[svn r12590] Added functions to deal with the "anonymous user" (a user who's DB status is 6), that will help deal with tools that record progress and are open to the public.

main/inc/lib/main_api.lib.php

@@ -370,6 +370,10 @@ function api_get_path($path_type)
 */
 function api_get_user_id()
 {
+	if(empty($GLOBALS['_user']['user_id']))
+	{
+		return 0;
+	}
 	return $GLOBALS['_user']['user_id'];
 }
 /**
@@ -445,6 +449,32 @@ function api_get_course_setting($setting_name)
 	}
 	return -1;
 }
+/**
+ * Gets an anonymous user ID
+ * 
+ * For some tools that need tracking, like the learnpath tool, it is necessary
+ * to have a usable user-id to enable some kind of tracking, even if not
+ * perfect. An anonymous ID is taken from the users table by looking for a
+ * status of "6" (anonymous).
+ * @return	int	User ID of the anonymous user, or O if no anonymous user found
+ */
+function api_get_anonymous_id()
+{
+	$table = Database::get_main_table(TABLE_MAIN_USER);
+	$sql = "SELECT user_id FROM $table WHERE status = 6";
+	$res = api_sql_query($sql,__FILE__,__LINE__);
+	if(Database::num_rows($res)>0)
+	{
+		$row = Database::fetch_array($res);
+		//error_log('api_get_anonymous_id() returns '.$row['user_id'],0);
+		return $row['user_id'];
+	}
+	else //no anonymous user was found
+	{
+		return 0;
+	}
+}
+
 /**
  * Returns the cidreq parameter name + current course id
 */
@@ -754,6 +784,29 @@ function api_check_password($password)
 	}
 	return ($cptLettres >= 3 && $cptChiffres >= 2) ? true : false;
 }
+/**
+ * Clear the user ID from the session if it was the anonymous user. Generally
+ * used on out-of-tools pages to remove a user ID that could otherwise be used
+ * in the wrong context.
+ * This function is to be used in conjunction with the api_set_anonymous()
+ * function to simulate the user existence in case of an anonymous visit.
+ * @return	bool	true if succesfully unregistered, false if not anonymous. 
+ */
+function api_clear_anonymous()
+{
+	global $_user;
+	if(api_is_anonymous($_user['user_id']))
+	{
+		unset($_user['user_id']);
+		api_session_unregister('_uid');
+		return true;
+	}
+	else
+	{
+		return false;
+	}
+}
+
 /**
  * truncates a string
  *
@@ -835,6 +888,38 @@ function api_set_failure($failureType)
 	$api_failureList[] = $failureType;
 	return false;
 }
+
+/**
+ * Sets the current user as anonymous if it hasn't been identified yet. This 
+ * function should be used inside a tool only. The function api_clear_anonymous()
+ * acts in the opposite direction by clearing the anonymous user's data every
+ * time we get on a course homepage or on a neutral page (index, admin, my space)
+ * @return	bool	true if set user as anonymous, false if user was already logged in or anonymous id could not be found
+ */
+function api_set_anonymous()
+{
+	global $_user;
+	if(!empty($_user['user_id']))
+	{
+		return false;
+	}
+	else
+	{
+		$user_id = api_get_anonymous_id();
+		if($user_id == 0)
+		{
+			return false;
+		}
+		else
+		{
+			api_session_unregister('_user');
+			$_user['user_id'] = $user_id;
+			api_session_register('_user');
+			return true;
+		}
+	}
+}
+
 /**
  * get the last failure stored in $api_failureList;
  *
@@ -1333,6 +1418,27 @@ function api_is_allowed($tool, $action, $task_id = 0)
 		return false;
 }
 
+/**
+ * Tells whether this user is an anonymous user
+ * @param	int		User ID (optional, will take session ID if not provided)
+ * @return	bool	true if this user is anonymous, false otherwise
+ */
+function api_is_anonymous($user_id=null)
+{
+	if(!isset($user_id))
+	{
+		$user_id = api_get_user_id();
+	}
+	$info = api_get_user_info($user_id);
+	if($info['status'] == 6)
+	{
+		error_log('Returning true from api_is_anonymous()',0);
+		return true;
+	}
+	error_log('Returning false from api_is_anonymous()',0);
+	return false;
+}
+
 /**
  * Displays message "You are not allowed here..." and exits the entire script.
  * @param	bool	Whether or not to print headers (default = false -> does not print them)