Update README

README.md

@@ -1,5 +1,50 @@
 # EduCat - AI-Powered Note Revision Platform
 
+EduCat is a modern web application that helps students improve their study notes using AI. Built with Node.js, Express, and EJS, it features secure file upload capabilities, AI-powered note revision, interactive quizzes, and an intelligent chatbot.
+
+## Features
+
+### 🔐 **Security & Authentication**
+- Secure login and registration system
+- Session-based authentication with flash messages
+- Password hashing with bcrypt
+- Strict file type whitelisting for secure uploads
+
+### 📁 **Document Processing**
+- Upload notes in multiple formats (PDF, DOC, DOCX, XLSX, XLS, TXT, MD, JSON, CSV, XML)
+- Secure document extraction with proper error handling
+- File preview with extraction information and metadata
+- Separate storage for original uploads and AI-revised notes
+
+### 🤖 **AI-Powered Features**
+- **Note Revision**: Automatically improve, summarize, and generate study questions
+- **Interactive Chatbot**: Chat with AI for study assistance
+- **Quiz Generation**: Create interactive quizzes from uploaded documents
+- **Smart Content Extraction**: Extract text from various document formats
+
+### 📊 **Dashboard & Management**
+- Modern dashboard to manage uploaded files
+- Separate sections for original files and AI-revised notes
+- File preview with extraction status and metadata
+- Download and delete functionality for all file types
+
+### 🎯 **Quiz System**
+- Generate quizzes from uploaded documents
+- Multiple question types (multiple choice, true/false, short answer)
+- Comprehensive quiz review with explanations
+- Statistics tracking for quiz performance
+
+### 🎨 **Modern UI/UX**
+- Beautiful, responsive design with Bootstrap 5
+- Custom SVG favicon and branded interface
+- Improved file icons and visual indicators
+- Mobile-friendly responsive layout
+
+### 🔗 **AI Integration**
+- Connected to Flowise at https://flowise.suika.cc/
+- RAG (Retrieval-Augmented Generation) capabilities
+- Secure API integration with proper error handling-Powered Note Revision Platform
+
 EduCat is a modern web application that helps students improve their study notes using AI. Built with Node.js, Express, and EJS, it features file upload capabilities, AI-powered note revision, and an interactive chatbot.
 
 ## Features
@@ -17,10 +62,15 @@ EduCat is a modern web application that helps students improve their study notes
 - **Backend**: Node.js, Express.js
 - **Frontend**: EJS templates, Bootstrap 5, Font Awesome
 - **Authentication**: bcrypt for password hashing, express-session
-- **File Handling**: Multer for file uploads
+- **File Handling**: Multer for secure file uploads with type validation
-- **AI Integration**: Flowise API integration
+- **Document Processing**: 
+  - PDFParse for PDF extraction
+  - Mammoth for Word document processing
+  - ExcelJS for secure Excel file handling (replaced vulnerable xlsx)
+- **AI Integration**: Flowise API integration with RAG capabilities
 - **Session Management**: Express Session with flash messages
-- **Styling**: Custom CSS with Bootstrap
+- **Security**: File type whitelisting, secure extraction methods
+- **Styling**: Custom CSS with Bootstrap and custom SVG favicon
 
 ## Installation
 
@@ -35,6 +85,17 @@ EduCat is a modern web application that helps students improve their study notes
    npm install
    ```
 
+   **Key Dependencies:**
+   - `express` - Web framework
+   - `ejs` - Template engine
+   - `multer` - File upload handling
+   - `bcrypt` - Password hashing
+   - `express-session` - Session management
+   - `pdf-parse` - PDF text extraction
+   - `mammoth` - Word document processing
+   - `exceljs` - Secure Excel file handling
+   - `axios` - HTTP client for API calls
+
 3. **Configure environment variables**:
    - Copy `.env.example` to `.env` (if exists) or create a new `.env` file
    - Update the following variables:
@@ -75,8 +136,12 @@ EduCat is a modern web application that helps students improve their study notes
 ### Uploading Notes
 1. After logging in, click "Upload Notes" in the navigation
 2. Drag and drop your file or click to browse
-3. Select a file (PDF, DOC, TXT, or image)
+3. Select a supported file type:
+   - **Documents**: PDF, DOC, DOCX
+   - **Spreadsheets**: XLSX, XLS  
+   - **Text Files**: TXT, MD, JSON, CSV, XML
 4. Click "Upload & Process"
+5. View file preview with extraction information
 
 ### Revising Notes
 1. Go to your Dashboard to see uploaded files
@@ -86,11 +151,19 @@ EduCat is a modern web application that helps students improve their study notes
    - **Summarize**: Creates concise summaries
    - **Generate Questions**: Creates study questions
 4. Click "Revise with AI" to process
+5. Save and download revised notes from the "AI-Revised Notes" section
+
+### Quiz System
+1. Upload a document to generate quizzes from
+2. Navigate to the quiz section
+3. Take interactive quizzes with multiple question types
+4. Review answers with detailed explanations
+5. Track your quiz performance and statistics
 
