Added new callback to the account controller to validate usernames

application/controllers/Account.php

@@ -102,4 +102,27 @@ class Account extends EA_Controller {
             json_exception($e);
         }
     }
+
+    /**
+     * Make sure the username is valid and unique in the database. 
+     */
+    public function validate_username()
+    {
+        try
+        {
+            $username = request('username');
+
+            $user_id = request('user_id');
+
+            $is_valid = $this->users_model->validate_username($username, $user_id);
+
+            json_response([
+                'is_valid' => $is_valid,
+            ]);
+        }
+        catch (Throwable $e)
+        {
+            json_exception($e);
+        }
+    }
 }

assets/js/http/account_http_client.js

@@ -28,7 +28,26 @@ App.Http.Account = (function () {
         return $.post(url, data);
     }
 
+    /**
+     * Validate username.
+     *
+     * @param {String} username
+     *
+     * @return {Object}
+     */
+    function validateUsername(username) {
+        const url = App.Utils.Url.siteUrl('account/validate_username');
+
+        const data = {
+            csrf_token: App.Vars.csrf_token,
+            username
+        };
+
+        return $.post(url, data);
+    }
+
     return {
-        save
+        save,
+        validateUsername
     };
 })();