Node.js Express Routing

Introduction to Express Routing

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications. One of its core features is routing, which allows you to define how your application responds to client requests at a particular endpoint, which is a URI (or path) and a specific HTTP request method (GET, POST, etc.).

In this guide, we'll explore how to set up basic routing in Express using GET and POST methods to handle different types of HTTP requests.

Setting Up Express

Before we dive into routing, let's quickly set up an Express application. If you haven't installed Express yet, you can do so by running the following command:

Once installed, create a new file named app.js and add the following basic setup code:

Defining GET Routes

The app.get() function is used to define a route that listens for HTTP GET requests on the specified path. Here's a simple example:

In this example, when a GET request is made to the root URL (/), the server responds with 'Hello, World!'.

Defining POST Routes

The app.post() method is used to define a route that listens for HTTP POST requests. This is useful for handling data sent to the server, such as form submissions. Here's how you can define a POST route:

In this instance, when a POST request is sent to the /submit path, the server responds with 'Form Submitted!'.

Route Parameters

Route parameters are named URL segments that capture the values at their position in the URL. They are specified in the path of your route definition and can be accessed via the req.params object.

Here's an example of using route parameters:

In this example, if the URL /user/123 is requested, the server will respond with 'User ID: 123'.

Handling 404 Errors

It's essential to handle 404 errors in your application to provide a better user experience. You can achieve this by adding a middleware function at the end of your route definitions:

This middleware function will be executed for every request that doesn't match any of the defined routes, effectively handling 404 errors.

Conclusion

Node.js Express routing is a fundamental concept for building web applications. By mastering how to define and handle routes using GET and POST methods, you can create dynamic and responsive applications. In the next post, we will delve into Express Middleware to enhance request handling even further.