www.mikescher.com/www/internals/utils.php

<?php

function startsWith($haystack, $needle)
{
	$length = strlen($needle);
	return (substr($haystack, 0, $length) === $needle);
}

function endsWith($haystack, $needle)
{
	$length = strlen($needle);
	return $length === 0 || (substr($haystack, -$length) === $needle);
}

function destructiveUrlEncode($str)
{
	$str = str_replace(' ', '_', $str);
	$str = str_replace('+', '_', $str);
	$str = str_replace(':', '_', $str);
	$str = str_replace('.', '', $str);
	return urlencode($str);
}

function formatMilliseconds($millis)
{
	if ($millis < 1000)
	{
		return $millis . 'ms';
	}
	else if ($millis < 10 * 1000)
	{
		return number_format($millis / (1000), 2) . 's';
	}
	else if ($millis < 60 * 1000)
	{
		return floor($millis / (1000)) . 's';
	}
	else if ($millis < 10 * 60 * 1000)
	{
		return floor($millis / (60 * 1000)) . 'min ' . floor(($millis % (60 * 1000)) / 1000) . 's';
	}
	else if ($millis < 60 * 60 * 1000)
	{
		return floor($millis / (60 * 1000)) . 'min';
	}
	else if ($millis < 10 * 60 * 60 * 1000)
	{
		return number_format($millis / (60 * 60 * 1000), 2) . ' hours';
	}
	else
	{
		return floor($millis / (60 * 60 * 1000)) . ' hours';
	}
}

/**
 * easy image resize function
 * @author http://www.nimrodstech.com/php-image-resize/
 * @param  string $file - file name to resize
 * @param  int $width - new image width
 * @param  int $height - new image height
 * @param  boolean $proportional - keep image proportional, default is no
 * @param  string $output - name of the new file (include path if needed)
 * @return boolean|resource
 */
function smart_resize_image($file, $width, $height, $proportional, $output)
{
	if ( $height <= 0 && $width <= 0 ) return false;
	if ( $file === null) return false;

	# Setting defaults and meta
	$info                         = getimagesize($file);
	$image                        = '';
	$final_width                  = 0;
	$final_height                 = 0;
	list($width_old, $height_old) = $info;
	$cropHeight = $cropWidth = 0;

	# Calculating proportionality
	if ($proportional) {
		if      ($width  == 0)  $factor = $height/$height_old;
		elseif  ($height == 0)  $factor = $width/$width_old;
		else                    $factor = min( $width / $width_old, $height / $height_old );

		$final_width  = round( $width_old * $factor );
		$final_height = round( $height_old * $factor );
	}
	else {
		$final_width = ( $width <= 0 ) ? $width_old : $width;
		$final_height = ( $height <= 0 ) ? $height_old : $height;
		$widthX = $width_old / $width;
		$heightX = $height_old / $height;

		$x = min($widthX, $heightX);
		$cropWidth = ($width_old - $width * $x) / 2;
		$cropHeight = ($height_old - $height * $x) / 2;
	}

	# Loading image to memory according to type
	switch ( $info[2] ) {
		case IMAGETYPE_JPEG:  $image = imagecreatefromjpeg($file); break;
		case IMAGETYPE_GIF:   $image = imagecreatefromgif($file);  break;
		case IMAGETYPE_PNG:   $image = imagecreatefrompng($file);  break;
		default: return false;
	}


	# This is the resizing/resampling/transparency-preserving magic
	$image_resized = imagecreatetruecolor( $final_width, $final_height );
	if ( ($info[2] == IMAGETYPE_GIF) || ($info[2] == IMAGETYPE_PNG) ) {
		$transparency = imagecolortransparent($image);
		$palletsize = imagecolorstotal($image);

		if ($transparency >= 0 && $transparency < $palletsize) {
			$transparent_color  = imagecolorsforindex($image, $transparency);
			$transparency       = imagecolorallocate($image_resized, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);
			imagefill($image_resized, 0, 0, $transparency);
			imagecolortransparent($image_resized, $transparency);
		}
		elseif ($info[2] == IMAGETYPE_PNG) {
			imagealphablending($image_resized, false);
			$color = imagecolorallocatealpha($image_resized, 0, 0, 0, 127);
			imagefill($image_resized, 0, 0, $color);
			imagesavealpha($image_resized, true);
		}
	}
	imagecopyresampled($image_resized, $image, 0, 0, $cropWidth, $cropHeight, $final_width, $final_height, $width_old - 2 * $cropWidth, $height_old - 2 * $cropHeight);

	# Preparing a method of providing result
	switch ( strtolower($output) ) {
		case 'browser':
			$mime = image_type_to_mime_type($info[2]);
			header("Content-type: $mime");
			$output = NULL;
			break;
		case 'file':
			$output = $file;
			break;
		case 'return':
			return $image_resized;
			break;
		default:
			break;
	}

	# Writing image according to type to the output destination and image quality
	switch ( $info[2] ) {
		case IMAGETYPE_GIF:   imagegif($image_resized, $output);    break;
		case IMAGETYPE_JPEG:  imagejpeg($image_resized, $output, 100);   break;
		case IMAGETYPE_PNG:
			$quality = 9 - (int)((0.9*100)/10.0);
			imagepng($image_resized, $output, $quality);
			break;
		default: return false;
	}

	return true;
}

/**
 * @param  string $file - file name to resize
 * @param  int $width - new image width
 * @param  int $height - new image height
 * @param  string $output - name of the new file (include path if needed)
 */
function magick_resize_image($file, $width, $height, $output)
{
	list($width_old, $height_old) = getimagesize($file);

	if      ($width  == 0)  $factor = $height/$height_old;
	elseif  ($height == 0)  $factor = $width/$width_old;
	else                    $factor = min( $width / $width_old, $height / $height_old );

