As you all may know, all networks on Ning are open, which means that anyone can look at the source code of a particular network or application, which is great by the way because allows people interested in tweaking their own networks to look at how other application developers have implemented a cool feature in order to learn or replicate.
Here is the url to view the source code of a network on ning:
http: / /w ww.ning.com/view-source.html?appUrl=
subdomain
(replace subdomain with the name that goes before .ning.com in the url of the network you want to look at)
So, when developing keep that in mind, specially if you plan to access other webservices that requires authentication with a personal API key or a password, people
can see your PHP... unless you store this sensitive PHP files on a special place:
/xn_private/

The xn_private directory is the place to store this type of source files, everything in it is acessible only by the network owner and not listed on the public view-source pages.
Here is one example of how to access the sensitive information in your application by referencing a file in your xn_private folder, lets assume that you have a file called myKey.php like this on your xn_private folder:
<?php $myKey='foo bar' ?>
Here is how you would access:
<?php$keyFilePath = $_SERVER['DOCUMENT_ROOT'].'/xn_private/my_key.php';if(file_exists($keyFilePath)){
include_once $keyFilePath;
echo "The secret key is:$myKey";
} else {
die('key not found');
}
?>