X-Git-Url: https://git.decadent.org.uk/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2FApache%2FMVC.pm;h=4b1a60005750c186b7659cdefa224e01b72afee0;hb=d4dc7a8a0ca5bf94fddf2653ed611eec11bb4c89;hp=467f0f97b83ffb5f01c2d55b59a3bb191c3513f8;hpb=d635ca733a7199c4f9893e8d5a50e96a1295f092;p=maypole.git

diff --git a/lib/Apache/MVC.pm b/lib/Apache/MVC.pm
index 467f0f9..4b1a600 100644
--- a/lib/Apache/MVC.pm
+++ b/lib/Apache/MVC.pm
@@ -6,7 +6,7 @@ use UNIVERSAL::require;
 use Apache::Constants ":common";
 use strict;
 use warnings;
-our $VERSION = "1.0";
+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 ));
@@ -75,14 +75,19 @@ sub handler {
 
     $r->model_class($r->class_of($r->{table}));
     my $status = $r->is_applicable;
-    return $status unless $status == OK;
-    $status = $r->call_authenticate;
-    return $status unless $status == OK;
-    $r->additional_data();
+    if ($status == OK) { 
+        $status = $r->call_authenticate;
+        return $status unless $status == OK;
+        $r->additional_data();
     
-    $r->model_class->process($r);
-    $r->view_object->process($r);
-    return $r; # For debugging.
+        $r->model_class->process($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);
 }
 
 sub get_request {
@@ -93,8 +98,11 @@ sub get_request {
 
 sub parse_location {
     my $self = shift;
-    my $uri = $self->{ar}->path_info();
-    my @pi = split /\//, $uri;
+    $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;
@@ -112,7 +120,6 @@ sub is_applicable {
     return DECLINED() unless exists $config->{ok_tables}{$self->{table}};
 
     # Does the action method exist?
-    # XXX We should set the method class to the class for the table
     my $cv = $self->model_class->can($self->{action});
     warn "We don't have that action ($self->{action})" unless $cv;
     return DECLINED() unless $cv;
@@ -137,3 +144,128 @@ sub additional_data {}
 sub authenticate { return OK }
 
 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;
+    }
+    1;
+
+You then put the following in your Apache config:
+
+    <Location /catalogue>
+        SetHandler perl-script
+        PerlHandler ProductDatabase
+    </Location>
+
+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>>. 
+
+This will automatically give you C<add>, C<edit>, C<list>, C<view> and
+C<delete> commands; for instance, a product list, go to 
+
+    http://your.site/catalogue/product/list
+
+For a full example, see the included "beer database" application.
+
+=head1 HOW IT WORKS
+
+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>. 
+
+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.