Executing file via file_get_contents on remote host - php

Question

I have a script and I don't know why and how it works - one reason for that is I found contradicting information about file_get_contents.
I have three (internal) webservers - all set up the same way, running the same software.
I need to count the number of files in one specific folder on each server (in order to get the number of users logged into a certain application).
For the local server my file counting PHP script is called by a simple include and for the two remote servers I use file_get_contents.
In both cases I refer to the same PHP file. That works - I get the correct number of files for the folder on each server.
Sometimes you read file_get_contents returns just the file content but does not execute the file. In my case the file is executed and I get the correct number of files. So, I'm a bit confused here why my scripts actually work.
My scripts were saved on one server. I want to be more flexible and be able to call the scripts from each server. Therefore I created a new virtual directory on a network folder and moved the script files there, the virtual folder has the same set up on each server. I had to change my script slightly to get the same result again. Instead of a return $num I now have echo $num. If I use return I won't get a result, if I use echo the correct number of files is given. I would prefer to receive the result via return - but I don't know why this doesn't work anymore in the new context.
script which shows the number of files:
function getUserNum($basis_url_server, $url_vaw_scripte, $script_number_users)
{
$serverName = strtoupper($_SERVER['SERVER_NAME']);
//local server
if(strpos(strtoupper($basis_url_server),$serverName) !== false)
{
$numUsers = (include($script_number_users));
}
//remote server
else
{
$path = $basis_url_server.$url_vaw_scripte.$script_number_users;
$numUsers = file_get_contents($path);
//include($path);
}
return $numUsers;
}
echo getUserNum($basis_url_server1, $url_vaw_scripte, $script_number_users)."($label_server1)";
echo getUserNum($basis_url_server2, $url_vaw_scripte, $script_number_users)."($label_server2)";
echo getUserNum($basis_url_server3, $url_vaw_scripte, $script_number_users)."($label_server3)";
script for counting the files (refered as $script_number_users above)
<?php
// 'include' only contains $fadSessionRepository = "E:\Repository\Session"
include dirname(__DIR__).'/vaw_settings.php';
$fi = new FilesystemIterator($pfadSessionRepository, FilesystemIterator::SKIP_DOTS);
$number = (iterator_count($fi)-1)/2 ;
//return $number;
echo $number;
?>

Answer 1

file_get_contents() will execute a GET if given a url, and will read a file if given filesystem path. It is like 2 different function from the same call.
You are actually building a primitive REST webservice instead of actually loading the files as you though, the remote files are executed and you get the output that you would see if you manually loaded them from a browser

Answer 2

file_get_contents() will return the raw content of a local file. For remote files it will return what the webserver delivers. If the webserver executes the script in the file it will get the result of that script. If the webserver doesn't execute the script in the file (due to a misconfiguration for example) you will still get the raw content of the remote script.
In your case I'd just remove the include path and just fetch all scripts over http. It reduces the complexity and the overhead of calling one of three scripts via http instead of loading it directly is negligible.