fix: fix some stuff

frontend/src/app/login-success/login-success.component.ts

@@ -1,4 +1,4 @@
-import { Component, inject, OnInit } from '@angular/core';
+import { ChangeDetectionStrategy, Component, inject, OnInit } from '@angular/core';
 import { UserService } from '../service/user.service';
 import { KeycloakService } from 'keycloak-angular';
 import { Router } from '@angular/router';
@@ -8,7 +8,8 @@ import { Router } from '@angular/router';
   standalone: true,
   imports: [],
   templateUrl: './login-success.component.html',
-  styleUrl: './login-success.component.css'
+  styleUrl: './login-success.component.css',
+  changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class LoginSuccessComponent implements OnInit{
   private userService: UserService = inject(UserService);
@@ -17,7 +18,7 @@ export class LoginSuccessComponent implements OnInit{
 
   async ngOnInit() {
     const userProfile = await this.keycloakService.loadUserProfile();
-    const user = this.userService.getCurrentUser(userProfile);
+    const user = await this.userService.getOrCreateUser(userProfile);
     sessionStorage.setItem('user', JSON.stringify(user));
 
     // this.router.navigate(['']);

frontend/src/app/model/User.ts

@@ -0,0 +1,4 @@
+export interface User {
+  keycloakId: string;
+  username: string;
+}

frontend/src/app/service/user.service.ts

@@ -1,7 +1,8 @@
 import { inject, Injectable } from '@angular/core';
 import { HttpClient } from '@angular/common/http';
 import { KeycloakProfile } from 'keycloak-js';
-import { async } from 'rxjs';
+import { async, Observable } from 'rxjs';
+import { User } from '../model/User';
 
 @Injectable({
   providedIn: 'root',
@@ -9,18 +10,18 @@ import { async } from 'rxjs';
 export class UserService {
   private http: HttpClient = inject(HttpClient);
 
-  public getUser(id: string) {
-    return this.http.get<{ keycloakId: string, username: string } | null>(`/backend/user/${id}`);
+  public getUser(id: string): Observable<User|null> {
+    return this.http.get<User|null>(`/backend/user/${id}`);
   }
 
-  public createUser(id: string, username: string) {
-    return this.http.post<{ keycloakId: string, username: string }>('/backend/user', {
+  public createUser(id: string, username: string): Observable<User> {
+    return this.http.post<User>('/backend/user', {
       keycloakId: id,
       username: username,
     });
   }
 
-  public async getCurrentUser(userProfile: KeycloakProfile) {
+  public async getOrCreateUser(userProfile: KeycloakProfile) {
     if (userProfile.id == null) {
       return;
     }