X-Git-Url: https://git.decadent.org.uk/gitweb/?a=blobdiff_plain;f=lib%2FApache%2FMVC.pm;h=5d999be45e93d971dcb6a1586fef27cceb03b9d5;hb=b4c877459674a8da7943533c780f807f3a355906;hp=a68f0ac29bc727a51428d296cfebfb0bafcaae0d;hpb=1b3ec28e5f2b7f6f5f4c8140a98e114912271a53;p=maypole.git

diff --git a/lib/Apache/MVC.pm b/lib/Apache/MVC.pm
index a68f0ac..5d999be 100644
--- a/lib/Apache/MVC.pm
+++ b/lib/Apache/MVC.pm
@@ -1,103 +1,154 @@
 package Apache::MVC;
-use base qw(Class::Accessor Class::Data::Inheritable);
-use attributes ();
-use Class::DBI::Loader;
+use base 'Maypole';
+use Apache;
+use Apache::Request;
 use strict;
 use warnings;
+our $VERSION = "0.3";
 
-__PACKAGE__->mk_classdata(qw( _config init_done view_object ));
-__PACKAGE__->mk_accessors ( qw( config ar params objects model_class args ));
-__PACKAGE__->config({});
-__PACKAGE__->init_done(0);
+sub get_request {
+    shift->{ar} = Apache::Request->new(Apache->request);
+}
 
-# This is really dirty.
-sub config {
+sub parse_location {
     my $self = shift;
-    if (ref $self) { return $self->_config_accessor(@_) }
-    return $self->_config(@_);
-}
+    $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->{action} = shift @pi;
+    $self->{args} = \@pi;
 
-sub set_database {
-    my ($calling_class, $dsn) = @_;
-    $calling_class = ref $calling_class if ref $calling_class;
-    $calling_class->config->{dsn} = $dsn;
-    $calling_class->config->{loader} = Class::DBI::Loader->new(
-        namespace => $calling_class,
-        dsn => $dsn
-    ); 
+    $self->{params} = { $self->{ar}->content };
+    $self->{query}  = { $self->{ar}->args };
 }
 
-sub init {
-    my $class = shift;
-    my $config = $class->config;
-    $config->{model} ||= "Apache::MVC::Model::CDBI";
-    $config->{view}  ||= "Apache::MVC::View::TT";
-    $config->{classes} = [ $class->config->{loader}->classes ];
-    $config->{display_tables} ||= [ $class->config->{loader}->tables ];
-    for my $class (@{$config->{classes}}) {
-        no strict 'refs';
-        push @{$class."::ISA"}, $class->config->{model};
+1;
+
+=head1 NAME
+
+Apache::MVC - Web front end to a data source
+
+=head1 SYNOPSIS
+
+    package BeerDB;
+    use base 'Apache::MVC';
+    sub handler { Apache::MVC::handler("BeerDB", @_) }
+    BeerDB->set_database("dbi:mysql:beerdb");
+    BeerDB->config->{uri_base} = "http://your.site/";
+    BeerDB->config->{display_tables} = [qw[beer brewery pub style]];
+    # Now set up your database:
+    # has-a relationships
+    # untaint columns
+
+    1;
+
+=head1 DESCRIPTION
+
+A large number of web programming tasks follow the same sort of pattern:
+we have some data in a datasource, typically a relational database. We
+have a bunch of templates provided by web designers. We have a number of
+things we want to be able to do with the database - create, add, edit,
+delete records, view records, run searches, and so on. We have a web
+server which provides input from the user about what to do. Something in
+the middle takes the input, grabs the relevant rows from the database,
+performs the action, constructs a page, and spits it out.
+
+This module aims to be the most generic and extensible "something in the
+middle".
+
+An example would help explain this best. You need to add a product
+catalogue to a company's web site. Users need to list the products in
+various categories, view a page on each product with its photo and
+pricing information and so on, and there needs to be a back-end where
+sales staff can add new lines, change prices, and delete out of date
+records. So, you set up the database, provide some default templates
+for the designers to customize, and then write an Apache handler like
+this:
+
+    package ProductDatabase;
+    use base 'Apache::MVC';
+    __PACKAGE__->set_database("dbi:mysql:products");
+    BeerDB->config->{uri_base} = "http://your.site/catalogue/";
+    ProductDatabase::Product->has_a("category" => ProductDatabase::Category); 
+    # ...
+
+    sub authenticate {
+        my ($self, $request) = @_;
+        return OK if $request->{ar}->get_remote_host() eq "sales.yourcorp.com";
+        return OK if $request->{action} =~ /^(view|list)$/;
+        return DECLINED;
     }
-    $class->view_object($class->config->{view}->new);
+    1;
 
-}
+You then put the following in your Apache config:
 
-sub class_of {
-    my ($self, $table) = @_;
-    return $self->config->{loader}->_table2class($table);
-}
+    <Location /catalogue>
+        SetHandler perl-script
+        PerlHandler ProductDatabase
+    </Location>
 
-sub handler {
-    # See Apache::MVC::Workflow before trying to understand this.
-    my $class = (caller(0))[0];
-    $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;
-    return $status unless $status == 200;
-    $status = $r->call_authenticate;
-    return $status unless $status == 200;
-    $r->find_objects();
-    $r->additional_data();
-    $r->class->process($r);
-}
+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>>. 
 
-sub get_request {
-    my $self = shift;
-    require Apache; require Apache::Request; 
-    $self->{ar} = Apache::Request->new(Apache->request);
-}
+This will automatically give you C<add>, C<edit>, C<list>, C<view> and
+C<delete> commands; for instance, a product list, go to 
 
-sub parse_location {
-    my $self = shift;
-    my @pi = split /\//, $self->{ar}->uri();
-    shift @pi while @pi and !$pi[0];
-    $self->{table} = shift @pi;
-    $self->{action} = shift @pi;
-    $self->{args} = \@pi;
-}
+    http://your.site/catalogue/product/list
 
-sub is_applicable {
-    my $self = shift;
-    require Apache::Constants;
-    Apache::Constants->import(":common");
-    my $config = $self->config;
-    my %ok = map {$_ => 1} @{$config->{displaying_tables}};
-    return DECLINED() unless exists $ok{$self->{table}};
-
-    # Does the action method exist?
-    my $cv = $self->model_class->can($self->{action});
-    return DECLINED() unless $cv;
-
-    # Is it exported?
-    my $attribs = join " ", attributes::get($cv);
-    return DECLINED() unless $attribs =~ /\b(Exported|Class|Single|Multiple)\b/i;
-    return OK();
-}
+For a full example, see the included "beer database" application.
 
+=head1 HOW IT WORKS
 
-sub authenticate { return 200 }
+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>. 
 
-1;
+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:
+
+    package ProductDatabase::Model;
+    use base 'Apache::MVC::Model::CDBI';
+
+    sub supersearch :Exported {
+        my ($self, $request) = @_;
+        # Do stuff, get a bunch of objects back
+        $r->objects(\@objects);
+        $r->template("template_name");
+    }
+
+    ProductDatabase->config->{model_class} = "ProductDatabase::Model";
+
+(The C<:Exported> attribute means that the method can be called via the
+URL C</I<table>/supersearch/...>.)
+
+Alternatively, you can put the method directly into the specific model
+class for the table:
+
+    sub ProductDatabase::Product::supersearch :Exported { ... }
+
+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.
+
+=head1 AUTHOR
+
+Simon Cozens, C<simon@cpan.org>
+
+=head1 LICENSE
+
+You may distribute this code under the same terms as Perl itself.