Express.js CRUD application with:


MongoDB (Mongoose) backend
Video & PDF upload
Course and Lecture model
EJS frontend templates


Open command prompt and create project folder by using following commands :-



mkdir  course-app



cd  course-app



and then type :-

npm init -y

and then  

Install dependencies


npm install express mongoose multer ejs dotenv method-override


then you will see your project folder like this :-





create config folder and create following file:-

File Upload Setup

multer.js  file code:-

const multer = require('multer');

const path = require('path');



const storage = multer.diskStorage({

  destination: function (req, file, cb) {

    cb(null, 'public/uploads/');

  },

  filename: function (req, file, cb) {

    cb(null, Date.now() + path.extname(file.originalname));

  }

});



module.exports = multer({ storage: storage });


and create .env file :-

MONGO_URI=mongodb://localhost:27017/courseApp



step 1: create models folder and inside it create two files 

Models

Course.js file:-



const mongoose = require('mongoose');



const CourseSchema = new mongoose.Schema({

  title: String,

  description: String,

});



module.exports = mongoose.model('Course', CourseSchema);



Lecture.js file:-


const mongoose = require('mongoose');

const LectureSchema = new mongoose.Schema({
  courseId: { type: mongoose.Schema.Types.ObjectId, ref: 'Course' },
  title: String,
  videoUrl: String,
  notesUrl: String,
});

module.exports = mongoose.model('Lecture', LectureSchema);


Step 2:-
create routes folder and inside it create courseRoutes.js  and lectureRoutes.js file :-

Routes
courseRoutes.js file code :-

const express = require('express');
const router = express.Router();
const Course = require('../models/Course');
const Lecture = require('../models/Lecture');

// List all courses
router.get('/', async (req, res) => {
  const courses = await Course.find();
  res.render('courses/index', { courses });
});

// New Course Form
router.get('/new', (req, res) => {
  res.render('courses/new');
});

// Create a new course
router.post('/', async (req, res) => {
  await Course.create(req.body);
  res.redirect('/courses');
});

// Edit Course Form (must come BEFORE '/:id')
router.get('/:id/edit', async (req, res) => {
  try {
    const course = await Course.findById(req.params.id);
    if (!course) return res.status(404).send('Course not found');
    res.render('courses/edit', { course });
  } catch (err) {
    console.error(err);
    res.status(500).send('Server Error');
  }
});

// Update Course
router.put('/:id', async (req, res) => {
  try {
    await Course.findByIdAndUpdate(req.params.id, req.body);
    res.redirect(`/courses/${req.params.id}`);
  } catch (err) {
    console.error(err);
    res.status(500).send('Update failed');
  }
});

// Delete Course (and its lectures)
router.delete('/:id', async (req, res) => {
  try {
    const courseId = req.params.id;
    await Lecture.deleteMany({ courseId }); // delete associated lectures
    await Course.findByIdAndDelete(courseId);
    res.redirect('/courses');
  } catch (err) {
    console.error(err);
    res.status(500).send('Delete failed');
  }
});

// Show course and its lectures
router.get('/:id', async (req, res) => {
  try {
    const course = await Course.findById(req.params.id);
    if (!course) return res.status(404).send('Course not found');
    const lectures = await Lecture.find({ courseId: course._id });
    res.render('courses/show', { course, lectures });
  } catch (err) {
    console.error(err);
    res.status(500).send('Error loading course');
  }
});

module.exports = router;


lectureRoutes.js file code :-


const express = require('express');
const router = express.Router();
const upload = require('../config/multer');
const Lecture = require('../models/Lecture');
const fs = require('fs');
const path = require('path');

// Show New Lecture Form
router.get('/new/:courseId', (req, res) => {
  res.render('lectures/new', { courseId: req.params.courseId });
});

// Create Lecture
router.post('/', upload.fields([{ name: 'video' }, { name: 'notes' }]), async (req, res) => {
  const { title, courseId } = req.body;
  const video = req.files['video']?.[0]?.filename || '';
  const notes = req.files['notes']?.[0]?.filename || '';

  await Lecture.create({
    title,
    courseId,
    videoUrl: '/uploads/' + video,
    notesUrl: '/uploads/' + notes,
  });

  res.redirect(`/courses/${courseId}`);
});

// Edit Lecture Form
router.get('/:id/edit', async (req, res) => {
  const lecture = await Lecture.findById(req.params.id);
  if (!lecture) return res.status(404).send('Lecture not found');
  res.render('lectures/edit', { lecture });
});

// Update Lecture
router.put('/:id', upload.fields([{ name: 'video' }, { name: 'notes' }]), async (req, res) => {
  const lecture = await Lecture.findById(req.params.id);
  if (!lecture) return res.status(404).send('Lecture not found');

  const { title } = req.body;

  if (req.files['video']) {
    if (lecture.videoUrl) fs.unlinkSync('public' + lecture.videoUrl);
    lecture.videoUrl = '/uploads/' + req.files['video'][0].filename;
  }

  if (req.files['notes']) {
    if (lecture.notesUrl) fs.unlinkSync('public' + lecture.notesUrl);
    lecture.notesUrl = '/uploads/' + req.files['notes'][0].filename;
  }

  lecture.title = title;
  await lecture.save();

  res.redirect(`/courses/${lecture.courseId}`);
});

// Delete Lecture
router.delete('/:id', async (req, res) => {
  const lecture = await Lecture.findById(req.params.id);
  if (!lecture) return res.status(404).send('Lecture not found');

  if (lecture.videoUrl) fs.unlinkSync('public' + lecture.videoUrl);
  if (lecture.notesUrl) fs.unlinkSync('public' + lecture.notesUrl);

  const courseId = lecture.courseId;
  await Lecture.findByIdAndDelete(req.params.id);

  res.redirect(`/courses/${courseId}`);
});

module.exports = router;




