All, I am considering moving to a true 3-tier structure where the web server does not have direct access to the database server - many times a government requirement. I want to keep the PHP front end and use an application server (middle tier) to handle all the DB calls and sessions. I could use Java or something for the middle layer, but I do not really want to. I would like to implement a PHP application server sitting on top of SQL Relay for pooling and DB abstraction to reduce the need to have more expertise necessary for implementation. Interoperability is important, but not 100% necessary.
With all that being said, what do you think is the best method of communication between PHP and the application server. Just to throw it out there, I have thought about SOAP and XML-RPC. I like SOAP better because it can decrease payload a great deal by not having to use the whole struct method and it is more complex. But the XML-RPC functions are written in C and the SOAP are in PHP. PHP 5 has better object orientation and new XML libs so the SOAP functions should run much faster, but still not native. What are your thoughts? - Paul