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CGI::Prototype::Hidden - Create a CGI application by subclassing - hidden field
# in My/App.pm --- package My::App; use base qw(CGI::Prototype::Hidden); # in /some/cgi-bin/program use lib qw(/location); use My::App; My::App->activate;
Dispatching to a particular paged based on the "state" of the application is performed according to param field.
The name of the state is appended to an application-wide package prefix to determine an appropriate class to handle the request.
The package for the class is autoloaded if needed.
The template for the class replaces
.tt(configurable), found in the same
@INCpath, and is therefore likely to be in the same directory.
A "wrapper" template is automatically provided.
Thus, a simple 10-page CGI application will require 23 files: 10 classes, 10 corresponding templates, a wrapper template, a master application class, and a CGI script that loads the master application class and activates it.
The default class is
My::App, but this can be overridden. The default state is
welcome, but this too can be overridden. The default hidden param name for the state is
_state, and if you think this can be overridden, you are correct. See the trend here?
A sample app is the best way to show all of this, of course. We don't have one yet... that's on the TODO list. However, the functions have all been exercised in the tests for this module, including an artificial application, so check that out for at least an example of the interfaces.
These methods or values are the ones you'll most likely change in your application, although you can leave them all alone and it'll still be a valid framework to create your entire application.
The name of the hidden field which will contain the state, defaulting to
In any form you create, or any constructed URL, you must be sure to include this param as part of the form so that the right response can be matched up for the submitted data. For example:
<form> [% self.CGI.hidden(self.config_state_param) %] First name:[% self.CGI.textfield("first_name") %]<br> Last name: [% self.CGI.textfield("last_name") %] <input type=submit> </form>
The class prefix placed ahead of the state name, default
My::App. For example, the controller class for the
welcomestate will be <My::App::welcome>.
You should change this if you are using mod_perl to something that won't conflict with other usages of the same server space. For CGI scripts, the default is an easy classname to remember.
Note that the template also use this name as their prefix, so that your controller and template files end up in the same directory.
The initial page if the state is missing, default
The name of the WRAPPER template, default
If you change
config_class_prefix, you'll want to change this as well so that
WRAPPER.ttends up in the right directory. (I debated doing that for you so you could just say
"WRAPPER.TT", but that'd make more complicated versions of this callback be even more and more complicated.)
The wrapper template is called with
templateset to the wrapped template, which should be processed in the wrapper. The smallest wrapper is therefore:
[% PROCESS $template %]
However, typically, you'll want to define app-wide blocks and variables, and maybe wrap the statement above in an exception catcher. For example:
[%- TRY; content = PROCESS $template; self.CGI.header; self.CGI.start_html; content; self.CGI.end_html; ### exceptions ## for errors: CATCH; CLEAR; self.CGI.header('text/plain'); -%] An error has occurred. Remain calm. Authorities have been notified. Do not leave the general area. [%- FILTER stderr -%] ** [% template.filename %] error: [% error.info %] ** [% END; # FILTER END; # TRY -%]
This sends back a plain message to the browser, as well as logging the precise error text to
STDERR, and hopefully the web error log.
The location of the compiled Perl templates, default
$<is the current user's numeric user ID). You'll want this to be some place that the process can write, but nobody else can. The default is functional, but not immune to other hostile users on the same box, so you'll want to override that for those cases.
The suffix replacing
.pmwhen the module name is mapped to the template name. By default, it's
You will most likely not need to change these, but you'll want to stay away from their names.
Called with a page name, returns a page object. Will also autoload the package.
This is still an experimental feature that will be reworked in future releases.
Called with a page name, returns a new page object that can be used as
selfin a template, mixing in the code from the page's class for additional heavy lifting.
For example, to have a "subpage" plugin, create a
subpage.pmfile, then include the tt with:
[% INCLUDE My/App/subpage.tt self = self.plugin("subpage") other = parms go = here %]
subpage.tt, calls to
self.SomeMethodwill first search the original page's lineage, and then the plugin class lineage for a definition for
Overridden from CGI::Prototype. Selects either the hidden field state, or the default state, and returns the page object.
Returns the simple name for the current page object by stripping off the
config_class_prefix. Note that this will fail in the event of prototype page constructed on the fly, rather than a named class. Hmm, I'll have to think about what that implies.
Overridden from CGI::Prototype. Forces the hidden state param to the shortname of the current object, then calls
If you need page-specific render_enter items, put them here. The default definition does nothing. This is to keep from having to call superclass methods for
Overridden from CGI::Prototype. Calls
respond_per_page, looking for a true value, which is then returned.
If you have site-wide buttons (like a button-bar on the side or top of your form), look for them in
respond_per_app, and return the new page from there. Otherwise, return
undef, and it'll fall through to the per-page response.
A hook for application-wide responses, defaulting to
undef. Should return either a page object (to be rendered) or a false value (selecting the per-page respond).
respond_per_appreturns false, this hook is then evaluated. It should return a page object to be rendered. The default returns the current page object, so you "stay here" for rendering.
Overridden from CGI::Prototype. Returns the name of a template, defined by replacing the double-colons in the classname of the current page with forward slashes, and then appending
.tt(by default, see
@INCis added to the
INCLUDE_PATHfor the engine, this should find the
.ttfile in the same directory as the
Template->new ( POST_CHOMP => 1, INCLUDE_PATH => [@INC], COMPILE_DIR => $self->config_compile_dir, PROCESS => [$self->config_wrapper], )
Please report any bugs or feature requests to email@example.com, or through the web interface at http://rt.cpan.org. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
Randal L. Schwartz, <firstname.lastname@example.org>
Special thanks to Geekcruises.com and an unnamed large university for providing funding for the development of this module.
Copyright (C) 2003, 2004, 2005 by Randal L. Schwartz
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.5 or, at your option, any later version of Perl 5 you may have available.