/ 
SweetPea-2.3664
/ SweetPea::Documentation::HowItWorks

NAME

SweetPea::Documentation::HowItWorks

DESCRIPTION

This documentation explains how SweetPea processes requests from the browser, how and why the application file system structure and hierarchy works, and some configuration options.

SYNOPSIS

This documentation assumes that you are, have or intend to use the SweetPea application generator via SweetPea::Cli to produce your web application. The following documentation uses the generated files and structure in its examples.

FILES AND HIERARCHY

/extras                 ## project files, makefiles, etc
/static                 ## static content (html, css, js)
/sweet                  ## application files are stored here
    /application        ## MVC files are stored here
        /Controller     ## controllers are stored here
            Root.pm     ## index controller (should always exist)
            Sweet.pm    ## new application welcome page controller
        /Model          ## models are stored here
            Schema.pm   ## new application boiler-plate model 
        /View           ## views are stored here
            Main.pm     ## new application boiler-plate view
    /sessions           ## local session files are stored here
    /templates          ## templates and layouts are stored here
    App.pm              ## plugins (other modules, etc) loaded here
/.htaccess              ## pretty-urls and security on apache
/.pl                    ## dispatcher (controller/action router)
/.server                ## development http server
/routes.pl              ## user-defined routes

HOW IT WORKS

SweetPea uses a simple MVC ideology for processing and responding to requests. Here is an example request and response outlining how SweetPea behaves when a request is recieved.

## Step-By-Step

1. The user requests the url http://localhost/admin/auth/

    #  Note! this works on sub-directories (where the web root is not the
    #  current working directory) as well as root

2. .pl (the dispatcher) extracts the request path and matches it against
the routes table.

    #  admin/auth either matches as a Controller or Controller/Action.
    #  e.g. Controller::Admin::auth() or Controller::Admin::Auth::_index()

3. sweet->run(); loads all plugins and executes the application

    #  .pl (dispatcher/router) invokes sweet->run,
    #  the run method executes the global or local _begin method,
    #  then executes the action or global or local _index method, and
    #  finally executes the global or local _end method.
    #  the start and finish methods are then called to create, render
    #  and finalize the response and output.

FILES AND HIERARCHY

sweet/application/Controller/Root.pm

Controller::Root

The Root.pm controller is the default controller similar in function to
a directory index (e.g. index.html). When a request is received that can
not be matched in the routing table, the root/index
(or Controller::Root::_index) method is invoked. This makes the _index
method of Controller::Root, a kind of global fail-safe or fall back
method.

The _begin method is executed before the requested action, if no action
is specified in the request the _index method is used, The _end method
is invoked after the requested action or _index method has been
executed.

The _begin, _index, and _end methods can exist in any controller and
serves the same purposes described here. During application request
processing, these special routines are checked for in the namespace of
the current requested action's Controller, if they are not found then
the (global) alternative found in the Controller::Root namespace will
be used.

The _startup method is a special global method that cannot be overridden
and is executed first with each request. The _shutdown is executed last
and cannot be overridden either.

# in Controller/Root.pm
package Controller::Root;
sub _startup { my ( $self, $s ) = @_; }
sub _begin { my ( $self, $s ) = @_; }
sub _index { my ( $self, $s ) = @_; }
sub _end { my ( $self, $s ) = @_; }
sub _shutdown { my ( $self, $s ) = @_; }
1;

sweet/application/Controller/Sweet.pm

Controller::Sweet

# Sweet.pm
* A welcome page for the newly created application. (Safe to delete)

sweet/application/Model/Schema.pm

Model::Schema

# Model/Schema.pm
The Model::Schema boiler-plate model package is were your data
connection, accessors, etc can be placed. SweetPea does not impose
a specific configuration style, please feel free to connect to your
data in the best possible fashion. Here is an example of how one
might use this empty package with DBIx::Class.

# in Model/Schema.pm
package Model::Schema;
use base qw/DBIx::Class::Schema::Loader/;
__PACKAGE__->loader_options(debug=>1);
1;

# in App.pm
use Model::Schema;
sub plugins {
    ...
    $s->plug('data', sub { shift; return Model::Schema->new(@_) });
}

# example usage in Controller/Root.pm
sub _index {
    my ($self, $s) = @_;
    ...
    $s->data->connect($dbi_dsn, $user, $pass, \%dbi_params);
    ...
}

sweet/application/View/Main.pm

View::Main

# View/Main.pm
The View::Main boiler-plate view package is were your layout/template
accessors and producers might be stored. Each view is in fact a package
that determines how data should be rendered back to the user in
response to the request. Examples of different views are as follows:

View::Main - Main view module that renders layouts and templates
based on the main application's user interface design.

View::Email::HTML - A view module which renders templates to
be emailed as HTML.

