Can one .PHP file edit another?

Question

So I have a file for constants. I want to let user define them and then edit my .php filr with that global constants (not xml - real PHP file )

With such code for exampl

Answer 1

You can open the file

$lines = file('myConstants.php');

Edit the content and than save it back

$myFile = 'myConstants.php'
$fh = fopen($myFile, 'w') or die("can't open file");
fwrite($fh, 'DATA HERE');
fclose($fh);

Answer 2

if you are designing your own solution you should refrain from using metaprogramming (check wikipedia) for configuration purposes.

php has a built-in ini-file parser you can use. when you've only got key-value pairs that is sufficient.

writing:

<?php
file_put_contents("settings.ini","[auth]
DB_SERVER=".DB_SERVER."
DB_USER=".DB_USER."
DB_PASS=".DB_PASS."
DB_NAME=".DB_NAME."
");
?>

reading:

<?php
$auth = parse_ini_file("settings.ini");
foreach ($auth as $k => $v) {
define($k,$v);
}
?>