feat: Add custom exception handling mechanism

example/app_exception_handler.dart

@@ -0,0 +1,81 @@
+import 'package:vania/src/exception/database_exception.dart';
+import 'package:vania/src/exception/exception_handler.dart';
+import 'package:vania/src/exception/not_found_exception.dart';
+import 'package:vania/src/exception/query_exception.dart';
+import 'package:vania/src/exception/validation_exception.dart';
+import 'package:vania/src/http/request/request.dart';
+import 'package:vania/src/http/response/response.dart';
+import 'package:vania/src/service/service_provider.dart';
+import 'package:vania/application.dart';
+
+class DatabaseExceptionHandler extends ExceptionHandler<DatabaseException> {
+  @override
+  Response handle(DatabaseException exception, Request? request) {
+    return Response.json({
+      'success': false,
+      'message': 'Database error occurred',
+      'error': exception.message,
+    }, 500);
+  }
+}
+
+class QueryExceptionHandler extends ExceptionHandler<QueryException> {
+  @override
+  Response handle(QueryException exception, Request? request) {
+    return Response.json({
+      'success': false,
+      'message': 'Query error occurred',
+      'error': exception.cause,
+    }, 500);
+  }
+}
+
+class NotFoundExceptionHandler extends ExceptionHandler<NotFoundException> {
+  @override
+  Response handle(NotFoundException exception, Request? request) {
+    return Response.json({
+      'success': false,
+      'message': exception.message,
+    }, 404);
+  }
+}
+
+class ValidationExceptionHandler extends ExceptionHandler<ValidationException> {
+  @override
+  Response handle(ValidationException exception, Request? request) {
+    return Response.json({
+      'success': false,
+      'message': 'Validation failed',
+      'errors': exception.message,
+    }, 422);
+  }
+}
+
+class ThirdPartyExceptionHandler extends GeneralExceptionHandler {
+  @override
+  Response? handle(dynamic exception, Request? request) {
+    return Response.json({
+      'success': false,
+      'message': 'An unexpected error occurred',
+      'error': exception.toString(),
+    }, 500);
+  }
+}
+
+class AppExceptionServiceProvider extends ServiceProvider {
+  @override
+  Future<void> boot() async {}
+
+  @override
+  Future<void> register() async {
+    Application().addExceptionHandlers({
+      DatabaseException: DatabaseExceptionHandler(),
+      QueryException: QueryExceptionHandler(),
+      NotFoundException: NotFoundExceptionHandler(),
+      ValidationException: ValidationExceptionHandler(),
+    });
+    Application().setGeneralExceptionHandler(
+      ThirdPartyExceptionHandler(),
+    );
+  }
+}

example/main.dart

@@ -1 +1,10 @@
+import 'package:vania/vania.dart';
+import 'app_exception_handler.dart';
 
+void main() async {
+  Application().initialize(
+    config: {
+      'providers': [AppExceptionServiceProvider()],
+    },
+  );
+}

lib/application.dart

@@ -1,4 +1,5 @@
 import 'src/container.dart';
+import 'src/exception/exception_handler.dart';
 import 'src/ioc_container.dart';
 import 'src/localization_handler/localization.dart';
 import 'src/server/base_http_server.dart';
@@ -10,6 +11,9 @@ import 'src/utils/helper.dart' show env;
 class Application extends Container {
   static Application? _singleton;
 
+  final Map<Type, ExceptionHandler> _exceptionHandlers = {};
+  GeneralExceptionHandler? _generalExceptionHandler;
+
   factory Application() {
     if (_singleton == null) {
       _singleton = Application._internal();
@@ -21,6 +25,26 @@ class Application extends Container {
 
   Application._internal();
 
+  void addExceptionHandler<T>(ExceptionHandler<T> handler) {
+    _exceptionHandlers[T] = handler;
+  }
+
+  void addExceptionHandlers(Map<Type, ExceptionHandler> handlers) {
+    _exceptionHandlers.addAll(handlers);
+  }
+
+  void setGeneralExceptionHandler(GeneralExceptionHandler handler) {
+    _generalExceptionHandler = handler;
+  }
+
+  ExceptionHandler? getExceptionHandler(Type type) {
+    return _exceptionHandlers[type];
+  }
+
+  GeneralExceptionHandler? getGeneralExceptionHandler() {
+    return _generalExceptionHandler;
+  }
+
   late BaseHttpServer _server;
 
