Building a Backend API for a Webflow Project Using Cloudflare Workers

In this tutorial series, we are going to build a backend API for a Webflow project using Cloudflare workers. Cloudflare workers enable us to run JavaScript applications on Cloudflare's edge network, allowing us to deploy serverless applications closer to users.

Overview

This tutorial will focus on implementing a backend API for a to-do application, covering the following topics:

1. Building a backend API for a Webflow project
2. Implementing Cloudflare workers for the API
3. Exploring the use of middleware for routing
4. Handling authentication for secure access to endpoints

Before diving into the implementation details, it’s also vital to review the previous streams to understand the context and background of the project. We have already discussed the use of Cloudflare workers, the benefits of implementing an API with Cloudflare workers, and the application we are building, which is a to-do app that allows users to create, edit, and remove to-dos.

Today, we will expand the implementation of our backend API by going deeper into how we can implement and utilize middleware and handle authentication.

Middleware and Its Role

Middleware plays a crucial role in handling requests and responses in the routing process. As we build our backend API, we will incorporate middleware to ensure that our application can check for user authentication and authorize access to specific endpoints. Middleware acts as a bridge between the incoming request and the final handler, allowing us to inject custom logic, perform checks, and control the flow of the request before it reaches the main logic implementation.

Adding Middleware for Authentication

To integrate middleware for user authentication, we will first create a simple middleware function called hello middleware in our code. The middleware function will log a message, and then pass the request to the next handler using the next function, which triggers the continuation of request processing.

async function helloMiddleware(request, next) {  console.log('Hey');  await next();}

Once the helloMiddleware has been defined, it can be added to the routing process to run before the main logic handler. By applying middleware in this manner, we can control the flow of the request and insert custom logic as needed.

Implementing Basic Authentication Checking

Next, we will focus on setting up basic authentication checks in our middleware. This involves extracting the authentication header from the request and checking for its presence to ensure that users attempting to access certain endpoints are authenticated.

async function authenticateUser(context, next) {  const authHeader = context.request.headers.get('Authentication');    if (!authHeader) {    throw new Error('Unauthorized: Missing authentication header');  } else {    const userId = authHeader.split('Bearer ')[1];        if (!userId) {      throw new Error('Unauthorized: Missing user ID');    }        context.set('userId', userId);    await next();  }}

In this middleware function authenticateUser, we extract the user ID from the authentication header and set it within the context for further processing. By using middleware in this manner, we can enforce basic authentication checks and ensure that only authenticated users proceed to access specific endpoints.

Implementing Interaction with the Authentication Middleware

After defining the middleware functions, we integrate them into the routing system to ensure that they are applied in the request processing chain. By adding the middleware to the relevant routes, such as the route for fetching to-dos, we can enforce authentication checks before executing the core logic in handling the requests.

router.get('/todos', authenticateUser, async (context) => {  const userId = context.get('userId');  // Logic to retrieve to-dos for the specific user});router.post('/todos', authenticateUser, async (context) => {  const userId = context.get('userId');  // Logic to create a new to-do for the specific user});

With the authenticateUser middleware added to the routes, it ensures that only authenticated users with valid user IDs are able to fetch or create to-dos. This helps control access to sensitive endpoints and prevents unauthorized access to the application’s resources.

Frontend Integration for User Id Generation

To synchronize the user ID generation and authentication with the frontend, we can utilize JavaScript functions to generate and retrieve the user ID from the user's local storage. By generating the user ID on the frontend and including it in the authentication headers for backend requests, we ensure a seamless flow of user authentication and access control.

function getUserID() {  let storedUserID = localStorage.getItem('userID');    if (!storedUserID) {    const newUserID = crypto.randomUUID();    localStorage.setItem('userID', newUserID);    return newUserID;  } else {    return storedUserID;  }}

By incorporating the getUserID function into the frontend code, we can ensure that user IDs are generated and used for authentication when interacting with the backend API. The user ID becomes a crucial identifier for user-specific operations in the application.

Conclusion

In this tutorial, we covered the implementation of middleware for authentication in a Webflow project using Cloudflare workers. By introducing middleware functions to enforce authentication checks, we established a basic authentication layer for securing endpoint access. Additionally, by integrating frontend functions for user ID generation and storage, we were able to seamlessly manage user authentication both at the frontend and backend levels.

Moving forward, we will dive deeper into implementing a robust and secure authentication workflow using authentication services such as Auth0 to enhance user authentication and access control in our Webflow project.

With the fundamentals of authentication and middleware in place, we are on track to create a secure and reliable backend API for our Webflow project, providing a robust foundation for managing user interactions and data persistence. Stay tuned for our next tutorial as we explore more advanced authentication strategies and its integration with Cloudflare workers for optimal performance and security.