expressjsHow can I use Express.js to trace requests?

Express.js is a popular web application framework for Node.js. It can be used to trace requests by using the app.use middleware. This middleware allows you to intercept every incoming request and log the request information.

For example, the following code block will log the request method, URL, and timestamp for every incoming request:

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

app.use((req, res, next) => {
    console.log(`${req.method} ${req.url} - ${Date.now()}`)
    next()
})

// ...

Output example

GET / - 1567885313863

The code above consists of three parts:

1. const express = require('express') - This imports the Express.js module.
2. app.use((req, res, next) => {...}) - This is the middleware that intercepts the request and logs the request information. req contains information about the incoming request, res contains information about the response, and next is a function that must be called to continue to the next middleware.
3. console.log(...) - This logs the request method, URL, and timestamp.

For more information about Express.js middleware, please refer to the following link:

Express.js Middleware Guide

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