package Apache::MVC;
-use base qw(Class::Accessor Class::Data::Inheritable);
-use attributes ();
-use Class::DBI::Loader;
-use UNIVERSAL::require;
-use Apache::Constants ":common";
+use base 'Maypole';
+use Apache;
+use Apache::Request;
use strict;
use warnings;
-our $VERSION = "0.1";
-__PACKAGE__->mk_classdata($_) for qw( _config init_done view_object );
-__PACKAGE__->mk_accessors ( qw( config ar params objects model_class
-args action template ));
-__PACKAGE__->config({});
-__PACKAGE__->init_done(0);
-
-
-sub import {
- my $real = shift;
- if ($real ne "Apache::MVC") {
- no strict 'refs';
- *{$real."::handler"} = sub { Apache::MVC::handler($real, @_) };
- }
-}
-
-# This is really dirty.
-sub config {
- my $self = shift;
- if (ref $self) { return $self->_config_accessor(@_) }
- return $self->_config(@_);
-}
-
-sub set_database {
- my ($calling_class, $dsn) = @_;
- $calling_class = ref $calling_class if ref $calling_class;
- my $config = $calling_class->config;
- $config->{model} ||= "Apache::MVC::Model::CDBI";
- $config->{model}->require;
- $config->{dsn} = $dsn;
- $config->{loader} = Class::DBI::Loader->new(
- namespace => $calling_class,
- dsn => $dsn
- );
- $config->{classes} = [ $config->{loader}->classes ];
- for my $subclass (@{$config->{classes}}) {
- no strict 'refs';
- unshift @{$subclass."::ISA"}, $config->{model};
- $config->{model}->adopt($subclass)
- if $config->{model}->can("adopt");
- }
-}
-
-sub init {
- my $class = shift;
- my $config = $class->config;
- $config->{view} ||= "Apache::MVC::View::TT";
- $config->{view}->require;
- $config->{display_tables} ||= [ $class->config->{loader}->tables ];
- $class->view_object($class->config->{view}->new);
- $class->init_done(1);
-
-}
-
-sub class_of {
- my ($self, $table) = @_;
- return $self->config->{loader}->_table2class($table);
-}
-
-sub handler {
- # See Apache::MVC::Workflow before trying to understand this.
- my $class = shift;
- $class->init unless $class->init_done;
- my $r = bless { config => $class->config }, $class;
- $r->get_request();
- $r->parse_location();
-
- $r->model_class($r->class_of($r->{table}));
- my $status = $r->is_applicable;
- if ($status == OK) {
- $status = $r->call_authenticate;
- return $status unless $status == OK;
- $r->additional_data();
-
- $r->model_class->process($r);
- } else {
- # Otherwise, it's just a plain template.
- delete $r->{model_class};
- $r->{path} =~ s{/}{}; # De-absolutify
- $r->template($r->{path});
- }
- return $r->view_object->process($r);
-}
+our $VERSION = "0.3";
sub get_request {
- my $self = shift;
- require Apache; require Apache::Request;
- $self->{ar} = Apache::Request->new(Apache->request);
+ shift->{ar} = Apache::Request->new(Apache->request);
}
sub parse_location {
$self->{path} = $self->{ar}->uri;
my $loc = $self->{ar}->location;
$self->{path} =~ s/^$loc//; # I shouldn't need to do this?
+ $self->{path} ||= "frontpage";
my @pi = split /\//, $self->{path};
shift @pi while @pi and !$pi[0];
$self->{table} = shift @pi;
$self->{args} = \@pi;
$self->{params} = { $self->{ar}->content };
+ $self->{query} = { $self->{ar}->args };
}
-sub is_applicable {
- my $self = shift;
- my $config = $self->config;
- $config->{ok_tables} = {map {$_ => 1} @{$config->{display_tables}}};
- warn "We don't have that table ($self->{table})"
- unless $config->{ok_tables}{$self->{table}};
- return DECLINED() unless exists $config->{ok_tables}{$self->{table}};
-
- # Does the action method exist?
- my $cv = $self->model_class->can($self->{action});
- warn "We don't have that action ($self->{action})" unless $cv;
- return DECLINED() unless $cv;
-
- # Is it exported?
- $self->{method_attribs} = join " ", attributes::get($cv);
- do { warn "$self->{action} not exported";
- return DECLINED()
- } unless $self->{method_attribs} =~ /\bExported\b/i;
- return OK();
-}
-
-sub call_authenticate {
- my $self = shift;
- return $self->model_class->authenticate($self) if
- $self->model_class->can("authenticate");
- return $self->authenticate();
-}
-
-sub additional_data {}
-
-sub authenticate { return OK }
-
1;
=head1 NAME
-Apache::MVC - Web front end to a data source
+Apache::MVC - Apache front-end to Maypole
=head1 SYNOPSIS
package BeerDB;
use base 'Apache::MVC';
- sub handler { Apache::MVC::handler("BeerDB", @_) }
- BeerDB->set_database("dbi:mysql:beerdb");
+ BeerDB->setup("dbi:mysql:beerdb");
BeerDB->config->{uri_base} = "http://your.site/";
BeerDB->config->{display_tables} = [qw[beer brewery pub style]];
# Now set up your database:
=head1 DESCRIPTION
-A large number of web programming tasks follow the same sort of pattern:
-we have some data in a datasource, typically a relational database. We
-have a bunch of templates provided by web designers. We have a number of
-things we want to be able to do with the database - create, add, edit,
-delete records, view records, run searches, and so on. We have a web
-server which provides input from the user about what to do. Something in
-the middle takes the input, grabs the relevant rows from the database,
-performs the action, constructs a page, and spits it out.