 ### Using the Chatbot
 1. Navigate to the "Chat" section
 2. Type your questions about study materials or academic topics
-3. Get instant AI-powered responses
+3. Get instant AI-powered responses using RAG technology
 
 ## Project Structure
 
@@ -101,8 +174,10 @@ EduCat/
 │   │   └── style.css
 │   ├── js/
 │   │   └── main.js
-│   └── images/
+│   ├── images/
-│       └── logo.png
+│   │   └── favicon.svg
+│   ├── favicon.svg
+│   └── favicon-32x32.svg
 ├── views/
 │   ├── partials/
 │   │   ├── header.ejs
@@ -112,8 +187,14 @@ EduCat/
 │   ├── revise.ejs
 │   ├── chat.ejs
 │   ├── dashboard.ejs
+│   ├── quiz.ejs
 │   └── error.ejs
 ├── uploads/
+│   └── revised-notes/
+├── data/
+│   ├── user-files/
+│   ├── revised-files/
+│   └── quiz-results/
 ├── server.js
 ├── package.json
 └── .env
@@ -121,14 +202,38 @@ EduCat/
 
 ## API Endpoints
 
+### Authentication & Core Routes
 - `GET /` - Home page
+- `GET /login` - Login page
+- `POST /login` - Handle login
+- `GET /register` - Registration page
+- `POST /register` - Handle registration
+- `GET /logout` - Logout user
+
+### File Management
 - `GET /upload` - File upload page
-- `POST /upload` - Handle file uploads
+- `POST /upload` - Handle file uploads with validation
+- `GET /dashboard` - User dashboard with file management
+- `GET /api/files/:fileId/preview` - File preview with extraction info
+- `DELETE /api/files/:fileId` - Delete uploaded file
+
+### AI-Powered Features
 - `GET /revise/:fileId` - Note revision page
 - `POST /api/revise` - AI revision endpoint
+- `POST /api/save-revised` - Save revised notes
+- `GET /api/download-revised/:fileId` - Download revised notes
+- `GET /api/revised-files/:fileId/info` - Get revised file info
+- `DELETE /api/revised-files/:fileId` - Delete revised file
+
+### Quiz System
+- `GET /quiz` - Quiz interface
+- `POST /api/quiz/generate` - Generate quiz from document
+- `POST /api/quiz/submit` - Submit quiz answers
+- `GET /api/quiz/results` - Get quiz statistics
+
+### Chat Integration
 - `GET /chat` - Chat interface
-- `POST /api/chat` - Chat API endpoint
+- `POST /api/chat` - Chat API endpoint with RAG support
-- `GET /dashboard` - User dashboard
 
 ## Configuration
 
@@ -144,24 +249,37 @@ EduCat/
 ### File Upload Settings
 
 - **Maximum file size**: 10MB
-- **Allowed formats**: PDF, DOC, DOCX, TXT, JPG, JPEG, PNG, GIF
+- **Allowed formats**: PDF, DOC, DOCX, XLSX, XLS, TXT, MD, JSON, CSV, XML
-- **Upload directory**: `uploads/`
+- **Upload directory**: `uploads/` (original files)
+- **Revised notes directory**: `uploads/revised-notes/`
+- **Security**: Strict file type whitelisting with MIME type validation
+- **Processing**: Automatic text extraction with error handling
 
 ## Customization
 
 ### Styling
 - Edit `public/css/style.css` to customize the appearance
 - The design uses Bootstrap 5 with custom CSS variables
+- Custom SVG favicon and file icons for better visual consistency
+- Responsive design optimized for mobile and desktop
 
 ### AI Integration
 - Modify the Flowise API calls in `server.js`
 - Update prompts in the `/api/revise` endpoint
 - Customize chat responses in the `/api/chat` endpoint
+- Configure RAG settings for document-based queries
+
+### Security
+- File type restrictions configured in server.js and main.js
+- MIME type validation for uploaded files
+- Secure document extraction methods
+- Session security with proper secret management
 
 ### Adding Features
 - Add new routes in `server.js`
 - Create corresponding EJS templates in `views/`
 - Add client-side JavaScript in `public/js/main.js`
+- Update CSS in `public/css/style.css`
 
 ## Troubleshooting
 
@@ -169,17 +287,38 @@ EduCat/
 
 1. **File upload fails**:
    - Check file size (max 10MB)
-   - Verify file format is supported
+   - Verify file format is supported (PDF, DOC, DOCX, XLSX, XLS, TXT, MD, JSON, CSV, XML)
-   - Ensure `uploads/` directory exists
+   - Ensure `uploads/` and `uploads/revised-notes/` directories exist
+   - Check file type validation in both client and server
 
