feat: add global exception handler

src/main/java/dev/gfxv/blps/controller/AuthController.java

@@ -23,22 +23,14 @@ public class AuthController {
     }
 
     @PostMapping("/register")
-    public ResponseEntity<?> registerUser(@RequestBody RegisterRequest registerRequest) {
-        try {
-            String response = authService.registerUser(registerRequest);
-            return ResponseEntity.ok(response);
-        } catch (RuntimeException e) {
-            return ResponseEntity.badRequest().body(e.getMessage());
-        }
+    public ResponseEntity<?> registerUser(@RequestBody RegisterRequest request) {
+        String response = authService.registerUser(request);
+        return ResponseEntity.ok(response);
     }
 
     @PostMapping("/login")
-    public ResponseEntity<?> authenticateUser(@RequestBody LoginRequest loginRequest) {
-        try {
-            JwtResponse jwtResponse = authService.authenticateUser(loginRequest);
-            return ResponseEntity.ok(jwtResponse);
-        } catch (RuntimeException e) {
-            return ResponseEntity.badRequest().body(e.getMessage());
-        }
+    public ResponseEntity<?> authenticateUser(@RequestBody LoginRequest request) {
+        JwtResponse jwtResponse = authService.authenticateUser(request);
+        return ResponseEntity.ok(jwtResponse);
     }
 }

src/main/java/dev/gfxv/blps/exception/EmailAlreadyExistsException.java

@@ -0,0 +1,7 @@
+package dev.gfxv.blps.exception;
+
+public class EmailAlreadyExistsException extends RuntimeException {
+    public EmailAlreadyExistsException(String message) {
+        super(message);
+    }
+}

src/main/java/dev/gfxv/blps/exception/GlobalExceptionHandler.java

@@ -0,0 +1,34 @@
+package dev.gfxv.blps.exception;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.authentication.BadCredentialsException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler({UsernameAlreadyExistsException.class, EmailAlreadyExistsException.class})
+    public ResponseEntity<String> handleAlreadyExists(UsernameAlreadyExistsException ex) {
+        System.out.println("triggered handleAlreadyExists");
+        return ResponseEntity.badRequest().body(ex.getMessage());
+    }
+
+    @ExceptionHandler(RuntimeException.class)
+    public ResponseEntity<String> handleRuntimeException(RuntimeException ex) {
+        System.out.println("triggered handleRuntimeException");
+        System.out.println("AHTUNG AHTUNG:" + ex.getMessage());
+        return ResponseEntity
+                .internalServerError()
+                .body("An unexpected error occurred");
+    }
+
+    @ExceptionHandler(BadCredentialsException.class)
+    public ResponseEntity<String> handleBadCredentials(BadCredentialsException ex) {
+        System.out.println("triggered handleBadCredentials");
+        // TODO: probably log?
+        return ResponseEntity
+                .unprocessableEntity()
+                .body("Invalid username or password");
+    }
+}

src/main/java/dev/gfxv/blps/exception/UsernameAlreadyExistsException.java

@@ -0,0 +1,7 @@
+package dev.gfxv.blps.exception;
+
+public class UsernameAlreadyExistsException extends RuntimeException {
+    public UsernameAlreadyExistsException(String message) {
+        super(message);
+    }
+}

src/main/java/dev/gfxv/blps/service/AuthService.java

@@ -2,6 +2,8 @@ package dev.gfxv.blps.service;
 
 import dev.gfxv.blps.entity.Role;
 import dev.gfxv.blps.entity.User;
+import dev.gfxv.blps.exception.EmailAlreadyExistsException;
+import dev.gfxv.blps.exception.UsernameAlreadyExistsException;
 import dev.gfxv.blps.payload.request.LoginRequest;
 import dev.gfxv.blps.payload.request.RegisterRequest;
 import dev.gfxv.blps.payload.response.JwtResponse;
@@ -48,11 +50,11 @@ public class AuthService {
 
     public String registerUser(RegisterRequest registerRequest) {
         if (userRepository.existsByUsername(registerRequest.getUsername())) {
-            throw new RuntimeException("Error: Username is already taken!");
+            throw new UsernameAlreadyExistsException("Username is already taken!");
         }
 
         if (userRepository.existsByEmail(registerRequest.getEmail())) {
-            throw new RuntimeException("Error: Email is already in use!");
+            throw new EmailAlreadyExistsException("Email is already in use!");
         }
 
         User user = new User();