PHP Supergloblal variables

In PHP superglobal variables are most used when it comes to focus over development of server-side rendering websites. In this article we are going to be talking about Superglobal variables in PHP. literally superglobal variables are predefined variables in PHP which can be accessed from any scpoe within a PHP script. These are literally called "Superglobal" because they are always available for the further usage and specific purposes. PHP literally provides kind of these variables for various purposes and they store various types of information, such as form input, server and environment details, session information, and more. In this article we are going to talk about all the variables which are known as Superglobal variables and the usage of each one there is.

1. $_GET
2. $_POST
3. $_REQUEST
4. $_SESSION
5. $_COOKIE
6. $_SERVER
7. $_FILES
8. $_ENV

$_GET:
We use get superglobal variable in PHP to retrive the values from the query string in a URL. Like the date can be passed from the script via the URL parameters. Like When a URL contains query parameters, such as http://example.com/?name=John&age=25, you can access those values using the $_GET superglobal variable.

$_POST:
Used to gather data from an HTML form and pass the variables.

$_REQUEST:
It is also used to collect data after submitting an HTML form like it
Combines the values of $_GET, $_POST, and $_COOKIE superglobals into one array. It can be used to access data from both GET and POST requests, but be cautious with this variable as it may lead to security vulnerabilities if not used correctly.

$_SESSION:

Contains variables that are stored and accessible across multiple requests and sessions. It allows you to store and retrieve data specific to a particular user throughout their interaction with your website or web application.

$_COOKIE:
Contains variables sent to the current script via HTTP cookies. It provides access to the values stored in cookies set by the server or by the client-side JavaScript code.

$_SERVER:
Contains information about the locations of headers, paths and
scripts and contains information about the server and the execution environment. It includes details like the current script's filename, server name, request method, and more.

$_FILES:
Contains information about uploaded files through the HTTP POST method with the enctype attribute set to "multipart/form-data". It provides access to the file name, type, size, and temporary location of the uploaded file.

$_ENV:
Contains variables from the server's environment. It provides access to variables set by the server or the system environment.

These superglobal variables can be accessed and manipulated like regular arrays. For example, $_GET['name'] retrieves the value of the "name" parameter in the URL. However, it's essential to validate, sanitize, and properly handle the data in these superglobals to ensure security and prevent vulnerabilities like SQL injection or cross-site scripting (XSS).

Superglobals in PHP offer a convenient way to access various types of data across different scopes, making it easier to interact with user input, server environment, session data, and more.

How to use PHP superglobal variables:

Well you can keep an eye over these examples that how we use PHP superglobal variables:

<?php
// Example of $_GET
if (isset($_GET['name'])) {
    $name = $_GET['name'];
    echo "Hello, $name!";
}

// Example of $_POST
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $username = $_POST['username'];
    $password = $_POST['password'];
    // Process login/authentication
}

// Example of $_REQUEST
if (isset($_REQUEST['search'])) {
    $search_query = $_REQUEST['search'];
    // Perform search based on $search_query
}

// Example of $_SESSION
session_start();
$_SESSION['user_id'] = 123;
if (isset($_SESSION['user_id'])) {
    $user_id = $_SESSION['user_id'];
    // Use $user_id to retrieve user-specific data
}

// Example of $_COOKIE
if (isset($_COOKIE['username'])) {
    $username = $_COOKIE['username'];
    // Use $username to personalize user experience
}

// Example of $_SERVER
echo "Server IP Address: " . $_SERVER['SERVER_ADDR'];

// Example of $_FILES
if (isset($_FILES['file'])) {
    $file_name = $_FILES['file']['name'];
    $file_tmp = $_FILES['file']['tmp_name'];
    move_uploaded_file($file_tmp, "uploads/$file_name");
}

// Example of $_ENV
$database_host = $_ENV['DB_HOST'];
$database_username = $_ENV['DB_USER'];
$database_password = $_ENV['DB_PASS'];
?>

These examples demonstrate various scenarios where each superglobal variable is used in PHP to handle different aspects of web development, such as user input, session management, file uploads, environment configuration, and more.