• Implement login and signup with a password
• Use has_secure_password to hash and salt passwords

We're going to make a Rails app that covers a simple authentication flow: users can create accounts, log in, and log out.

There is some starter code in place for a Rails API backend and a React frontend. To get set up, run:

$ bundle install
$ npm install --prefix client

You can work on this lab by running the tests with learn test. It will also be helpful to see what's happening during the request/response cycle by running the app in the browser. You can run the Rails server with:

$ rails s

And you can run React in another terminal with:

$ npm start --prefix client

You don't have to make any changes to the React code to get this lab working.

Our app has three pages:

1. A signup page, where the user enters their username, password, and password confirmation.
2. A login page, where the user submits their username and password and are then logged in.
3. A user homepage, which says, "Welcome, ${username}!"

Users should not be able to log in if they enter an incorrect password.

Note: we're not covering password validations in this lab, so don't worry about those. Password validation is hard to get right anyway — it's surprisingly easy to produce rules that decrease password security rather than enhance it.

To complete the lab and get the tests passing, you will need to:

• Create a User model, and migrations for a users table with username and password_digest columns. Make sure to use password_digest, not password, in your migration, and to include the has_secure_password macro in your model.

• Create a UsersController with a create method that responds to a POST /signup request. It should: create a new user; save their hashed password in the database; save the user's ID in the session hash; and return the user object in the JSON response.

• Add a show method to your UsersController that responds to a GET /me request. If the user is authenticated, return the user object in the JSON response.

• Create a Sessions controller with a create action for logging in that responds to a POST /login request, and a destroy action for logging out that responds to a DELETE /logout request.

Happy coding!

• has_secure_password