PHP Miscellaneous

Misc Function Categories

🔹 System Information Functions

Retrieve information about your PHP installation, server environment, and operating system. These functions are useful for debugging and compatibility checks.

<?php
// PHP version
echo "PHP Version: " . phpversion() . "\n";
echo "PHP Major Version: " . PHP_MAJOR_VERSION . "\n";
echo "PHP Minor Version: " . PHP_MINOR_VERSION . "\n\n";

// Operating system info
echo "OS: " . php_uname('s') . "\n";
echo "Hostname: " . php_uname('n') . "\n";
echo "OS Version: " . php_uname('r') . "\n\n";

// Check if extension is loaded
echo "JSON extension: " . (extension_loaded('json') ? "Loaded" : "Not loaded") . "\n";
echo "MySQL extension: " . (extension_loaded('mysqli') ? "Loaded" : "Not loaded");
?>

🔹 Generating Unique IDs

Create unique identifiers for database records, session tokens, file names, and temporary data. PHP offers several methods with different levels of uniqueness.

<?php
// Basic unique ID (based on time)
echo "uniqid(): " . uniqid() . "\n";

// Unique ID with prefix
echo "uniqid('user_'): " . uniqid('user_') . "\n";

// More unique (with more entropy)
echo "uniqid('', true): " . uniqid('', true) . "\n\n";

// Random bytes (cryptographically secure)
$bytes = random_bytes(16);
echo "Random hex: " . bin2hex($bytes) . "\n\n";

// UUID-like identifier
function generateUUID() {
    $data = random_bytes(16);
    $data[6] = chr(ord($data[6]) & 0x0f | 0x40);
    $data[8] = chr(ord($data[8]) & 0x3f | 0x80);
    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
}
echo "UUID: " . generateUUID();
?>

🔹 Sleep and Delay Functions

Pause script execution for a specified time. Use sleep() for seconds, usleep() for microseconds, or time_sleep_until() to sleep until a specific timestamp.

<?php
echo "Start: " . date('H:i:s') . "\n";

// Sleep for 2 seconds
sleep(2);
echo "After 2 seconds: " . date('H:i:s') . "\n";

// Sleep for 500,000 microseconds (0.5 seconds)
usleep(500000);
echo "After 0.5 more seconds: " . date('H:i:s') . "\n\n";

// Sleep until specific time
$wake_time = time() + 1;
echo "Sleeping until: " . date('H:i:s', $wake_time) . "\n";
time_sleep_until($wake_time);
echo "Awake at: " . date('H:i:s');
?>

🔹 Connection Handling

Monitor and control client connections to your PHP scripts. These functions help handle situations where users close their browser or connection drops.

<?php
// Check connection status
$status = connection_status();
switch ($status) {
    case CONNECTION_NORMAL:
        echo "Connection: Normal\n";
        break;
    case CONNECTION_ABORTED:
        echo "Connection: Aborted by user\n";
        break;
    case CONNECTION_TIMEOUT:
        echo "Connection: Timeout\n";
        break;
}

// Check if connection was aborted
if (connection_aborted()) {
    echo "User disconnected!\n";
} else {
    echo "User still connected\n";
}

// Continue script even if user disconnects
ignore_user_abort(true);
echo "Script will continue even if user closes browser";
?>

🔹 Defining Constants

Create constants that cannot be changed during script execution. Use define() for simple constants or const for class constants and better performance.

<?php
// Define constants
define("SITE_NAME", "My Website");
define("MAX_USERS", 100);
define("DEBUG_MODE", true);

echo "Site: " . SITE_NAME . "\n";
echo "Max users: " . MAX_USERS . "\n";
echo "Debug: " . (DEBUG_MODE ? "On" : "Off") . "\n\n";

// Check if constant exists
if (defined("SITE_NAME")) {
    echo "SITE_NAME is defined\n";
}

// Case-insensitive constant (deprecated in PHP 7.3+)
define("VERSION", "1.0.0");
echo "Version: " . VERSION . "\n\n";

// Get all defined constants
$constants = get_defined_constants(true);
echo "User constants: " . count($constants['user']);
?>

🔹 Script Execution Control

Control how long scripts can run and how much memory they can use. These functions help prevent scripts from consuming too many server resources.

<?php
// Get current time limit
echo "Current time limit: " . ini_get('max_execution_time') . " seconds\n";

// Set time limit to 60 seconds
set_time_limit(60);
echo "New time limit: 60 seconds\n\n";

// Get memory limit
echo "Memory limit: " . ini_get('memory_limit') . "\n";

// Get current memory usage
echo "Memory used: " . round(memory_get_usage() / 1024 / 1024, 2) . " MB\n";
echo "Peak memory: " . round(memory_get_peak_usage() / 1024 / 1024, 2) . " MB\n\n";

// Disable time limit (use carefully!)
set_time_limit(0);
echo "Time limit disabled (infinite execution)";
?>

🔹 Packing and Unpacking Data

Convert data between binary and other formats using pack() and unpack(). This is useful for reading binary files, network protocols, and low-level data manipulation.

<?php
// Pack integers into binary string
$packed = pack("C3", 65, 66, 67);
echo "Packed: " . bin2hex($packed) . "\n";

// Unpack binary data
$unpacked = unpack("C3", $packed);
echo "Unpacked: ";
print_r($unpacked);
echo "\n";

// Pack string
$text = pack("A10", "Hello");
echo "Packed text: '$text'\n";
echo "Length: " . strlen($text) . "\n\n";

// Convert between formats
$number = 1234;
$hex = dechex($number);
$binary = decbin($number);
echo "Decimal: $number\n";
echo "Hex: $hex\n";
echo "Binary: $binary";
?>

🔹 Useful Utility Functions

Miscellaneous helper functions for common tasks like highlighting PHP code, evaluating strings as code, and getting function information.

<?php
// Highlight PHP syntax
$code = '<?php echo "Hello World"; ?>';
echo "Highlighted code:\n";
echo highlight_string($code, true) . "\n\n";

// Get list of defined functions
$functions = get_defined_functions();
echo "Built-in functions: " . count($functions['internal']) . "\n";
echo "User functions: " . count($functions['user']) . "\n\n";

// Check if function exists
if (function_exists('strlen')) {
    echo "strlen() exists\n";
}

// Get function arguments
function greet($name, $age = 18) {
    return "Hello $name, age $age";
}

$reflection = new ReflectionFunction('greet');
echo "greet() has " . $reflection->getNumberOfParameters() . " parameters";
?>

🔹 Practical Examples

Real-world applications combining miscellaneous functions for common programming tasks like generating tokens, rate limiting, and system monitoring.

<?php
// Generate secure token
function generateToken($length = 32) {
    return bin2hex(random_bytes($length / 2));
}
echo "Secure token: " . generateToken(16) . "\n\n";

// Simple rate limiter
function rateLimiter($key, $max_requests = 5, $period = 60) {
    static $requests = [];
    $now = time();
    
    if (!isset($requests[$key])) {
        $requests[$key] = [];
    }
    
    // Remove old requests
    $requests[$key] = array_filter($requests[$key], function($time) use ($now, $period) {
        return ($now - $time) < $period;
    });
    
    if (count($requests[$key]) >= $max_requests) {
        return false;
    }
    
    $requests[$key][] = $now;
    return true;
}

echo "Request 1: " . (rateLimiter('user123') ? "Allowed" : "Blocked") . "\n";
echo "Request 2: " . (rateLimiter('user123') ? "Allowed" : "Blocked");
?>