-2. **AI responses don't work**:
+2. **Document extraction errors**:
+   - Verify document is not corrupted
+   - Check extraction status in file preview
+   - Ensure proper permissions for file access
+   - Review server logs for specific extraction errors
+
+3. **AI responses don't work**:
    - Verify Flowise API URL is correct
    - Check if your chatflow ID is valid
    - Ensure Flowise server is accessible
+   - Verify RAG configuration for document-based queries
 
-3. **Session issues**:
+4. **Quiz generation fails**:
-   - Verify SESSION_SECRET is set
+   - Ensure document has sufficient text content
+   - Check if document extraction was successful
+   - Verify AI service is properly connected
+   - Review quiz generation prompts
+
+5. **Session issues**:
+   - Verify SESSION_SECRET is set in .env
    - Check if sessions are properly configured
+   - Clear browser cookies and try again
+
+6. **Revised notes not saving**:
+   - Ensure `uploads/revised-notes/` directory exists
+   - Check file permissions
+   - Verify sufficient disk space
+   - Review server logs for save errors
 
 ### Development
 
@@ -189,6 +328,58 @@ npm install -g nodemon
 npm run dev
 ```
 
+## Recent Updates & Security Improvements
+
+### Version 2.0 Security Enhancements
+- **🔒 Enhanced Security**: Replaced vulnerable `xlsx` library with secure `exceljs` for Excel processing
+- **🛡️ File Type Whitelisting**: Implemented strict file type validation to prevent malicious uploads
+- **🔍 MIME Type Validation**: Added comprehensive file type checking on both client and server
+- **🗂️ Secure Document Processing**: Improved extraction methods with proper error handling
+
+### UI/UX Improvements
+- **🎨 Custom Favicon**: Added custom SVG favicon for brand consistency
+- **📱 Responsive Design**: Enhanced mobile-friendly interface with improved layouts
+- **🔧 File Icons**: Updated file type icons for better visual clarity
+- **📊 Dashboard Enhancements**: Separate sections for original and revised files
+- **🏷️ Badge System**: Improved status indicators and badge alignment
+
+### New Features
+- **💾 Revised Notes Management**: Save, download, and manage AI-revised notes separately
+- **🎯 Enhanced Quiz System**: Fixed short-answer questions with explanations
+- **📈 Quiz Statistics**: Comprehensive tracking of quiz performance
+- **🔍 File Preview**: Detailed extraction information and metadata display
+- **📁 Persistent Storage**: Improved file tracking and session management
+
+### Performance & Reliability
+- **⚡ Optimized Extraction**: Faster and more reliable document processing
+- **🔄 Error Handling**: Comprehensive error handling for all file operations
+- **💪 Robust API**: Improved API endpoints with better validation
+- **🧹 Code Refactoring**: Cleaner, more maintainable codebase
+
+## Deployment & Production
+
+### Production Considerations
+- Set strong `SESSION_SECRET` in production environment
+- Configure proper file upload limits based on server capacity
+- Set up proper logging and monitoring
+- Implement rate limiting for API endpoints
+- Configure HTTPS for secure file uploads
+- Set up backup procedures for uploaded files and data
+
+### Environment Setup
+- Ensure Node.js 14+ is installed
+- Create proper directory structure with correct permissions
+- Configure environment variables for production
+- Set up reverse proxy (nginx/Apache) if needed
+- Configure SSL certificates for HTTPS
+
+### Monitoring & Maintenance
+- Monitor disk space for uploads directory
+- Set up log rotation for application logs
+- Regular security updates for dependencies
+- Monitor API usage and performance
+- Backup user data and quiz results regularly
+
 ## Contributing
 
 1. Fork the repository

server.js

@@ -238,15 +238,43 @@ const upload = multer({
     fileSize: 10 * 1024 * 1024 // 10MB limit
   },
   fileFilter: (req, file, cb) => {
-    // Allow text files, PDFs, and images
+    // Define allowed file types for RAG processing - only text-extractable documents
-    const allowedTypes = /jpeg|jpg|png|gif|pdf|txt|doc|docx/;
+    const allowedExtensions = ['.pdf', '.txt', '.doc', '.docx', '.xlsx', '.xls', '.md', '.json', '.csv', '.xml'];
-    const extname = allowedTypes.test(path.extname(file.originalname).toLowerCase());
+    const allowedMimeTypes = [
-    const mimetype = allowedTypes.test(file.mimetype);
+      'application/pdf',
+      'text/plain',
+      'text/markdown',
+      'text/csv',
+      'text/xml',
+      'application/xml',
+      'application/json',
+      'application/msword',
+      'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+      'application/vnd.ms-excel',
+      'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
+    ];
     
-    if (mimetype && extname) {
+    const fileExtension = path.extname(file.originalname).toLowerCase();
+    const fileMimeType = file.mimetype.toLowerCase();
+    
+    // Check if file extension is allowed
