ApiStack is a library of PHP classes to help implement API-s, such as JSON-RPC. Actually, JSON-RPC is the only protocol fully supported by now, but the list should be extended.

Stack

Client (external user)
Transport Handles communication with client, forms separate calls as plain strings. E.g. HTTP, socket
Protocol Translates plain string to request object[s] and response object[s] back to plain string. E.g. Json-RPC, SOAP, XML-RPC?
Service Handles request object, prepares arguments, calls requested function.
Functions (your implementation)

Usage

This library provides only base classes for three independent layers -- Transport, Protocol, and Service. You MUST consider how every layer should behave and extend/implement them for your own needs.