Url Shortener 🔗

Instructions

• Fork and clone this repository to your Development folder.

After forking the repository, you will find a fully functional url shortener!

The goal is to prevent any unauthorized user from using our service.

Signup

Signup Controller

1. Install bcrypt and require it in users.controllers.
2. In users.controllers, implement the following inside the signup controller:
   • Hash the password with 10 salt rounds and overwrite req.body.password with the new, hashed password.
   • Pass the body of the request to User.create.
   • Change the response status to 201 and end it with a message.
3. Test your route in Postman.

Generating a Token

Generate and return a token in users.controllers's signup function.

1. Install jsonwebtoken.
2. Require jwt from jsonwebtoken at the top of users.controllers.
3. In users.controllers, create a function called generateToken that takes user as an argument.
4. In this function, create an object called payload and pass it the user's username and _id that's coming from user.
5. After creating your payload object, call jwt.sign() and pass it two arguments:
   1. payload
   2. JWT_SECRET
6. Add an object as a third parameter to the jwt.sign() function that has a expiresIn key and its value is the token's duration from the JWT_TOKEN_EXP variable.
7. In the signup function, after creating the user call generateToken and pass it the new user.
8. Save the returned value in a variable called token and send it as a response (json object should have a key of token with an encoded string as its value).
9. Test your route in Postman.

Signin

Passport Setup

1. Install passport and passport-local.
2. Require passport in app.js.
3. Call the app.use method and pass it passport.initialize().

Local Strategy

1. In middleware, create a file called passport.js.
2. Require LocalStrategy from passport-local.
3. Create a variable called localStrategy that's equal to a LocalStrategy instance.
4. Pass LocalStrategy an asynchronous function as an argument. This function receives three parameters: username, password and done.
5. Add a try catch statement in the function. In the catch block, call done and pass it error.
6. Look for a user in the User model that has the username that's passed to the local strategy. Save it in a variable called user.
7. Don't forget to import User.
8. Import bcrypt.
9. If user exists, call bcrypt.compare() and pass it password and user.password for comparison.
10. Save the returned value in a variable called passwordsMatch.
11. If user doesn't exist, set passwordsMatch to false.
12. If passwordsMatch is true, return done() and pass it two arguments, null and user.
13. Else, return done() and pass it two arguments, null and false.
14. In app.js, require the localStrategy instance that we just created.
15. Under the passport initialization, call passport.use() and pass it localStrategy.
16. In the /signin route, call passport.authenticate() and pass it "local" and { session: false } as arguments.

Signin Controller

Generate a token a token in users.controllers's signin function.

1. In the signin function, call generateToken and pass it the user object obtained from passport middleware.
2. Save the returned value in a variable called token and send it as a response (json object should have a key of token with an encoded string as its value).
3. Test your route in Postman.

Authentication

JWT Strategy

1. Start with installing the JWT strategy.
2. In middleware/passport.js require JWTStrategy.
3. We will create a JWT strategy instance, which takes two arguments, an options object and a callback function.
4. Tokens can be extracted from the request in many ways. We will pass our token in the request's authorization header with the scheme bearer. We need to require fromAuthHeaderAsBearerToken.
5. Now we will pass this function to our options object. Also, we will pass our JWT_SECRET for the key secretOrKey.
6. Now the second argument, an asynchronous callback function, takes two arguments, the token's payload and done function. So the JWT strategy decodes the token and passes the payload as an argument.
7. Check if the token is expired or not by comparing the expiration date to the date right now. If the token is expired, call done and pass it null and false as arguments, which will throw a 401 error.
8. If the token is not expired, we will find the user with the ID saved in the token. You can use findOne and pass it the username. Then we will pass the found user to done. If no user is found, it will throw a 401 error.
9. Let's initialize our strategy in app.js. Require jwtStrategy and pass it to passport.use().

Authenticating Users

1. In urls.routes we will restrict the shorten endpoint to only allow authenticated users to create shortened urls. Start by requiring passport in users.routes
2. In the /shorten/:userId route, call passport.authenticate() and pass it "jwt" and { session: false } as arguments.
3. Remove the /:userId param from the route.
4. In the urls.controllers, modify the shorten function to use req.user instead of the route param.
5. Test your endpoint in Postman.

Permissions

1. In the urls.routes, call passport.authenticate() and pass it "jwt" and { session: false } as arguments in the delete endpoint.
2. In the urls.controllers's deleteUrl function, add a condition that will compare the ids of the user making the request, and the id of the user that created the instance. In the condition, only allow the user who created the url to delete the url.
3. Return an authorized status and message to the user if they are attempting to delete the url and if they are not the creator!