phroute VS dispatch

The router code for this could look like (using Phroute for the example). The functions could be sent to classes if you have that setup.

Finally, add a router to map all of this out. You could use a library, some one noted FastRoute, there a few out there like Phroute for one.

How hard did you look? There are plenty out there. FastRoute, Phroute, based on FastRoute, with basic middleware, League/Route - routing with middleware, using FastRoute, PSR 7 & 15, Slim Framework, at it's core, it like League/Route, etc. None of these require a full framework to use.

Using a router library like FastRoute or Phroute to show the example

Someone mentioned FastRoute. You can look at Phroute as well - https://github.com/mrjgreen/phroute

Additionally, you lose the checks at the top of those files (here' and here if you implement middleware. Here is one example using pretty URLs and a router library. Using Phroute to show the example - pseudo code to illustrate:

Using Phroute to show the example

This can be refactored. If you use start using a router and middleware, this can be done as middleware (or a before/after filter for older libraries - See the Filter Group section on this library for example usage - https://github.com/mrjgreen/phroute)

Dispatch - https://github.com/noodlehaus/dispatch

If OOP too much at this time, here is a procedural framework like Slim - https://github.com/noodlehaus/dispatch

Why though? If your customer is used to procedural code, you could still use classes, if you choose, in the base framework. Or is this an issue with keeping up with PHP 4 support per the readme? You've tested your "framework" with 5.3, so stick with 5.3 (go higher, please) and cut off PHP 4 support. Then, at least you can use Slim v2 to start. Still want procedural - here is noodlehaus/dispatch as a base.

You can also use this for a simpler API to help you get started- https://github.com/noodlehaus/dispatch