How do I integrate middleware with a framework?

How do I integrate middleware with a framework?

Integrating middleware with a framework typically involves adding middleware functions to the request-response cycle. Which framework are you using?

I'm using Express.js. Can you give me a code example?

Sure! In Express.js, you can use middleware like this:

const express = require('express');
const app = express();

const myMiddleware = (req, res, next) => {
    console.log('Middleware executed!');
    next();
};

app.use(myMiddleware);

app.get('/', (req, res) => {
    res.send('Hello World!');
});

app.listen(3000, () => {
    console.log('Server is running on port 3000');
});

This code sets up a simple middleware that logs a message before proceeding to the next handler.

What other types of middleware can I use?

You can use various types of middleware in Express.js, such as:

1. Body parsers (e.g., body-parser)
2. Cookie parsers (e.g., cookie-parser)
3. Session management (e.g., express-session)
4. Error handling middleware
5. CORS middleware (e.g., cors)

Each serves different purposes, like parsing request bodies or managing sessions.

How do I handle errors with middleware?

To handle errors in Express.js, you can define an error-handling middleware function. It should have four parameters: err, req, res, and next. Here's an example:

app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).send('Something broke!');
});