   Future<void> initialize({

lib/src/authentication/authentication.dart

@@ -183,7 +183,7 @@ class Auth {
       await PersonalAccessToken().query.insert({
         'name': _userGuard,
         'tokenable_id': user['id'],
-        'token': md5.convert(utf8.encode(newToken['access_token'])),
+        'token': md5.convert(utf8.encode(newToken['access_token'])).toString(),
         'created_at': DateTime.now(),
       });
     }
@@ -215,7 +215,7 @@ class Auth {
   ///
   Future<bool> deleteCurrentToken(String token) async {
     await PersonalAccessToken().query
-        .where('token', '=', md5.convert(utf8.encode(token)))
+        .where('token', '=', md5.convert(utf8.encode(token)).toString())
         .update({'deleted_at': DateTime.now()});
     return true;
   }
@@ -254,7 +254,7 @@ class Auth {
       return true;
     } else {
       Map<String, dynamic>? exists = await PersonalAccessToken().query
-          .where('token', '=', md5.convert(utf8.encode(token)))
+          .where('token', '=', md5.convert(utf8.encode(token)).toString())
           .whereNull('deleted_at')
           .first(['id']);
       // Throw 401 Error if token not found
@@ -263,7 +263,7 @@ class Auth {
       }
 
       await PersonalAccessToken().query
-          .where('token', '=', md5.convert(utf8.encode(token)))
+          .where('token', '=', md5.convert(utf8.encode(token)).toString())
           .update({'last_used_at': DateTime.now()});
 
       if (user == null) {

lib/src/exception/exception_handler.dart

@@ -0,0 +1,14 @@
+import 'package:vania/src/http/request/request.dart';
+import 'package:vania/src/http/response/response.dart';
+
+abstract class ExceptionHandler<T> {
+  const ExceptionHandler();
+
+  Response handle(T exception, Request? request);
+}
+
+abstract class GeneralExceptionHandler {
+  const GeneralExceptionHandler();
+
+  Response? handle(dynamic exception, Request? request);
+}

lib/src/http/controller/controller_handler.dart

@@ -1,10 +1,12 @@
 import 'package:vania/src/exception/database_exception.dart';
+import 'package:vania/src/exception/exception_handler.dart';
 import 'package:vania/src/exception/query_exception.dart';
 import 'package:vania/src/exception/validation_exception.dart';
 import 'package:vania/src/http/request/request.dart';
 import 'package:vania/src/http/response/response.dart';
 import 'package:vania/src/route/route_data.dart';
 import 'package:vania/src/route/route_history.dart';
+import 'package:vania/application.dart';
 
 import '../../exception/base_http_exception.dart';
 import '../../exception/invalid_argument_exception.dart';
@@ -51,6 +53,10 @@ class ControllerHandler {
 
       response.makeResponse(request.response);
     } on ValidationException catch (error) {
+      Response? customResponse = _handleException(error, request);
+      if (customResponse != null) {
+        return customResponse.makeResponse(request.response);
+      }
       bool isHtml = request.request.headers
           .value('accept')
           .toString()
@@ -63,17 +69,53 @@ class ControllerHandler {
         error.response(false).makeResponse(request.response);
       }
     } on InvalidArgumentException catch (error) {
+      Response? customResponse = _handleException(error, request);
+      if (customResponse != null) {
+        return customResponse.makeResponse(request.response);
+      }
       _response(request, error.message);
     } on DatabaseException catch (error) {
+      Response? customResponse = _handleException(error, request);
+      if (customResponse != null) {
+        return customResponse.makeResponse(request.response);
+      }
       _response(request, error.message, 500);
     } on QueryException catch (error) {
+      Response? customResponse = _handleException(error, request);
+      if (customResponse != null) {
+        return customResponse.makeResponse(request.response);
+      }
       _response(request, error.cause ?? '', 500);
     } on BaseHttpResponseException catch (error) {
+      Response? customResponse = _handleException(error, request);
+      if (customResponse != null) {
+        return customResponse.makeResponse(request.response);
+      }
       _response(request, error.message, error.code);
     } catch (error) {
+      Response? customResponse = _handleException(error, request);
+      if (customResponse != null) {
+        return customResponse.makeResponse(request.response);
+      }
       _response(request, error.toString());
     }
   }
+
+  Response? _handleException(dynamic exception, Request request) {
+    try {
+      ExceptionHandler? handler =
+          Application().getExceptionHandler(exception.runtimeType);
+      if (handler != null) {
+        return handler.handle(exception, request);
+      }
+      GeneralExceptionHandler? generalHandler =
+          Application().getGeneralExceptionHandler();
+      if (generalHandler != null) {
+        return generalHandler.handle(exception, request);
+      }
+    } catch (_) {}
+    return null;
+  }
 }
 