+    const isExtensionAllowed = allowedExtensions.includes(fileExtension);
+    
+    // Check if MIME type is allowed
+    const isMimeTypeAllowed = allowedMimeTypes.includes(fileMimeType);
+    
+    // Additional validation for specific file types
+    if (isExtensionAllowed && isMimeTypeAllowed) {
       return cb(null, true);
     } else {
-      cb(new Error('Only text files, PDFs, and images are allowed!'));
+      // Provide specific error messages for different rejection reasons
+      if (!isExtensionAllowed) {
+        return cb(new Error(`File type "${fileExtension}" is not supported. Only document files (PDF, Word, Excel, text files) are allowed for RAG processing.`));
+      } else if (!isMimeTypeAllowed) {
+        return cb(new Error(`MIME type "${fileMimeType}" is not supported. Please upload valid document files only.`));
+      } else {
+        return cb(new Error('Invalid file type. Only text-extractable documents are allowed to prevent RAG corruption.'));
+      }
     }
   }
 });

views/partials/header.ejs

@@ -4,6 +4,13 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title><%= title %></title>
+    
+    <!-- Favicon -->
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg">
+    <link rel="icon" type="image/svg+xml" sizes="32x32" href="/favicon-32x32.svg">
+    <link rel="apple-touch-icon" sizes="180x180" href="/images/favicon.svg">
+    <meta name="theme-color" content="#007bff">
+    
     <link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap/5.3.0/css/bootstrap.min.css" rel="stylesheet">
     <link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css" rel="stylesheet">
     <link href="/css/style.css" rel="stylesheet">

views/upload.ejs

@@ -14,12 +14,18 @@
                         <i class="fas fa-cloud-upload-alt fa-3x text-primary mb-3"></i>
                         <h5>Drag & Drop your files here</h5>
                         <p class="text-muted">or click to browse</p>
-                        <input type="file" id="noteFile" name="noteFile" class="d-none" accept=".pdf,.doc,.docx,.txt,.jpg,.jpeg,.png,.gif">
+                        <input type="file" id="noteFile" name="noteFile" class="d-none" accept=".pdf,.doc,.docx,.txt,.xlsx,.xls,.md,.json,.csv,.xml">
                         <button type="button" class="btn btn-primary" onclick="document.getElementById('noteFile').click()">
                             <i class="fas fa-folder-open me-2"></i>Choose File
                         </button>
                     </div>
 
+                    <div class="alert alert-info mb-4">
+                        <i class="fas fa-info-circle me-2"></i>
+                        <strong>Supported file types:</strong> PDF, Word (.doc, .docx), Excel (.xlsx, .xls), text files (.txt, .md, .json, .csv, .xml)
+                        <br><small class="text-muted">Only text-extractable documents are allowed to ensure optimal AI processing and prevent RAG corruption.</small>
+                    </div>
+
                     <div id="file-info" class="d-none mb-4">
                         <div class="alert alert-info">
                             <i class="fas fa-file me-2"></i>
@@ -46,25 +52,32 @@
             </div>
 
             <div class="row mt-5">
-                <div class="col-md-4">
+                <div class="col-md-3">
                     <div class="text-center">
                         <i class="fas fa-file-pdf fa-2x text-danger mb-2"></i>
                         <h6>PDF Files</h6>
                         <p class="text-muted small">Upload PDF documents</p>
                     </div>
                 </div>
-                <div class="col-md-4">
+                <div class="col-md-3">
                     <div class="text-center">
                         <i class="fas fa-file-word fa-2x text-primary mb-2"></i>
                         <h6>Word Documents</h6>
                         <p class="text-muted small">DOC & DOCX files</p>
                     </div>
                 </div>
-                <div class="col-md-4">
+                <div class="col-md-3">
                     <div class="text-center">
-                        <i class="fas fa-file-alt fa-2x text-success mb-2"></i>
+                        <i class="fas fa-file-excel fa-2x text-success mb-2"></i>
+                        <h6>Excel Files</h6>
+                        <p class="text-muted small">XLSX & XLS files</p>
+                    </div>
+                </div>
+                <div class="col-md-3">
+                    <div class="text-center">
+                        <i class="fas fa-file-alt fa-2x text-info mb-2"></i>
                         <h6>Text Files</h6>
-                        <p class="text-muted small">Plain text documents</p>
+                        <p class="text-muted small">TXT, MD, JSON, CSV, XML</p>
                     </div>
                 </div>
             </div>