	$final_width  = round( $width_old * $factor );
	$final_height = round( $height_old * $factor );

	$cmd = 'convert "' . $file . '" -strip -resize ' . $final_width . 'x' . $final_height . ' "' . $output . '"';

	$output=null;
	$retval=null;
	$r = exec($cmd, $output, $retval);

	if ($r === false) throw new Exception("Magick exec() return FALSE");
	if ($retval !== 0) throw new Exception("Magick exec() returned exitcode $retval");
}

function sendMail($subject, $content, $to, $from)
{
	mail($to, $subject, $content, 'From: ' . $from);
}

function get_client_ip() {
	if (getenv('HTTP_CLIENT_IP')) return getenv('HTTP_CLIENT_IP');
	else if(getenv('HTTP_X_FORWARDED_FOR')) return getenv('HTTP_X_FORWARDED_FOR');
	else if(getenv('HTTP_X_FORWARDED')) return getenv('HTTP_X_FORWARDED');
	else if(getenv('HTTP_FORWARDED_FOR')) return getenv('HTTP_FORWARDED_FOR');
	else if(getenv('HTTP_FORWARDED')) return getenv('HTTP_FORWARDED');
	else if(getenv('REMOTE_ADDR')) return getenv('REMOTE_ADDR');
	else if (isset($_SERVER['HTTP_CLIENT_IP'])) return $_SERVER['HTTP_CLIENT_IP'];
	else if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])) return $_SERVER['HTTP_X_FORWARDED_FOR'];
	else if(isset($_SERVER['HTTP_X_FORWARDED'])) return $_SERVER['HTTP_X_FORWARDED'];
	else if(isset($_SERVER['HTTP_FORWARDED_FOR'])) return $_SERVER['HTTP_FORWARDED_FOR'];
	else if(isset($_SERVER['HTTP_FORWARDED'])) return $_SERVER['HTTP_FORWARDED'];
	else if(isset($_SERVER['REMOTE_ADDR'])) return $_SERVER['REMOTE_ADDR'];
	else return 'UNKNOWN';
}

function getRandomToken($length = 32)
{
	try
	{
		if(!isset($length) || intval($length) <= 8 ) $length = 32;

		if (function_exists('random_bytes')) return bin2hex(random_bytes($length));
		if (function_exists('mcrypt_create_iv')) return bin2hex(mcrypt_create_iv($length, MCRYPT_DEV_URANDOM));
		if (function_exists('openssl_random_pseudo_bytes')) return bin2hex(openssl_random_pseudo_bytes($length));
	}
	catch (Exception $e) { throw new InvalidArgumentException($e); }

	throw new InvalidArgumentException("No random");
}

function isHTTPRequest()
{
	if (isset($_SERVER['HTTP_X_FORWARDED_PROTOCOL']) && strtolower($_SERVER['HTTP_X_FORWARDED_PROTOCOL']) === "https" ) return false;

	if (isset($_SERVER['HTTPS']) && (!empty($_SERVER['HTTPS']) || $_SERVER['HTTPS'] !== "off")) return false; 

	return true;
}

function str_max_len(string $str, int $max)
{
	if (strlen($str) < $max) return $str;

	return substr($str, 0, $max-3)."...";
}

function formatException($e)
{
	if ($e === null) return "NULL";

	if ($e instanceof Exception)
	{
		$r = '';
		$r .= $e->getMessage() . "\n\n";
		$r .= $e->getFile() . "\n\n";
		$r .= str_replace(dirname(__DIR__), '.', $e->getTraceAsString()) . "\n\n";
		if (isset($e->xdebug_message))
		{
			$xdbg = $e->xdebug_message;
			$xdbg = str_replace('<br />', "\n", $xdbg);
			$xdbg = str_replace('<br/>', "\n", $xdbg);
			$xdbg = str_replace('<br>', "\n", $xdbg);
			$xdbg = str_replace('><', "> <", $xdbg);
			$xdbg = strip_tags($xdbg);
			$r .= $xdbg . "\n";
		}
		return $r;
	}

	return 'object';
}

function array_key_map_unique(array $array, string $key)
{
	$r = [];
	foreach ($array as $d) if (!in_array($d[$key], $r)) $r []= $d[$key];
	return $r;
}

function array_key_map(array $array, string $key)
{
	$r = [];
	foreach ($array as $d) $r []= $d[$key];
	return $r;
}

function curl_http_request($url)
{
	$ch = curl_init($url);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	curl_setopt($ch, CURLOPT_TIMEOUT, 10);

	$output   = curl_exec($ch);
	$httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
	$redirect = curl_getinfo($ch, CURLINFO_REDIRECT_URL);
	$errnum   = curl_errno( $ch );
	$errmsg   = curl_error( $ch );
	curl_close($ch);

	return [ 'output'=>$output, 'statuscode'=>$httpcode, 'redirect'=>$redirect, 'errnum'=>$errnum, 'errstr'=>$errmsg ];
}

function array_last(array $arr)
{
	return $arr[count($arr)-1];
}

function explode_allow_empty(string $separator, string $str): array {
	if ($str === '') return [];
	return explode($separator, $str);
}