Intro
So we installed NodeJS on our machine.
We also learned how to create a simple server using express.
Now we want to learn how to add additional middleware to our express server.
Reuse our simple server from the last article
- Open your terminal
- Create a file named
index.js:
touch index.js - Add this JavaScript code into it:
const express = require('express'); const app = express(); const PORT = 8080; app.get('/', (request, response) => { response.send('Hello World'); }); app.listen(PORT, () => { console.log(`Server running at: http://localhost:${PORT}/`); }); Note: This is our starting point, we have one working route.
I updated req to request & res to response to increase readability.
Additional Middleware
What is Middleware?
Sometimes you want to add additional functionality between the default request-response-cycle. Let's say you want to get some detailed information about the current request.
You can write a simple middleware, that handles this task, and add it to your express app.
Create a Middleware
- Create a file named
logger.js:
touch logger.js - Add this JavaScript code into it:
const logger = (req, res, next) => { console.log(`Time: ${new Date()} - Method: ${req.method} - Path: ${req.originalUrl}`); next(); }; module.exports = logger; - Require the new logger in index.js and use the middleware:
// import express (after npm install express) const express = require('express'); // import the logger const logger = require('./logger'); // create new express app and save it as app const app = express(); // server configuration const PORT = 8080; // use the middleware app.use(logger); // create a route for the app app.get('/', (req, res) => { res.send('Hello World'); }); // make the server listen to requests app.listen(PORT, () => { console.log(`Server running at: http://localhost:${PORT}/`); }); Run it from the terminal
- Run it:
node index.js Visit: http://localhost:8080
Console Result:
Server running at: http://localhost:8080/ Time: Tue Sep 03 2019 17:32:30 GMT+0200 (Central European Summer Time) - Method: GET - Path: / Series on Express and PostgreSQL
Here you can find my series about Express and PostgreSQL
Further Reading
Questions
- What's your favorite middleware for express?
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