Completed backend for Course Selling App

week-3/02-course-app-easy-2/index.js

@@ -1,52 +1,185 @@
 const express = require('express');
 const app = express();
+const jwt = require('jsonwebtoken');
 
 app.use(express.json());
 
 let ADMINS = [];
 let USERS = [];
 let COURSES = [];
 
+const secretKeyAdmin = "superS3cr3tadMIn";
+const secretKeyUser = "superS3cr3tuSEr";
+
+const generateJwtAdmin = (admin) => {
+  const payload = { username: admin.username };
+  return jwt.sign(payload, secretKeyAdmin, {expiresIn : '1h'} )
+}
+
+const authenticateJwtAdmin = (req, res, next) => {
+  const authHeader = req.headers.authorization;
+
+  if(authHeader){
+    const token = authHeader.split(' ')[1];
+
+    jwt.verify(token, secretKeyAdmin, (err,admin) => {
+      if(err){
+        return res.sendStatus(403);
+      }
+
+      req.admin = admin;
+      next();
+    })
+  }
+  else{
+    res.sendStatus(401);
+  }
+}
+
+const generateJwtUser = (user) => {
+  const payload = {username: user.username};
+  return jwt.sign(payload, secretKeyUser, {expiresIn: '1h'});
+}
+
+const authenticateJwtUser = (req,res,next) => {
+  const authHeader = req.headers.authorization;
+
+  const token = authHeader.split(' ')[1];
+  jwt.verify(token, secretKeyUser, (err, user) => {
+    if(err){
+      return res.json({message: "Error"});
+    }
+
+    req.user = user;
+    next();
+  })
+}
+
 // Admin routes
 app.post('/admin/signup', (req, res) => {
   // logic to sign up admin
+  const admin = req.body;
+  const existingAdmin = ADMINS.find(a => a.username === admin.username);
+
+  if(existingAdmin){
+    res.status(403).json({message: 'Admin already exists'});
+  }
+  else{
+    ADMINS.push(admin);
+    const token = generateJwtAdmin(admin);
+    res.json({message: 'Admin created successfully', token});
+  }
 });
 
 app.post('/admin/login', (req, res) => {
   // logic to log in admin
+  const username = req.headers.username;
+  const password = req.headers.password;
+  const admin = ADMINS.find(a => a.username === username && a.password === password);
+
+  if(admin){
+    const token = generateJwtAdmin(admin);
+    res.json({message: "Logged in successfully", token});
+  }
+  else{
+    res.status(403).json({message: "Admin authentication failed"});
+  }
 });
 
-app.post('/admin/courses', (req, res) => {
+app.post('/admin/courses', authenticateJwtAdmin, (req, res) => {
   // logic to create a course
+  const course = req.body;
+  course.id = COURSES.length + 1;
+  COURSES.push(course);
+  res.json({message: "Course created successfully", courseId: course.id});
 });
 
-app.put('/admin/courses/:courseId', (req, res) => {
-  // logic to edit a course
+app.put('/admin/courses/:courseId', authenticateJwtAdmin, (req, res) => {
+  const courseId = parseInt(req.params.courseId);
+
+  const courseIndex = COURSES.findIndex(c => c.id === courseId);
+
+  if (courseIndex > -1) {
+    const updatedCourse = { ...COURSES[courseIndex], ...req.body };
+    COURSES[courseIndex] = updatedCourse;
+    res.json({ message: 'Course updated successfully' });
+  } else {
+    res.status(404).json({ message: 'Course not found' });
+  }
 });
 
-app.get('/admin/courses', (req, res) => {
+app.get('/admin/courses', authenticateJwtAdmin, (req, res) => {
   // logic to get all courses
+  res.json({courses: COURSES});
 });
 
 // User routes
 app.post('/users/signup', (req, res) => {
   // logic to sign up user
+  const user = req.body;
+  const existingUser = USERS.find(u => u.username === user.username);
+
+  if(existingUser){
+    res.status(403).json({message: "User already exists"});
+  }
+  else{
+    USERS.push(user);
+    const token = generateJwtUser(user);
+    res.json({message: "User created successfully", token});
+  }
 });
 
 app.post('/users/login', (req, res) => {
   // logic to log in user
+  const {username, password} = req.headers;
+  const user = USERS.find(u => u.username === username && u.password === password);
+
+  if(user){
+    const token = generateJwtUser(user);
+    res.json({message: "Logged in successfully", token})
+  }
+  else{
+    res.status(403).json({message: "User authentication failed"});
+  }
 });
 
-app.get('/users/courses', (req, res) => {
+app.get('/users/courses', authenticateJwtUser, (req, res) => {
   // logic to list all courses
+  res.json({courses: COURSES});
 });
 
-app.post('/users/courses/:courseId', (req, res) => {
+app.post('/users/courses/:courseId', authenticateJwtUser, (req, res) => {
   // logic to purchase a course
+  const courseId = parseInt(req.params.courseId);
+  const course = COURSES.find(c => c.id == courseId);
+
+  if(course){
+    const user = USERS.find(u => u.username === req.user.username);
+    if(user){
+      if(!user.purchasedCourses){
+        user.purchasedCourses = [];
+      }
+      user.purchasedCourses.push(course);
+      res.json({message: "Course purchased successfully"});
+    }
+    else{
+      res.json({message: "User not found"});
+    }
+  }
+  else{
+    res.status(404).json({message: "Course not found"});
+  }
 });
 
-app.get('/users/purchasedCourses', (req, res) => {
+app.get('/users/purchasedCourses', authenticateJwtUser, (req, res) => {
   // logic to view purchased courses
+  const user = USERS.find(u => u.username === req.user.username);
+  if(user && user.purchasedCourses){
+    res.json({purchasedCourses: user.purchasedCourses});
+  }
+  else{
+    res.status(404).json({message: "No courses purchased"})
+  }
 });
 
 app.listen(3000, () => {