Create unique download links in Raspberry Pi using Apache

For all package download and installation, I will do that under virtual environment to manage dependencies without affecting the system Python installation. The detail of creating a virtual environment can be found in my previous blog

https://cs-student.com/virtual-environment-in-raspberry-pi/

Step 1: Download package for Raspberry Pi

Open a terminal and run the following commands to ensure your system is up to date:

sudo apt update
sudo apt upgrade

Install the Apache web server:

sudo apt install apache2

Install PHP, to handle download:

sudo apt install php libapache2-mod-php

Step 2: Configuration

The default web directory is /var/www/html. Create a directory for the downloadable files:

sudo mkdir /var/www/html/downloads

Set permissions for the download directory:

sudo chown -R www-data:www-data /var/www/html/downloads

Place any files available for download in the /var/www/html/downloads directory SCP, FTP, or directly on the Raspberry Pi.

Create a new PHP script to handle generating unique download links:

sudo nano /var/www/html/generate_link.php

Codes:

<?php
session_start();

// List of files with unique identifiers
$files = [
    "file1.zip" => "file1_unique_id",
    "file2.zip" => "file2_unique_id",
    // Ensure you have actual files in the 'downloads' directory
];

// Function to generate a random string
function generateRandomString($length = 8) {
    return substr(str_shuffle(str_repeat('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ceil($length / strlen('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')))), 1, $length);
}

// Check if a file is requested
if (isset($_GET['file'])) {
    $randomString = $_GET['file'];

    if (isset($_SESSION[$randomString])) {
        $uniqueId = $_SESSION[$randomString];
        $originalFile = array_search($uniqueId, $files);
        
        if ($originalFile && file_exists("downloads/$originalFile")) {
            header('Content-Description: File Transfer');
            header('Content-Type: application/octet-stream');
            header('Content-Disposition: attachment; filename="' . basename($originalFile) . '"');
            header('Expires: 0');
            header('Cache-Control: must-revalidate');
            header('Pragma: public');
            header('Content-Length: ' . filesize("downloads/$originalFile"));
            readfile("downloads/$originalFile");
            exit;
        } else {
            echo "File not found.";
        }
    } else {
        echo "Invalid download link.";
    }
} else {
    $randomString = generateRandomString();

    if (empty($files)) {
        echo "No files available for download.";
        exit;
    }

    $fileCount = count($files);
    $fileIndex = rand(0, $fileCount - 1);
    $fileName = array_keys($files)[$fileIndex];
    $uniqueId = $files[$fileName];

    if (!empty($fileName) && !empty($uniqueId)) {
        $_SESSION[$randomString] = $uniqueId;
        echo "Your download link: <a href='generate_link.php?file=" . htmlspecialchars($randomString) . "'>" . "http://192.168.2.230/" . htmlspecialchars($randomString) . "</a>";
    } else {
        echo "Error: Selected file or unique ID is empty.";
    }
}
?>

Navigate to http://192.168.2.230/generate_link.php. This will generate a unique download link for the file such as .

Your download link: http://192.168.2.230/Uyb8N7Lf

When the generated link is clicked, it take me to the appropriate file for download.

Create unique download links in Raspberry Pi using Apache

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