$_FILES is empty but move_uploaded_file() works - php

Question

I have the next code:
<?php
if(empty($_FILES))
echo 'vacia';
else
echo 'con algo';
var_dump($_FILES);
$tempFile = $_FILES['Filedata']['tmp_name'];
$fileName = $_FILES['Filedata']['name'];
move_uploaded_file($tempFile, "./" . $fileName);
?>
Now, empty($_FILES) is true because shows me the string 'vacia'. Also show me 'array(0) {}' in var_dump().
But move_uploaded_file() still works perfectly. Could someone explain me that?
the error_reporting(E_ALL) say 'Undefined index Filedata' in each line where I use it, but I can understand why move_uploaded_file() still works :/

Answer 1

You should check the return of move_uploaded_files():
$result = move_uploaded_files($tempFile, "./", $fileName);
It will be true on success or false on error. In your case, it should be false. Since the array indices do not exist, PHP will throw an E_NOTICE level error and use an empty string, so you're actually doing this:
move_uploaded_file('', "./", '');
But without E_NOTICE enabled, there will be no visible error message. (see http://php.net/manual/en/function.error-reporting.php)

Answer 2

You might want to check to see if the file exists instead. Just because the name exists doesn't mean the file exists.
if(is_file($_FILES['Filedata']['tmp_name'])){
echo 'vacia';
}else{
echo 'con algo';
exit("File doesn't exist, I can't move it so I'm out!");
}
var_dump($_FILES);
$tempFile = $_FILES['Filedata']['tmp_name'];
$fileName = $_FILES['Filedata']['name'];
move_uploaded_file($tempFile, "./" . $fileName);