Is possible do a remote callback to php file ?

As i know, php is a server side language, that's would like mean if we don't have a direct access (ftp/ssh...) is not possible read the code into php file. If we try to download a php file remotely, we can only see the HTML code.

My question is:

Is possible (if we know the structure, variables contained on a determinated file) do a remotly call for see the variables and the structure what contains ?

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For example, if we have a php file that contain a SQL configuration, is possible do a remotely call for see the configuration ?