checking user exists or not

Author: ShubhamSupekar

src/main/java/com/example/treaders/controller/AllController.java

@@ -55,14 +55,19 @@ public String Login(){
 
 
     @PostMapping("/authenticate")
-    public String authenticate(@RequestParam String email, @RequestParam String password){
+    public String authenticate(@RequestParam String email, @RequestParam String password,Model model){
         UserFormat user = UserRepo.findByEmail(email);
+        if(user == null){
+            model.addAttribute("errorMessage", "User doesn't exist");
+            return "login";
+        }
         if(user!=null && passwordEncoder.matches(password,user.getPassword())){
             UserLoggedIn = true;
             UserName = user.getUsername();
             return "redirect:/home";
         }else{
-            return "redirect:/signup";
+            model.addAttribute("errorMessage", "Wrong password");
+            return "login";
         }
     }
 
@@ -90,6 +95,10 @@ public String Signup(){
     @PostMapping("/newuser")
     public String addNewUser(@RequestParam String email,@RequestParam String username, @RequestParam String password,Model model){
         UserFormat user=new UserFormat();
+        if(UserRepo.findByEmail(email)!=null){
+            model.addAttribute("errorMessage","This email already exists");
+            return "signup";
+        }
         user.setEmail(email);
         user.setUsername(username);
         String regex = "^(?=.*[A-Z])(?=.*[a-z])(?=.*\\d)(?=.*[@#]).+$";

src/main/resources/static/css/login.css

@@ -60,3 +60,15 @@ body {
     text-align: center;
     margin-top: 10px;
 }
+
+/* New CSS for Error Message */
+.login-container .error {
+    color: #d9534f; /* Bootstrap error color */
+    background-color: #f2dede; /* Light red background for error messages */
+    border: 1px solid #ebccd1; /* Border color matching the background */
+    padding: 10px; /* Add some padding */
+    margin-bottom: 20px; /* Space below the error message */
+    border-radius: 5px; /* Slightly rounded corners */
+    font-size: 0.9em; /* Slightly smaller font size */
+    text-align: center; /* Center the error text */
+}

src/main/resources/templates/login.html

@@ -13,6 +13,8 @@ <h2>Login</h2>
         <div class="message"></div>
         <input type="text" name="email" placeholder="Email Id" required>
         <input type="password" name="password" placeholder="Password" required>
+        <!-- Display the error message if there is one -->
+        <div th:if="${errorMessage != null}" th:text="${errorMessage}" class="error"></div>
         <input type="submit" value="Login">
     </form>
     <p class="signup-text">New user? Sign up <a href="/signup">here</a>.</p>