PHP - open external php file and display in browser - php

Question

I need a php script that will open an external php file (from the same server folder), go through it line by line, and then normally display the page in the browser, as it would by just opening the external php page directly.
I need to open the external file line by line, so I can do some processing on the content of the file before showing it.
My current code is:
<?php
$handle = fopen("test.php", "r");
if ($handle) {
while (($line = fgets($handle)) !== false) {
// process the line here, and change if needed
echo "$line\n";
}
fclose($handle);
}
else {
// error opening the file.
}
?>
This works, and the page is displayed, but any php code in the original external file is not honored - it is written out as text, and not rendered by the browser.
I need the external file to fully display, just as it would if I opened the file (in this case "test.php") by itself.
Other questions I have seen on SO deal with opening or displaying a full file at once, but I need to loop through my file and do some processing on the contents first, so need to evaluate it line by line.
Any ideas would be appreciated.
Thanks

Answer 1

I would save the changes to a temporary file, and then include it.
<?php
$handle = fopen("test.php", "r");
if ($handle) {
while (($line = fgets($handle)) !== false) {
// process the line here, and change if needed
$newCode .= "$line\n";
}
fclose($handle);
}
else {
// error opening the file.
}
// temporary file name
$temp_file = tempnam(sys_get_temp_dir(), 'myfile').".php";
// save modified code
file_put_contents($temp_file, $newCode);
// include modified code
include $temp_file;
// delete file
unlink($temp_file);
?>

Answer 2

Retrieve the content, process it, keep it in memory then eval() it:
<?php
$newCode = "";
$handle = fopen("test.php", "r");
if ($handle) {
while (($line = fgets($handle)) !== false) {
// process the line here, and change if needed
//$line = myLineProcess($line);
$newCode .= "$line\n";
}
fclose($handle);
}
else {
// error opening the file.
}
//run the code
eval('?>'.$newCode.'<?php;');
?>