refactor: route validation errors through AppError and central error handler

Author: PiyushInt

backend/src/middlewares/validateBody.js

@@ -1,14 +1,13 @@
+import { AppError } from '../core/errors.js';
+
 export const validateBody = (schema) => {
     return (req, res, next) => {
         // If there is no body and the schema expects an object, Joi will handle it (or we can pass {} if req.body is undefined, but express.json() gives {} usually).
         // It's safer to pass req.body or {}
         const payload = req.body || {};
         const { error } = schema.validate(payload);
         if (error) {
-            return res.status(400).json({
-                error: 'VALIDATION_ERROR',
-                message: error.details[0].message
-            });
+            return next(new AppError(error.details[0].message, 400, 'VALIDATION_ERROR'));
         }
         next();
     };

frontend/src/pages/CourseDetail.jsx

@@ -40,7 +40,11 @@ const CourseDetail = () => {
 
     const handleCreate = async (e) => {
         e.preventDefault();
-        await dispatch(createAssignment({ courseId: id, assignmentData: newAssignment }));
+        let formattedDate = newAssignment.due_date;
+        if (formattedDate && !formattedDate.includes('T')) {
+            formattedDate = `${formattedDate}T23:59:59.999Z`;
+        }
+        await dispatch(createAssignment({ courseId: id, assignmentData: { ...newAssignment, due_date: formattedDate } }));
         setShowCreateModal(false);
         setNewAssignment({ title: '', description: '', due_date: '' });
     };

frontend/src/services/api.js

@@ -4,6 +4,7 @@ const API_URL = import.meta.env.VITE_API_URL || '/api';
 
 const api = axios.create({
   baseURL: API_URL,
+  timeout: 30000,
   headers: {
     'Content-Type': 'application/json',
   },
@@ -27,12 +28,21 @@ api.interceptors.request.use(
 api.interceptors.response.use(
   (response) => response,
   (error) => {
-    if (error.response && error.response.status === 401) {
-      // Token expired or invalid
-      localStorage.removeItem('token');
-      localStorage.removeItem('user');
-      // Optional: Redirect to login
-      window.location.href = '/login';
+    if (error.response) {
+      if (error.response.status === 401) {
+        // Token expired or invalid
+        localStorage.removeItem('token');
+        localStorage.removeItem('user');
+        // Optional: Redirect to login
+        window.location.href = '/login';
+      }
+      
+      const apiError = error.response.data?.error?.message 
+        || error.response.data?.message 
+        || 'An unexpected error occurred';
+      error.message = apiError;
+    } else {
+      error.message = 'Network error or server unreachable';
     }
     return Promise.reject(error);
   }

frontend/src/store/assignmentSlice.js

@@ -8,7 +8,7 @@ export const fetchAssignments = createAsyncThunk(
         try {
             return await courseService.getCourseAssignments(courseId);
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to fetch assignments');
+            return rejectWithValue(error.message || 'Failed to fetch assignments');
         }
     }
 );
@@ -20,7 +20,7 @@ export const createAssignment = createAsyncThunk(
             const response = await api.post(`/courses/${courseId}/assignments`, assignmentData);
             return response.data;
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to create assignment');
+            return rejectWithValue(error.message || 'Failed to create assignment');
         }
     }
 );
@@ -32,7 +32,7 @@ export const submitAssignment = createAsyncThunk(
             const response = await api.post(`/assignments/${assignmentId}/submit`, { content });
             return response.data;
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to submit assignment');
+            return rejectWithValue(error.message || 'Failed to submit assignment');
         }
     }
 );
@@ -44,7 +44,7 @@ export const fetchSubmissions = createAsyncThunk(
             const response = await api.get(`/assignments/${assignmentId}/submissions`);
             return { assignmentId, submissions: response.data };
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to fetch submissions');
+            return rejectWithValue(error.message || 'Failed to fetch submissions');
         }
     }
 );

frontend/src/store/authSlice.js

@@ -9,7 +9,7 @@ export const loginUser = createAsyncThunk(
             const response = await api.post('/auth/login', credentials);
             return response.data;
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Login failed');
+            return rejectWithValue(error.message || 'Login failed');
         }
     }
 );
@@ -21,7 +21,7 @@ export const registerUser = createAsyncThunk(
             const response = await api.post('/auth/register', userData);
             return response.data;
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Registration failed');
+            return rejectWithValue(error.message || 'Registration failed');
         }
     }
 );

frontend/src/store/courseSlice.js

@@ -7,7 +7,7 @@ export const fetchCourses = createAsyncThunk(
         try {
             return await courseService.getAllCourses();
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to fetch courses');
+            return rejectWithValue(error.message || 'Failed to fetch courses');
         }
     }
 );
@@ -18,7 +18,7 @@ export const fetchEnrolledCourses = createAsyncThunk(
         try {
             return await courseService.getEnrolledCourses();
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to fetch enrolled courses');
+            return rejectWithValue(error.message || 'Failed to fetch enrolled courses');
         }
     }
 );
@@ -29,7 +29,7 @@ export const createNewCourse = createAsyncThunk(
         try {
             return await courseService.createCourse(courseData);
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to create course');
+            return rejectWithValue(error.message || 'Failed to create course');
         }
     }
 );
@@ -40,7 +40,7 @@ export const enrollInCourse = createAsyncThunk(
         try {
             return await courseService.enrollStudent(courseId);
         } catch (error) {
-            return rejectWithValue(error.response?.data?.error || 'Failed to enroll');
+            return rejectWithValue(error.message || 'Failed to enroll');
         }
     }
 );