I use the term socket for any extension, either unix socket, or internet socket (port).

I check if the socket is all digits
* only integers 0 and larger would pass this test.
I then check if the string is less than or equal to the maximum port number.

By using "if($socket)" I make sure socket isn't false, empty, or the string '0'.

I don't believe I need to initialize $port because $port will always be set if $socket is true. Please show me if I am wrong here. Thanks

This passes anything that is not a valid port (0<int<65535) as a unix socket.
I tested this with unix sockets; this needs to be tested with a non-standard mysql port as well but I don't foresee any issues.

To use a unix socket, even one different than PHP's mysql.default_socket..
* Database Host = localhost:/path/to/socket

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