Index: moodle/lib/moodlelib.php
--- moodle/lib/moodlelib.php Base (1.1264)
+++ moodle/lib/moodlelib.php Locally Modified (Based On 1.1264)
@@ -219,6 +219,10 @@
  */
 define('PARAM_URL',      'url');
 
+/**
+ * PARAM_USERNAME - Clean username to only contains specified characters.
+ */
+define('PARAM_USERNAME',    'username');
 
 
 ///// DEPRECATED PARAM TYPES OR ALIASES - DO NOT USE FOR NEW CODE  /////
@@ -463,6 +467,7 @@
  * @uses PARAM_BASE64
  * @uses PARAM_TAG
  * @uses PARAM_SEQUENCE
+ * @uses PARAM_USERNAME
  * @param mixed $param the variable we are cleaning
  * @param int $type expected format of param after cleaning.
  * @return mixed
@@ -720,6 +725,14 @@
                 return '';  // Specified theme is not installed
             }
 
+        case PARAM_USERNAME:
+            $param = str_replace(" " , "", $param);
+            if (empty($CFG->extendedusernamechars)) {                                                              
+                //regular expression, eliminate all chars except: alphanum, dash (-), and period (.) characters.
+                $param = preg_replace('/[^\-\.[:alnum:]]/i', '', $param);
+            } 
+            return $param;
+
         default:                 // throw error, switched parameters in optional_param or another serious problem
             print_error("unknownparamtype", '', '', $type);
     }