Adding Middleware for Processing Requests in Express JS
Middleware are functions that have access to incoming requests and outgoing responses in your Express application. They allow you to perform common tasks across multiple routes or the entire application, such as logging, authentication, and error handling.
Middleware is registered using the app.use() method. The order of middleware execution matters: they are called in the order they are registered.
Here’s an example of a middleware function that logs incoming requests:
Middleware can not only log requests but also modify them before they reach the route handler. For example, a middleware can be used to parse incoming JSON data:
app.use(express.json()); // Parse incoming JSON requests automatically
app.use((req, res, next) => {
console.log(`${req.method} ${req.url}`);
next(); // Pass control to the next middleware or route handler
});
Getting Started with Express JS
Express JS is a versatile, minimalist web framework for NodeJS that simplifies the development of back-end applications and APIs for web and mobile applications. Its flexibility and powerful features enable you to create robust and scalable web projects with minimal code, making it a popular choice among developers. Express is released as free and open-source software under the MIT License.
Table of Content
- Installing Express JS
- Running a simple web server in Express JS
- Adding Routes for Handling request in Express JS
- Adding Parameters to Routes in Express JS
- Modularizing Routes with Express Router:
- Adding Middleware for Processing Requests in Express JS
- Adding Error Handling Middleware in Express JS