Step 3:-

Now create views folder and inside it create courses folder and inside courses folder create following files 


index.ejs:-


<h1>Courses</h1>

<a href="/courses/new" class="btn btn-primary mb-3">Add Course</a>

<ul class="list-group">
  <% courses.forEach(course => { %>
    <li class="list-group-item d-flex justify-content-between align-items-center">
      <div>
        <a href="/courses/<%= course._id %>" class="fw-bold text-decoration-none">
          <%= course.title %>
        </a>
      </div>
      <div>
        <a href="/courses/<%= course._id %>/edit" class="btn btn-sm btn-warning me-2">Edit</a>

        <form action="/courses/<%= course._id %>?_method=DELETE" method="POST" style="display:inline;">
          <button class="btn btn-sm btn-danger" onclick="return confirm('Delete this course?')">Delete</button>
        </form>
      </div>
    </li>
  <% }) %>
</ul>



new.ejs:-


<h1>New Course</h1>
<form action="/courses" method="POST">
  <input class="form-control" name="title" placeholder="Title"><br>
  <textarea class="form-control" name="description" placeholder="Description"></textarea><br>
  <button class="btn btn-success">Create</button>
</form>


edit.ejs:-



<h1>Edit Course</h1>

<form action="/courses/<%= course._id %>?_method=PUT" method="POST">
  <div class="mb-3">
    <label for="title" class="form-label">Course Title</label>
    <input type="text" class="form-control" name="title" id="title" value="<%= course.title %>" required>
  </div>

  <div class="mb-3">
    <label for="description" class="form-label">Description</label>
    <textarea class="form-control" name="description" id="description" rows="4"><%= course.description %></textarea>
  </div>

  <button class="btn btn-success">Update Course</button>
  <a href="/courses/<%= course._id %>" class="btn btn-secondary">Cancel</a>
</form>



show.ejs:-


<h1>Lectures for: <%= course.title %></h1>

<ul class="list-group">
  <% lectures.forEach(lec => { %>
    <li class="list-group-item">
      <div class="d-flex justify-content-between align-items-start">
        <div>
          <strong><%= lec.title %></strong><br>

          <% if (lec.videoUrl) { %>
            <video width="320" controls class="mt-2">
              <source src="<%= lec.videoUrl %>" type="video/mp4">
            </video><br>
          <% } %>

          <% if (lec.notesUrl) { %>
            <a href="<%= lec.notesUrl %>" target="_blank">Download Notes</a><br>
          <% } %>
        </div>

        <div>
          <a href="/lectures/<%= lec._id %>/edit" class="btn btn-sm btn-warning me-2">Edit</a>

          <form action="/lectures/<%= lec._id %>?_method=DELETE" method="POST" style="display:inline;">
            <button class="btn btn-sm btn-danger" onclick="return confirm('Delete this lecture?')">Delete</button>
          </form>
        </div>
      </div>
    </li>
  <% }) %>
</ul>


Step 4:-  create  lectures folder inside views folder and create following files

edit.ejs file :-

<h1>Edit Lecture</h1>
<form action="/lectures/<%= lecture._id %>?_method=PUT" method="POST" enctype="multipart/form-data">
  <input class="form-control" name="title" value="<%= lecture.title %>"><br>

  <label>Replace Video (optional):</label>
  <input class="form-control" type="file" name="video"><br>

  <label>Replace Notes (optional):</label>
  <input class="form-control" type="file" name="notes"><br>

  <button class="btn btn-success">Update Lecture</button>
</form>





new.ejs file:-

<h1>New Lecture</h1>
<form action="/lectures" method="POST" enctype="multipart/form-data">
  <input type="hidden" name="courseId" value="<%= courseId %>">
  <input class="form-control" name="title" placeholder="Lecture Title"><br>
  <label>Video:</label>
  <input class="form-control" type="file" name="video"><br>
  <label>PDF Notes:</label>
  <input class="form-control" type="file" name="notes"><br>
  <button class="btn btn-success">Upload</button>
</form>


app.js file code :-

// app.js
const express = require('express');
const mongoose = require('mongoose');
const methodOverride = require('method-override');
const path = require('path');
const dotenv = require('dotenv');
const expressLayouts = require('express-ejs-layouts'); 
const app = express();

// Load .env variables
dotenv.config();

// Connect to MongoDB
mongoose.connect(process.env.MONGO_URI || 'mongodb://localhost:27017/courseApp', {
  useNewUrlParser: true,
  useUnifiedTopology: true,
})
.then(() => console.log('✅ MongoDB Connected'))
.catch((err) => console.error('MongoDB Connection Error:', err));

// Set view engine
app.set('view engine', 'ejs');


// Middlewares
app.use(express.urlencoded({ extended: true })); // Parse form data
app.use(methodOverride('_method'));              // Support PUT/DELETE in forms
app.use(express.static(path.join(__dirname, 'public'))); // Serve static files (like uploads, CSS)

// Routes
const courseRoutes = require('./routes/courseRoutes');
const lectureRoutes = require('./routes/lectureRoutes');

app.use('/courses', courseRoutes);
app.use('/lectures', lectureRoutes);

// Home route (redirect to courses)
app.get('/', (req, res) => {
  res.redirect('/courses');
});

// Start server
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`🚀 Server running on http://localhost:${PORT}`);
});


How to Run Projects:-

open command prompt:-

cd  course-app

 and type following command to run projects:-

node app.js 









and click on course and add lectures .

and after adding open mongodb shell and check your databases :-