section3.13.md

Section 3.13: Custom middleware in Express

In Express, you can define middlewares that can be used for checking requests or setting some headers in response.

// Custom Middleware signature
app.use(function(req, res, next){ }); 

/*
The following code adds user to the request object and pass the control to the next 
matching route.

*/

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

//each request will pass through it
app.use(function(req, res, next){
  req.user = 'Morol';
  next(); // it will pass the control to next matching route
});

app.get('/', function(req, res){
  let user = req.user;
  console.log(user); // Morol
  return res.send(user);
});

app.listen(3000);