Completed assignment-3

week-3/.gitignore

@@ -0,0 +1 @@
+node_modules

week-3/02-course-app-easy/.gitignore

@@ -0,0 +1 @@
+node_modules

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

@@ -1,4 +1,10 @@
-const express = require('express');
+const express = require("express");
+const bcrypt = require("bcrypt");
+const jwt = require("jsonwebtoken");
+const authentication = require(__dirname + "/middleware/authentication");
+
+const jwtKey = "C@nBi-WWKTVZywQ4QNv.";
+
 const app = express();
 
 app.use(express.json());
@@ -7,48 +13,189 @@ let ADMINS = [];
 let USERS = [];
 let COURSES = [];
 
+let adminId = 1;
+let courseId = 1;
+let userId = 1;
+
 // Admin routes
-app.post('/admin/signup', (req, res) => {
+app.post("/admin/signup", async (req, res) => {
   // logic to sign up admin
+  try {
+    const { username, password } = req.body;
+    const { _, exists } = await checkIfExists(ADMINS, {
+      username,
+      password,
+    });
+    if (exists)
+      return res.status(400).send({ message: "Admin already exists" });
+    const hashedPassword = await bcrypt.hash(password, 10);
+    const admin = { id: adminId, username, password: hashedPassword };
+    if (ADMINS.length === 0) ADMINS[0] = admin;
+    else ADMINS = [...ADMINS, admin];
+    adminId++;
+    return res.status(201).send({ message: "Admin created successfully" });
+  } catch (err) {
+    return res
+      .status(500)
+      .send({ message: `Failed to signup due to the error: ${err}` });
+  }
 });
 
-app.post('/admin/login', (req, res) => {
+app.post("/admin/login", async (req, res) => {
   // logic to log in admin
+  try {
+    const { user, exists } = await checkIfExists(ADMINS, { ...req.headers });
+    if (!exists)
+      return res.status(401).send({ message: "Authentication failed" });
+    const token = jwt.sign({ userId: user.adminId }, jwtKey, {
+      expiresIn: "1h",
+    });
+    return res.status(200).send({ message: "Logged in successfully", token });
+  } catch (err) {
+    return res
+      .status(500)
+      .send({ message: `Logged in failed with error: ${err}` });
+  }
 });
 
-app.post('/admin/courses', (req, res) => {
-  // logic to create a course
+app.post("/admin/courses", authentication, (req, res) => {
+  try {
+    // logic to create a course
+    const course = { courseId, ...req.body };
+    if (COURSES.length === 0) COURSES = [course];
+    else COURSES = [...COURSES, course];
+    courseId++;
+    return res.status(200).send({
+      message: "Course created successfully",
+      courseId: course.courseId,
+    });
+  } catch (err) {
+    return res
+      .status(500)
+      .send({ message: `Course creation failed with error: ${err} ` });
+  }
 });
 
-app.put('/admin/courses/:courseId', (req, res) => {
+app.put("/admin/courses/:courseId", authentication, (req, res) => {
   // logic to edit a course
+  try {
+    const courseId = +req.params.courseId;
+    const updateCourse = { courseId, ...req.body };
+    COURSES = [
+      ...COURSES.filter((course) => course.courseId !== courseId),
+      updateCourse,
+    ];
+    res.status(200).send({ message: "Course updated successfully" });
+  } catch (error) {
+    return res.status(500).send({
+      message: `Failed to update course with courseId: ${+req.params
+        .courseId} with error: ${error}`,
+    });
+  }
 });
 
-app.get('/admin/courses', (req, res) => {
+app.get("/admin/courses", authentication, (req, res) => {
   // logic to get all courses
+  try {
+    res.status(200).send({ courses: COURSES });
+  } catch (error) {
+    return res
+      .status(500)
+      .send({ message: `Failed to get all courses with error: ${error}` });
+  }
 });
 
