Building an App Step 2: User Authentication

Welcome to the second step of our tutorial on building an app. In this section, we will focus on implementing user authentication to ensure that only authorized users can access sensitive information or functionalities of your application.

Key Concepts

• Authentication: The process of verifying the identity of a user.
• Authorization: The process of granting or denying access to resources based on the user's identity.

Steps to Implement User Authentication

1. Choose an Authentication Method: There are several methods to authenticate users, such as:

   • Password-based authentication: Using a username and password.
   • Two-factor authentication (2FA): Adding an additional layer of security, such as a verification code sent to the user's phone.
   • OAuth: An open standard for authorization.

2. Set Up the Backend: You will need to create an endpoint that handles user authentication. This endpoint will receive the user's credentials and validate them against your database.

3. Secure the Backend: Ensure that the communication between the client and the server is encrypted using HTTPS.

4. Create a Login Page: Design a user-friendly login page where users can enter their credentials.

5. Store User Sessions: After successful authentication, store a session token on the server and send it back to the client. This token will be used to identify the user on subsequent requests.

Example: Password-based Authentication

Let's go through a simple example of password-based authentication using a hypothetical app.

1. User Registers: When a new user signs up, they provide a username and password. Store these credentials securely in your database.

2. User Logs In: When the user logs in, they enter their username and password. Your authentication endpoint will check these credentials against the stored values.

3. Generate a Session Token: If the credentials are correct, generate a session token and send it back to the client.

4. Client Stores the Token: The client stores the session token in a secure location, such as local storage.

5. Client Makes Subsequent Requests: For subsequent requests, the client includes the session token in the request header. The server will validate the token and grant access if it is valid.

Resources

For more information on user authentication, check out our Authentication Guide.

Security