View::Email::TEXT - A view module which renders templates to be
emailed as plain text.

Here is an example of how one might use this empty
package with Template (template toolkit).

# in View/Main.pm
package View::Main;
use base Template;
sub new {
    return __PACKAGE__->new({
    INCLUDE_PATH => 'sweet/templates/',
    EVAL_PERL    => 1,
    });
}
1;

# in App.pm
use View::Main;
sub plugins {
    ...
    $s->plug('view', sub{ shift; return View::Main->new(@_) });
}

# example usage in Controller/Root.pm
sub _index {
    my ($self, $s) = @_;
    $s->view->process($template, { s => $s });
}

sweet/application/App.pm

App

# App.pm
The App application package is the developers access point to
configure and extend the application before request processing. This
is typically done using the plugins method. This package contains
the special and required plugins method. Inside the plugins method is
were other Modules are loaded and Module accessors are created using
the core "plug" method. The following is an example of App.pm usage.

package App;
use warnings;
use strict;
use HTML::FormFu;
use HTML::GridFu;
use Model::Schema;
use View::Main;

sub plugins {
    my ( $class, $s ) = @_;
    my $self = bless {}, $class;
    $s->plug( 'form', sub { shift; return HTML::FormFu->new(@_) } );
    $s->plug( 'data', sub { shift; return Model::Schema->new(@_) } );
    $s->plug( 'view', sub { shift; return View::Main->new(@_) } );
    $s->plug( 'grid', sub { shift; return HTML::GridFu->new(@_) } );
    return $s;
}
1;    # End of App

.htaccess

htaccess

# .htaccess
The .htaccess file allows apache-type web servers that support
mod-rewrite to automatically configure your application environment.
Using mod-rewrite your application can make use of pretty-urls. The
requirements for using .htaccess files with your SweetPea application
are as follows:

mod-rewrite support
.htaccess support with Allow, Deny (in most cases)

# in .htaccess
DirectoryIndex .pl
AddHandler cgi-script .pl .pm .cgi
Options +ExecCGI +FollowSymLinks -Indexes

RewriteEngine On
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteRule (.*) .pl/$1 [L]

.pl

pl

# .pl
The .pl file is the main application router/dispatcher. It is
responsible for executing all pre and post processing routines as well
as directing requests to the appropriate controllers and actions.

#!/usr/bin/env perl

use SweetPea;
sweet->run;

.server

server

# .server
The .server script is a development http server which can be used to
quickly, test, build and deploy your SweetPea web application.

perl .server
# or, auto-reload code files per request
perl .server 80 update

routes.pl

routes

# routes.pl
The routes.pl file is where one might place custom url -to- code
(or controllers and actions) mappings.

my $r = {
    '/path' => sub {
        my $s = shift;
        # $s->forward('SomeController/and_action'); or
        # SomeController->new->and_action(); or
        # simply add your action here!
    }
}

SPECIAL CONTROLLER ROUTINES

_startup

# _startup
sub _startup {...}
The _startup method is a special global method that cannot be overridden
and is executed before any other methods automatically with each request.

_begin

# _begin
sub _begin {...}

The begin method can exist both globally and locally, and will be
automatically invoked per request. When a request is processed,
SweetPea checks whether the _begin method exists in the namespace
of the Controller being requested, if not it checks whether the
_begin method exists in the Controller::Root namespace and
executes that method. If you opt to keep and use the default
controller Controller::Root, then its _begin method will be
defined as the global _begin method and will be executed
automatically with each request. The automatic execution of
_begin in Controller::Root can be overridden by adding a _begin
method to the namespace of the controller to be requested.

This special method is useful for checking user permissions, etc.

_index

# _index
sub _index {...}

The index method can exist both globally and locally, and will
be automatically invoked *only* if an action is not specified.
When a request is processed, SweetPea scans the controllers
folder building a table of controllers and actions for
dispatching. The dispatching routine executes attempts to
execute the action, if no action is specified, it
default to executing the global or local _index method
looking locally first, then globally ofcourse. The automatic
execution of _index in Controller::Root can be overridden by
adding a _index method to the namespace of the controller to
be requested.

This special method acts as a directory index or index.html
file in that it is executed when no other file (action) is
specified.

_end

# _end
sub _end {...}

The end method can exist both globally and locally, and will be
automatically invoked per request. When a request is processed,
SweetPea checks whether the _end method exists in the namespace
of the Controller being requested, if not it checks whether the
_end method exists in the Controller::Root namespace and
executes that method. If you opt to keep and use the default
controller Controller::Root, then its _end method will be
defined as the global _end method and will be executed
automatically with each request. The automatic execution of
_end in Controller::Root can be overridden by adding a _end
method to the namespace of the controller to be requested.

This special method is useful for performing cleanup
functions at the end of a request.

