user to get the preference for.
     * @param string $pref_id The preference to get.
     * @param bool $showDefaults Should default values be searched (overrides the global setting).
     * @return mixed The value if it's found, or NULL if it isn't.
     * @access public
     */
    function getPref($user_id, $pref_id, $showDefaults = true)
    {
        if (isset($_SESSION[$this->_cacheName][$user_id][$pref_id]) && $this->_useCache) {
            // Value is cached for the specified user, so give them the cached copy.
            return $_SESSION[$this->_cacheName][$user_id][$pref_id];
        } else {
            // Not cached, search the database for this user's preference.
            $query = sprintf("SELECT * FROM %s WHERE %s=%s AND %s=%s", $this->_table,
	                                                               $this->_userColumn,
                                                                       $this->_db->quote($user_id),
                                                                       $this->_nameColumn,
                                                                       $this->_db->quote($pref_id));
            $result = $this->_db->query($query);
            if (DB::isError($result)) {
                // Ouch! The query failed!