Comparison with long-running servers (Node.js) in PHP

Introduction

This topic helps you understand how PHP works differently from long-running servers like Node.js. It shows why PHP starts fresh for each request, while Node.js keeps running all the time.

When deciding which server technology to use for a web project.

When learning how PHP handles web requests compared to Node.js.

When troubleshooting performance or memory issues in PHP or Node.js apps.

When explaining to a friend why PHP scripts start over on every page load.

When planning how to manage resources and data in your web server.

Syntax

PHP

<?php
// PHP script runs fresh on each request
// Node.js server runs continuously
?>

PHP scripts start from zero every time a user visits a page.

Node.js servers keep running and handle many requests without restarting.

Examples

Each time this PHP script runs, $count starts at 0, so it always prints 1.

PHP

<?php
// PHP example
$count = 0;
$count++;
echo $count; // Always prints 1
?>

Node.js keeps the count variable in memory, so it increases with each request.

PHP

// Node.js example
let count = 0;
const http = require('http');
http.createServer((req, res) => {
  count++;
  res.end(`Count is ${count}`);
}).listen(3000);

Sample Program

This PHP script uses a session to remember the count between requests, simulating persistent data.

PHP

<?php
// PHP script to show count
session_start();
if (!isset($_SESSION['count'])) {
  $_SESSION['count'] = 0;
}
$_SESSION['count']++;
echo "Count is " . $_SESSION['count'];
?>

Important Notes

PHP resets all variables on each request unless you use sessions or databases.

Node.js can keep variables in memory because it runs continuously.

Using sessions in PHP is a way to keep data between requests, but it is different from a long-running server.

Summary

PHP scripts start fresh on every request, so variables reset.

Node.js servers run all the time and keep data in memory between requests.

Sessions or databases help PHP remember data across requests.