-
-This module aims to be the most generic and extensible "something in the
-middle".
-
-An example would help explain this best. You need to add a product
-catalogue to a company's web site. Users need to list the products in
-various categories, view a page on each product with its photo and
-pricing information and so on, and there needs to be a back-end where
-sales staff can add new lines, change prices, and delete out of date
-records. So, you set up the database, provide some default templates
-for the designers to customize, and then write an Apache handler like
-this:
-
- package ProductDatabase;
- use base 'Apache::MVC';
- __PACKAGE__->set_database("dbi:mysql:products");
- BeerDB->config->{uri_base} = "http://your.site/catalogue/";
- ProductDatabase::Product->has_a("category" => ProductDatabase::Category);
- # ...
-
- sub authenticate {
- my ($self, $request) = @_;
- return OK if $request->{ar}->get_remote_host() eq "sales.yourcorp.com";
- return OK if $request->{action} =~ /^(view|list)$/;
- return DECLINED;
- }
- 1;
+Maypole is a Perl web application framework to Java's struts. It is
+essentially completely abstracted, and so doesn't know anything about
+how to talk to the outside world. C<Apache::MVC> is a mod_perl based
+subclass of Maypole.
-You then put the following in your Apache config:
+To use it, you need to create a package which represents your entire
+application. In our example above, this is the C<BeerDB> package.
- <Location /catalogue>
- SetHandler perl-script
- PerlHandler ProductDatabase
- </Location>
+This needs to first inherit from C<Apache::MVC>, and then call setup.
+This will give your package an Apache-compatible C<handler> subroutine,
+and then pass any parameters onto the C<setup_database> method of the
+model class. The default model class for Maypole uses L<Class::DBI> to
+map a database to classes, but this can be changed by messing with the
+configuration. (B<Before> calling setup.)
-And copy the templates found in F<templates/factory> into the
-F<catalogue/factory> directory off the web root. When the designers get
-back to you with custom templates, they are to go in
-F<catalogue/custom>. If you need to do override templates on a
-database-table-by-table basis, put the new template in
-F<catalogue/I<table>>.
+Next, you should configure your application through the C<config>
+method. Configuration parameters at present are:
-This will automatically give you C<add>, C<edit>, C<list>, C<view> and
-C<delete> commands; for instance, a product list, go to
+=over
- http://your.site/catalogue/product/list
+=item uri_base
-For a full example, see the included "beer database" application.
+You B<must> specify this; it is the base URI of the application, which
+will be used to construct links.
+
+=item display_tables
-=head1 HOW IT WORKS
+If you do not want all of the tables in the database to be accessible,
+then set this to a list of only the ones you want to display
-There's some documentation for the workflow in L<Apache::MVC::Workflow>,
-but the basic idea is that a URL part like C<product/list> gets
-translated into a call to C<ProductDatabase::Product-E<gt>list>. This
-propagates the request with a set of objects from the database, and then
-calls the C<list> template; first, a C<product/list> template if it
-exists, then the C<custom/list> and finally C<factory/list>.
+=item rows_per_page
-If there's another action you want the system to do, you need to either
-subclass the model class, and configure your class slightly differently:
+List output is paged if you set this to a positive number of rows.
- package ProductDatabase::Model;
- use base 'Apache::MVC::Model::CDBI';
+=back
- sub supersearch :Exported {
- my ($self, $request) = @_;
- # Do stuff, get a bunch of objects back
- $r->objects(\@objects);
- $r->template("template_name");
- }
+You should also set up relationships between your classes, such that,
+for instance, calling C<brewery> on a C<BeerDB::Beer> object returns an
+object representing its associated brewery.
- ProductDatabase->config->{model_class} = "ProductDatabase::Model";
+For a full example, see the included "beer database" application.
+
+=head1 INSTALLATION
+
+Create a driver module like the one above.
+
+Put the following in your Apache config:
+
+ <Location /beer>
+ SetHandler perl-script
+ PerlHandler BeerDB
+ </Location>
-(The C<:Exported> attribute means that the method can be called via the
-URL C</I<table>/supersearch/...>.)
+Copy the templates found in F<templates/factory> into the
+F<beer/factory> directory off the web root. When the designers get
+back to you with custom templates, they are to go in
+F<beer/custom>. If you need to do override templates on a
+database-table-by-table basis, put the new template in
+F<beer/I<table>>.
-Alternatively, you can put the method directly into the specific model
-class for the table:
+This will automatically give you C<add>, C<edit>, C<list>, C<view> and
+C<delete> commands; for instance, a list of breweries, go to
- sub ProductDatabase::Product::supersearch :Exported { ... }
+ http://your.site/beer/brewery/list
-By default, the view class uses Template Toolkit as the template
-processor, and the model class uses C<Class::DBI>; it may help you to be
-familiar with these modules before going much further with this,
-although I expect there to be other subclasses for other templating
-systems and database abstraction layers as time goes on. The article at
-C<http://www.perl.com/pub/a/2003/07/15/nocode.html> is a great
-introduction to the process we're trying to automate.
+For more information about how the system works and how to extend it,
+see L<Maypole>.
=head1 AUTHOR