I've been wanting to redevelop my home website for some time using CGI::Application. The last time I rewrote it from PHP to perl, I developed something that was basically a subset of the things CGI::App does, and those things weren't done nearly as well.

The problem I've been running into has to do with having sidebar content, and wanting to run basically a variety of applications. I want to have a WikiWikiWeb, a photo gallery, some mail forms, and an article database/blog; CGI::App-based modules for each of these all exist. But I want them all to utilize the same sidebar content, as well — and that sidebar content may vary based on the user.

My interest got sparked by this node on Perl Monks. The author tells of an acquaintance who goes by the rule that a CGI::App should have 10-12 states at most; more than that, and you need to either break it apart or rethink your design. And all CGI::Apps inherit from a common superclass, so that they share the same DB connections, templates, etc.

So, I've been investigating this problem. One node on PM notes that his ISP uses CGI::App with hundreds of run modes spread across many applications; they created a module for session management and access control that calls use base CGI::Application; each aplication then calls use base Control, and they all automatically have that same session management and access, as well as CGI::Application.

Another node mentions the same thing, but gives a little more detail. That author writes a module per application, each inheriting from a super class: UserManager.pm, Survey.pm, RSS.pm, Search.pm, etc. You create an API for that super class, and each CGI::App utilizes that API to do its work.

This also seems to be the idea behind CheesePizza, a CGI::App-based framework for building applications. (All pizzas start out as cheese pizzas; you simply add ingredients.) The problem with that, though, is that I have to learn another framework on top of CGI::App, instead of intuiting my own.

But how do I write the superclass? Going back to the original node that sparked my interest, I found a later reply that described how you do this. The big key is that you override the print method — this allows you to customize the output, and from here you could call functions that create your sidebar blocks, and output the content of the CGI::App you just called in a main content area of your template.

Grist for the mill…