PHP file security on webserver

Question

I'm slowly learning PHP, MySQL, along with some HTML, using localhost as my webserver. However, I'm starting to wonder how my .php files are going to be secured if I put this actually on the Internet.

I have a webpage at localhost/app.php that includes a form, some PHP code, and some MySQL queries. The MySQL credential information is located one directory above where app.php is located, but how do I prevent from strangers accessing the contents of app.php, including MySQL data structure, commands I'm using, etc. When you view the source code in a browser, you only see the HTML part of it, but couldn't someone download app.php and look into the actual file if he wanted to?

What's the proper way of constructing the file structure? Links or comments are greatly appreciated! TIA!

Answer 1

Well, if you're using the .php extension, then Apache will serve up the parsed version -- echo and print will output but your variables won't.

If you're still concerned there's a few ways of making your files more secure.

• Apache aliasing is common -- it lets you have one directory act like it's another. In this case, you'd alias your PHP directory to some directory on your domain. If your file structure is /home/user/my_files/, you might alias my_files to be www.my-domain.com/files. The script would not be accessible there to the requests, but it would be accessible to something on the server.
• Symbolic links or symlinks can accomplish the same as the above.
• simply place the config files somewhere else and directly reference them. Generally not a good idea as it is hard-coding file locations, but it is an option.
• the CodeIgniter method: in your index.php have define( 'IN_APPLICATION', 1 ); in your config files have if( !defined( 'IN_APPLICATION' ) ) die( 'No direct script access allowed' );