extends the functionality of oauth in Stirling PDF

src/main/java/stirling/software/SPDF/controller/api/UserController.java

@@ -47,8 +47,11 @@ public class UserController {
             model.addAttribute("error", "Username already exists");
             return "register";
         }
-
-        userService.saveUser(requestModel.getUsername(), requestModel.getPassword());
+        try {
+            userService.saveUser(requestModel.getUsername(), requestModel.getPassword());
+        } catch (IllegalArgumentException e) {
+            return "redirect:/login?messageType=invalidUsername";
+        }
         return "redirect:/login?registered=true";
     }
 
@@ -92,7 +95,11 @@ public class UserController {
         }
 
         if (newUsername != null && newUsername.length() > 0) {
-            userService.changeUsername(user, newUsername);
+            try {
+                userService.changeUsername(user, newUsername);
+            } catch (IllegalArgumentException e) {
+                return new RedirectView("/account?messageType=invalidUsername");
+            }
         }
 
         // Logout using Spring's utility

src/main/java/stirling/software/SPDF/controller/web/AccountWebController.java

@@ -109,8 +109,9 @@ public class AccountWebController {
                 OAuth2User userDetails = (OAuth2User) principal;
 
                 // Retrieve username and other attributes
-                username = userDetails.getAttribute("email");
-
+                username =
+                        userDetails.getAttribute(
+                                applicationProperties.getSecurity().getOAUTH2().getUseAsUsername());
                 // Add oAuth2 Login attributes to the model
                 model.addAttribute("oAuth2Login", true);
             }