 void _response(Request req, message, [statusCode = 500]) {

lib/src/http/request/request_handler.dart

@@ -1,5 +1,6 @@
 import 'dart:io';
 import 'package:vania/src/exception/database_exception.dart';
+import 'package:vania/src/exception/exception_handler.dart';
 import 'package:vania/src/exception/query_exception.dart';
 import 'package:vania/src/extensions/extensions.dart';
 import 'package:vania/src/http/response/response.dart';
@@ -24,6 +25,7 @@ import 'package:vania/src/websocket/web_socket_handler.dart';
 import 'package:vania/src/exception/base_http_exception.dart';
 import 'package:vania/src/logger/logger.dart';
 import 'package:vania/src/utils/helper.dart';
+import 'package:vania/application.dart';
 import 'request.dart';
 
 HttpRequest? globalHttpRequest;
@@ -48,6 +50,7 @@ class RequestHandler {
       WebSocketHandler().handler(req);
     } else {
       bool isHtml = req.headers.value('accept').toString().contains('html');
+      Request? request;
       try {
         HttpCors(req);
         RouteData? route = httpRouteHandler(req);
@@ -57,7 +60,7 @@ class RequestHandler {
         String requestMethod = req.method.toUpperCase();
 
         if (route != null) {
-          Request request = Request().from(request: req, route: route);
+          request = Request().from(request: req, route: route);
           await request.extractBody();
 
           if (isHtml) {
@@ -92,6 +95,11 @@ class RequestHandler {
           }
         }
       } on BaseHttpResponseException catch (error) {
+        Response? customResponse = _handleException(error, request);
+        if (customResponse != null) {
+          return customResponse.makeResponse(req.response);
+        }
+
         if (error is NotFoundException && isHtml) {
           if (File('lib/resources/view/errors/404.html').existsSync()) {
             return view('errors/404').makeResponse(req.response);
@@ -120,19 +128,51 @@ class RequestHandler {
 
         error.response(isHtml).makeResponse(req.response);
       } on InvalidArgumentException catch (e) {
+        Response? customResponse = _handleException(e, request);
+        if (customResponse != null) {
+          return customResponse.makeResponse(req.response);
+        }
         Logger.log(e.message, type: Logger.ERROR);
         _response(req, e.message);
       } on DatabaseException catch (error) {
+        Response? customResponse = _handleException(error, request);
+        if (customResponse != null) {
+          return customResponse.makeResponse(req.response);
+        }
         _response(req, error.message);
       } on QueryException catch (error) {
+        Response? customResponse = _handleException(error, request);
+        if (customResponse != null) {
+          return customResponse.makeResponse(req.response);
+        }
         _response(req, error.cause);
       } catch (e) {
+        Response? customResponse = _handleException(e, request);
+        if (customResponse != null) {
+          return customResponse.makeResponse(req.response);
+        }
         Logger.log(e.toString(), type: Logger.ERROR);
         _response(req, e.toString());
       }
     }
   }
 
+  Response? _handleException(dynamic exception, Request? request) {
+    try {
+      ExceptionHandler? handler =
+          Application().getExceptionHandler(exception.runtimeType);
+      if (handler != null) {
+        return handler.handle(exception, request);
+      }
+      GeneralExceptionHandler? generalHandler =
+          Application().getGeneralExceptionHandler();
+      if (generalHandler != null) {
+        return generalHandler.handle(exception, request);
+      }
+    } catch (_) {}
+    return null;
+  }
+
   void _response(HttpRequest req, dynamic message, {int statusCode = 500}) {
     if (req.headers.value('accept').toString().contains('html')) {
       Response.html(message).makeResponse(req.response);

lib/vania.dart

@@ -16,7 +16,18 @@ export 'src/config/config.dart';
 export 'src/cryptographic/hash.dart';
 
 export 'src/exception/base_http_exception.dart';
+export 'src/exception/database_exception.dart';
+export 'src/exception/exception_handler.dart';
+export 'src/exception/forbidden_exception.dart';
+export 'src/exception/http_exception.dart';
+export 'src/exception/internal_server_error.dart';
 export 'src/exception/invalid_argument_exception.dart';
+export 'src/exception/not_found_exception.dart';
+export 'src/exception/page_expired_exception.dart';
+export 'src/exception/query_exception.dart';
+export 'src/exception/redirect_exception.dart';
 export 'src/exception/throttle_exception.dart';
-export 'src/exception/validation_exception.dart';
 export 'src/exception/unauthenticated.dart';
+export 'src/exception/unauthorized_exception.dart';
+export 'src/exception/validation_exception.dart';
+export 'application.dart';