 // User routes
-app.post('/users/signup', (req, res) => {
+app.post("/users/signup", async (req, res) => {
   // logic to sign up user
+  try {
+    const { username, password } = req.body;
+    const { _, exists } = await checkIfExists(USERS, { username, password });
+    if (exists) return res.status(400).send({ message: "User already exists" });
+    const hashedPassword = await bcrypt.hash(password, 10);
+    const user = { id: userId, username, password: hashedPassword };
+    if (USERS.length == 0) USERS[0] = user;
+    else USERS = [...USERS, user];
+    userId++;
+
+    return res.status(201).send({ message: "User created successfully" });
+  } catch (error) {
+    return res
+      .status(500)
+      .send({ message: `Signup failed with error: ${error}` });
+  }
 });
 
-app.post('/users/login', (req, res) => {
+app.post("/users/login", async (req, res) => {
   // logic to log in user
+  try {
+    const { user, exists } = await checkIfExists(USERS, { ...req.headers });
+    if (!exists)
+      return res.status(400).send({ message: "Authentication failed" });
+    const token = jwt.sign({ userId: user.userId }, jwtKey, {
+      expiresIn: "1h",
+    });
+    return res.status(200).send({ message: "Logged in successfully", token });
+  } catch (error) {
+    return res
+      .status(500)
+      .send({ message: `Login failed with error: ${error}` });
+  }
 });
 
-app.get('/users/courses', (req, res) => {
+app.get("/users/courses", authentication, (req, res) => {
   // logic to list all courses
+  try {
+    return res.status(200).send({ courses: COURSES });
+  } catch (error) {
+    return res.status(500).send({
+      message: `Request to get all courses failed with error: ${error}`,
+    });
+  }
 });
 
-app.post('/users/courses/:courseId', (req, res) => {
+app.post("/users/courses/:courseId", authentication, (req, res) => {
   // logic to purchase a course
+  try {
+    const courseId = +req.params.courseId;
+    const course = COURSES.find((course) => +course.courseId === courseId);
+    if (!course)
+      return res.status(400).send({
+        message: "Unable to purchase course as course does not exist",
+      });
+    course.purchased = true;
+    COURSES = [
+      ...COURSES.filter((course) => +course.courseId !== courseId),
+      course,
+    ];
+    return res.status(200).send({ message: "Course purchased successfully" });
+  } catch (error) {
+    return res
+      .status(500)
+      .send({ message: `Failed to get course with error ${error}` });
+  }
 });
 
-app.get('/users/purchasedCourses', (req, res) => {
+app.get("/users/purchasedCourses", authentication, (req, res) => {
   // logic to view purchased courses
+  try {
+    const purchasedCourses = COURSES.filter((course) => course.purchased);
+    return res.status(200).send(purchasedCourses);
+  } catch (error) {
+    return res.status(500).send({
+      message: `Failed to get purchased courses with error: ${error}`,
+    });
+  }
 });
 
 app.listen(3000, () => {
-  console.log('Server is listening on port 3000');
+  console.log("Server is listening on port 3000");
 });
+
+const checkIfExists = async (arr, { username, password }) => {
+  const user = arr.find((user) => user.username === username);
+  //console.log(`User: ${JSON.stringify(user)}`);
+  if (!user) return { user, exists: false };
+  const passwordMatch = await bcrypt.compare(password, user.password);
+  return { user, exists: passwordMatch };
+};

week-3/02-course-app-easy/middleware/authentication.js

@@ -0,0 +1,16 @@
+const jwt = require("jsonwebtoken");
+const jwtKey = "C@nBi-WWKTVZywQ4QNv.";
+
+const verifyToken = (req, res, next) => {
+  const token = req.header("Authorization");
+  if (!token) return res.status(401).send({ error: "Access denied" });
+  try {
+    const decoded = jwt.verify(token, jwtKey);
+    req.userId = decoded.userId;
+    next();
+  } catch (err) {
+    res.status(401).send({ error: "Invalid token" });
+  }
+};
+
+module.exports = verifyToken;