_shutdown

# _shutdown
sub _shutdown {...}
The _shutdown method is a special global method that cannot be overridden
and is executed after all other methods automatically with each request.

CONTROLLER RULES AND SYNTAX

The anatomy of a controller method

Controllers are used by SweetPea in an OO (object-oriented)
fashion and thus, all controller methods should follow the
same design as they are passed the same parameters.

package Controller::Foo;

sub bar {
    my ($self, $s) = @_;
    ...
}

1;

The foo method above (as well as al other controller methods)
are passed at least two objects, an instance of the current
controller usually referred to as $self, and an instance of
the SweetPea application object usually referred to as $s.

Note! Actions prefixed with an underscore can not be
displatched to using URLs.

How to use plugins (other modules)

Plugins are a great way to extend the functionality of a
SweetPea application. Plugins are defined in the application
package App.pm inside of the special plugins method as
follows:

# inside of App.pm
package App;
...
use CPAN::Module;

sub plugins {
    ...
    $s->plug( 'cpan', sub { shift; return CPAN::Module->new(@_) } );
    return $s;
}
...

# notice below how an accessor is created for the ficticious
CPAN::Module in the SweetPea namespace

# inside sweet/Controller/MyController.pm
sub _index {
    my ($self, $s) = @_;
    $s->cpan->some_method(...);
}

# when $s->cpan is called, it creates (unless the object reference
exists) and returns a reference to that module object. To create
or initialize another object, simply call the unplu method on the
object's name.

# inside sweet/Controller/MyController.pm
sub _index {
    my ($self, $s) = @_;
    my $foo = $s->cpan;
    my $bar = $s->cpan;
    my $baz = $s->unplug('cpan')->cpan;
}

# in the example above, $foo and $bar hold the same reference, but
$baz is holding a new refernce as if it called CPAN::Module->new;

INSTANTIATION

new

The new method initializes a new SweetPea object.

# in your .pl or other index/router file
my $s = SweetPea->new;

run

The run method discovers
controllers and actions and executes internal pre and post request processing
routines.

# in your .pl or other index/router file
my $s = SweetPea->new->run; # start processing the request

NOTE! CGI, CGI::Cookie, and CGI::Session are plugged in automatically
by the run method.

# accessible via $s->cgi, $s->cookie, and $s->session

ROUTING/DISPATCHING

The routes method like most popular routing mechanisms allows you to map
urls to routines. SweetPea by default uses an auto-discovery mechanism on
the controllers folder to create routes automatically, however there are
times when additional flexibility is required.

There are two types of routes defined when your application is executed,
auto-routing and manual routing. As stated before, auto-routing
automatically builds routes base on the Controllers in your applications
controllers folder (which is created automatically when you "make" an app
using the sweetpea cli). Manual routing is usually established in the
dispatcher file as follows:

sweet->routes({
    
    '/' => sub {
        shift->html('Index page much!');
    }
    
})->new;

SweetPea routing has support for inline URL parameters and wildcard
operators. See examples below:

sweet->routes({
    
    '/:goto' => sub {
        my $s = shift;
        $s->html('Your trying to get to ' . $s->param('goto') );
        ...
    },
    '/download/*' => sub {
        my $s = shift;
        $s->redirect($s->param('*')) if $s->param('*');
        ...
    },
    '/dl/:file/:from' => sub {
        my $s = shift;
        if ($s->param('file')) {
            my $contents = $s->file('<',
                $s->param('from') . '/' . $s->param('file');
            );
        }
        ...
    }
    
})->run;

CONTROLLERS AND ACTIONS

Controllers are always created in the sweet/controller folder and defined
under the Controller namespace, e.g. Controller::MyController. In keeping
with simplicity, controllers and actions are actually packages and
routines ( controller/action = package controller; sub action {...} ).

NOTE! Actions prefixed with an underscore e.g. _foo can not be dispatched to
using URLs but are listed in the dispatch table and are available to
the forward, detach and many other methods that might invoke an
action/method.

OTHER DOCUMENTATION

PROJECT

SweetPea - A web framework that doesn't get in the way, or suck.

PROJECT DESCRIPTION

SweetPea is a modern web application framework that is fast, scalable, and light-weight. SweetPea has a short learning curve and a common sense object-oriented API. See SweetPea::Cli::Documentation for a QuickStart Guide.

PROJECT POD URL

http://app.alnewkirk.com/pod/projects/sweetpea/

AUTHOR

Al Newkirk, <al.newkirk at awnstudio.com>

BUGS

Please report any bugs or feature requests to bug-SweetPea at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=SweetPea. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc SweetPea

You can also look for information at:

ACKNOWLEDGEMENTS

Al Newkirk <al.newkirk@awnstudio.com>

COPYRIGHT & LICENSE

Copyright 2009 Al Newkirk, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.