Actualización

main/inc/lib/formvalidator/Rule/UsernameAvailable.php

@@ -0,0 +1,34 @@
+<?php
+/* For licensing terms, see /license.txt */
+
+/**
+ * QuickForm rule to check if a username is available.
+ */
+class HTML_QuickForm_Rule_UsernameAvailable extends HTML_QuickForm_Rule
+{
+    /**
+     * Function to check if a username is available.
+     *
+     * @see HTML_QuickForm_Rule
+     *
+     * @param string $username         Wanted username
+     * @param string $current_username
+     *
+     * @return bool True if username is available
+     */
+    public function validate($username, $current_username = null)
+    {
+        $user_table = Database::get_main_table(TABLE_MAIN_USER);
+        $username = Database::escape_string($username);
+        $current_username = Database::escape_string($current_username);
+
+        $sql = "SELECT * FROM $user_table WHERE username = '$username'";
+        if (!is_null($current_username)) {
+            $sql .= " AND username != '$current_username'";
+        }
+        $res = Database::query($sql);
+        $number = Database::num_rows($res);
+
+        return $number == 0;
+    }
+}