--- 
canonical: 'https://mwop.net/blog/18-More-CGIApp-research...-Try-the-manual%21.html'
title: 'More CGI::App research... Try the manual!'
author: "[Matthew Weier O'Phinney](https://mwop.net)"
created: '2004-01-23T23:02:30-06:00'
updated: '2004-09-20T13:27:44-05:00'
tags:
  - perl
  - personal
  - programming

---
So, I'm a bit of an idiot… it's been so long since I looked at `CGI::App`, and
yet I felt I had such a grasp on it, that I overlooked the obvious step: look
at the [manual!](http://search.cpan.org/%7Ejerlbaum/CGI-Application-3.1/Application.pm)

In particular, there's a whole series of methods that are used to tailor
`CGI:App` to your particular needs, and these include `cgiapp_init()`,
`cgiapp_prerun()`, and `cgiapp_postrun()`.

- **cgiapp_init()** is used to perform application specific initialization
  behaviour, and is called immediately before the `setup()` method. It can be
  used to load settings from elsewhere; if it were called only from a
  superclass from which other modules inherited, it would then provide common
  settings for all modules.
- **cgiapp_prerun()** is called immediately before the selected run-mode. If it
  were called only by your superclass, you could perform items such as
  authorization or even form validation; this would then be standard for all
  your applications. (You can use the `$self->prerun_mode('mode')` call to to
  override the selected run-mode, for instance, thus allowing you to redirect
  to a different mode if a user isn't permitted there.)
- **cgiapp_postrun()** is called after the run-mode has returned its output,
  but before http headers have been generated or anything sent to the web
  browser. Again, if defined in a superclass, it means that you could then
  place the run-mode output *in a specific place within a larger template*, and
  even call other routines to fill in other parts of the main template. You
  could even check to see if certain parameters were passed to the page, and
  change the type of output you send back (XML, PDF, image, etc.), allowing you
  to have a common query element that changes the output type (e.g., a 'print'
  parameter that returns a PDF or a stripped down template).

In addition, you could specify in the superclass that you're using
`CGI::Simple` for the query object (using the `cgiapp_get_query` method), or
you could rewrite the `load_tmpl()` method to use `Template::Toolkit` or some
other templating system, etc.

Doesn't look so crazy anymore…