Request another PHP file with any Method (NOT cURL!) - php

Question

I am building an API in PHP and want the user to include some plug-ins written in any language of choice in a designated directory. The way this should work is that the API sends a request to that user's plug-in file and returns the result.
This should be accomplished without cURL, because cURL is unavailable in this particular environment, so answers using cURL won't be helpful.
The issue that I am having is that my function literally reads the contents of the file (without executing it) when the plug-in is also written in PHP.
This is my code:
function sendRequest($url, $method, $body){
$http = array(
'method' => $method,
'header' => 'Authorization: sometoken' . "\r\n".
'Content-Type: application/json' . "\r\n",
'content' => $body
);
$context = stream_context_create(array('http' => $http));
if($file = file_get_contents($url, false, $context)){
return $file;
}
else{
return 'Error';
}
}
This is an example of a simple plug-in file written in PHP:
<?php
$input = file_get_contents('php://input');
$input = json_decode($input, true);
echo($input['a'] + $input['b']);
?>
When it is requested from the API it should return the value of a + b. The above code could also be implemented in any other language, it should work either way. These files are stored locally, not on a remote server (where it would work flawlessly).
Is there any way force the file to be executed without cURL? I imagine include and require are also not an option, since the plug-in file should be in a language of choice, not necessarily PHP.
Thanks in advance!

Answer 1

You'll want to look at the PHP command exec
This would allow you do to something like:
exec('php plugin.php param1', $output);
Then read the results back via the $output variable.
Similar things could be done with other applications/scripts (provided they process with absolutely no interaction).