What are the best practices for integrating a PHP file with external modules using Server Side Includes (SSI)?

When integrating a PHP file with external modules using Server Side Includes (SSI), it is important to ensure that the PHP code is properly executed within the included file. One way to achieve this is by using the `virtual` SSI directive to include the PHP file. This directive tells the server to process the included file as if it were a separate request, allowing the PHP code to be executed correctly.

<!--#include virtual="/path/to/your/php/file.php" -->