Default How can I change create_function to anonymous function? - php

Question

I am in the lengthy process of modernizing a lot of code on my website to make it php 8.x compliant. I have never really gotten the hang of user defined functions, so the following code was not created by me.
I am trying to change create_function, which has been removed as of php 8.0, to an anonymous function.
I removed the security lines as they were irrelevant.
Any hints as to how I should proceed?
Code:
print_r($_FILES)
##produces
$_FILES is Array ( [pix] => Array ( [name] => christmas every day.jpg [type] => image/jpeg [tmp_name] => /tmp/phpWPefKh [error] => 0 [size] => 91284 ) )
Here is the outdated code:
Code:
<?php
$end=substr($_FILES['pix']['name'],-3,3);
$end=strtolower($end);
if($end=="jpg"||$end=="peg"||$end=="gif"||$end=="png") {}
else {echo"<script type=\"text/javascript\">
window.location = \"http://www.animeviews.com\"
</script>";
exit;
}
function or_f($a, $b) {
return $a || $b;
}
function file_has_extension($fn, $ext) {
if(is_array($ext))
return array_reduce(array_map(create_function('$a', 'return file_has_extension(\'' . $fn . '\', $a);'), $ext), 'or_f', false);
else
return stripos($fn, '.' . strtolower($ext)) === strlen($fn) - strlen($ext) + 1;
}
$image_extensions = array(
'png',
'jpg',
'jpeg',
'gif'
);
if(!isset($_POST['Upload']) and !isset($_POST['Overwrite']))
{
include("picform.php");
} # endif
else
{
if($_FILES['pix']['tmp_name'] == "none")
{
echo "<b>File did not successfully upload. Check the
file size. File must be less than 500K.<br>";
include("picform.php");
exit();
}
if(file_has_extension($_FILES['pix']['name'], $image_extensions))
{
echo "<b>File is not a picture. Please try another
file.</b><br>";
include("picform.php");
exit();
}
else
{
$destination = $_FILES['pix']['name'];
$destination = strtolower($destination);
$temp_file = $_FILES['pix']['tmp_name'];
if (file_exists($destination) and $_POST['Overwrite']!="Overwrite") {
echo "The file $destination already exists.";exit();
}
#########
move_uploaded_file($temp_file,$destination);
echo "<p><b>The file has successfully uploaded:</b>
{$destination}
({$_FILES['pix']['size']})</p>";
$img="http://www.animeviews.com/images/$destination";
$img = $destination;
$width = "180px";
$height = "";
// Get new dimensions
list($width1, $height1) = getimagesize($img);
if ($width =="") {$j=$height/$height1; $width = $width1 * $j;}
if ($height=="") {$j=$width/$width1; $height = $height1 * $j;}
$new_width = $width;
$new_height = $height;
// Resample
$image_p = imagecreatetruecolor($width, $height);
$image = imagecreatefromjpeg($img);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width1, $height1);
// Output
$img=preg_replace('/h.*\//','',$img);
$img=strtolower($img);
$dest="thumbs/$img";
imagejpeg($image_p,$dest);
}
}
?>

Answer 1

The purpose was to make sure that only images are uploaded, so create_function() or function() are not really needed. In fact, all I really needed was the following code snippet:
Code:
$end=substr($_FILES['pix']['type'], 0, 6);
$end=strtolower($end);
In short, the following code will check to see if the image being uploaded is an image. Not displayed is the code to be sure the user of the script is me. The script will overwrite the image if the same filename already exists and Overwrite was selected. A thumbnail is created and, lastly, a message is displayed saying that the file was successfully uploaded with the size.
Here is the full code:
Code:
<?php
$end=substr($_FILES['pix']['type'], 0, 6);
$end=strtolower($end);
if($end=="image/") {}
else {echo"<script type=\"text/javascript\">
window.location = \"http://www.animeviews.com/images/picform.php\"
</script>";
exit;
}
if(!isset($_POST['Upload']) and !isset($_POST['Overwrite']))
{
include("picform.php");
} # endif
else
{
if($_FILES['pix']['tmp_name'] == "none")
{
echo "<b>File did not successfully upload. Check the
file size. File must be less than 500K.<br>";
include("picform.php");
exit();
}
$destination = $_FILES['pix']['name'];
$destination = strtolower($destination);
$temp_file = $_FILES['pix']['tmp_name'];
if (file_exists($destination) and $_POST['Overwrite']!="Overwrite") {
echo "The file $destination already exists.";exit();
}
#########
move_uploaded_file($temp_file,$destination);
echo "<p><b>The file has successfully uploaded:</b>
{$destination}
({$_FILES['pix']['size']})</p>";
$img="http://www.animeviews.com/images/$destination";
$img = $destination;
$width = "180";
##$height = "";
// Get new dimensions
list($width1, $height1) = getimagesize($img);
if (!isset($width)) {$j=$height/$height1; $width = $width1 * $j;}
if (!isset($height)) {$j=$width/$width1; $height = $height1 * $j;}
$new_width = $width;
$new_height = $height;
// Resample
$image_p = imagecreatetruecolor($width, $height);
$image = imagecreatefromjpeg($img);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width1, $height1);
// Output
$img=preg_replace('/h.*\//','',$img);
$img=strtolower($img);
$dest="thumbs/$img";
imagejpeg($image_p,$dest);
}

Answer 2

i'll try to describe the solution:
Legacy code: create_function('$a', 'return file_has_extension(\'' . $fn . '\', $a);')
Perfect code: function ($a) use ($fn) { return file_has_extension ($fn, $a); }
Explanation: in the first case, you can see the removed function named create_function, which creates a new closure (example of simple closue: function ($args) use ($extraArg - here is extra vars. which you need into the closure, 'use' - construction can be ummitted) { return ...$args }. Closure is equals type callable, you can read this documentation and see, that the first argument of previous function (it's array_map) will be the callable type, all you need pass the same type with the same behavior).
In the second case, you can see some strange construction like this use ($fn), it's necessary, because the closure|callable type has the own variable scope (more here).
More, about Closure and him scope here.
Rewritten file_has_extension function:
function file_has_extension($fn, $ext) {
if (is_array($ext)){
return array_reduce(
array_map(
function ($a) use ($fn) {
return file_has_extension($fn, $a);
},
$ext
),
function ($a, $b) {
return $a || $b;
},
false
);
}
return stripos($fn, '.' . strtolower($ext)) === strlen($fn) - strlen($ext) + 1;
}