How get variables declared on include page only (not the containing page)?

Question

I know that I can use get_defined_vars() to get the variables declared on a page, but I only want the variables declared on the include page.

I know I can do this:

//Get variables of containing page only
$mainPage = get_defined_vars();

//Include new page
include "somepage.php";

//Get variables combined for include and my page
$sothPages = get_defined_vars();

//Find out keys included page
$includeKeys = array_diff_key( $bothPages, $mainPage );

//Now loop through and use only those keys
....

But that seems a little messy and slow (especially if I include multiple pages and have to redo this for each one - the $mainPage array will keep growing). Is there a better way?

NOTE: The pages are included dynamically from a list in a properties file, so the code won't know ahead of time which to include

Answer 1

Assuming you don't have a variable named $_filename in the file:

function getVarsFromPHPFile($_filename) {
    include $_filename;
    unset($_filename);
    return get_defined_vars();
}

$includeKeys = getVarsFromPHPFile('somepage.php');

This should work provided that you aren't declaring the variables as global.

Of course, if you change somepage.php to return an array (as in return array(...);), you could just do $includeKeys = include 'somepage.php'; instead.