NAME CGI::Panel - Create sophisticated event-driven web applications from simple panel objects SYNOPSIS A very simple application... --------------- in simpleapp.cgi: use SimpleApp; my $simple_app = obtain SimpleApp; $simple_app->cycle(); --------------- in SimpleApp.pm: package SimpleApp; use strict; use warnings; use Basket; use base qw(CGI::Panel::MainPanel); sub init { my ($self) = @_; $self->add_panel('basket', new Basket); # Add a sub-panel $self->{count} = 1; # Initialise some persistent data } sub _event_add { # Respond to the button click event below my ($self, $event) = @_; $self->{count}++; # Change the persistent data } sub display { my ($self) = @_; return 'This is a very simple app.

' . # Display the persistent data... "My current count is $self->{count}

" . # Display the sub-panel... $self->panel('basket')->display . '

' . # Display a button that will generate an event... $self->event_button(label => 'Add 1', name => 'add'); } 1; --------------- in Basket.pm: package Basket; use base qw(CGI::Panel); sub display { 'I have the potential to be a shopping basket one day' } 1; --------------- DESCRIPTION CGI::Panel allows applications to be built out of simple object-based components. It'll handle the state of your data and objects so you can write a web application just like a desktop app. You can forget about the http requests and responses, whether we're getting or posting, and all that stuff because that is all handled for you leaving to you interact with a simple API. An application is constructed from a set of 'panels', each of which can contain other panels. The panels are managed behind the scenes as persistent objects. See the sample applications for examples of how complex object-based applications can be built from simple encapsulated components. (To do) USAGE See 'SYNOPSIS' BUGS SUPPORT AUTHOR Robert J. Symes CPAN ID: RSYMES rob@robsymes.com COPYRIGHT Copyright (c) 2002 Robert J. Symes. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module. SEE ALSO perl(1). PUBLIC METHODS Each public function/method is described here. These are how you should interact with this module. new Creates a new panel object Use: my $panel = new Panel; init Initialises a panel object. This should be used to add panels to the current panel. We provide a default method here which can be overridden. Example: sub init { my ($self) = @_; $self->add_panel('first_panel', App::Panel::First); $self->add_panel('second_panel', App::Panel::Second); } parent Get or set the parent of the panel object. Examples: my $parent = $self->parent; $self->parent($other_panel); state This method is provided for convenience. Get or set the state. (Simple accessor for $self->{_state}) Examples: my $state = $self->state; $self->state('STATE1'); get_persistent_id Gets the session id for the application Note: It's essential that all panels are added using the proper add_panel routine. This routine traverses up to the main panel by way of each panel's 'parent' reference. Example: my $id = $self->get_persistent_id; panel Retrieves a panel by name Example: my $first_panel = $self->panel('first_panel'); get_panels Retrieves the set of panels as a hash Example: my %panels = $self->get_panels; add_panel Adds a panel to the current panel in a way that maintains referential integrity, ie the child panel's parent value will be set to the current panel. All panels should be added to their parents using this routine to keep referential integrity and allow certain other mechanisms to work. Example: $self->add_panel('first_panel', new App::Panel::First); remove_panels Remove all the panels from the current panel. Example: $self->remove_panels; local_params Get the parameter list for the current panel. This fetches the parameter list and returns the parameters that are relevant to the current panel. This allows each panel to be written in isolation. Two panels may have input controls (textboxes etc) with the same name and they can each retrieve the value of that input from their %local_params hash. eg my %local_params = $self->local_params my $name = $local_params{name}; event_button Display a button which when pressed re-cycles the application and generates an event to be handled by the next incarnation of the application. The name of the routine that will be called will have _event_ prepended. This is partly for aesthesic reasons but mainly for security, to stop a wily hacker from calling any routine by changing what is passed through the browser. We'll probably be encrypting what is passed through in a later version. Input: label: Caption to display on button name: Name of the event routine: Name of the event routine to call (defaults to name value if not specified) ('_event_' is prepended to the routine name) eg: $shop->event_button(label => 'Add Item', name => 'add', routine => 'add'); event_link Display a link (which can be an image link) which when pressed re-cycles the application and generates an event to be handled by the next incarnation of the application. Input: label: Caption to display on link * OR * img: Image to display as link name: Name of the event routine: Name of the event routine to call (defaults to name value if not specified) ('_event_' is prepended to the routine name) eg: $shop->event_link(label => 'Add Item', name => 'add') CGI input functions The CGI input functions are available here with local_ prepended so the name can be made panel-specific, and they can be called as a method.