2 use base qw(Class::Accessor Class::Data::Inheritable);
4 use Class::DBI::Loader;
5 use UNIVERSAL::require;
6 use Apache::Constants ":common";
10 __PACKAGE__->mk_classdata($_) for qw( config init_done view_object );
11 __PACKAGE__->mk_accessors ( qw( ar params query objects model_class
12 args action template ));
13 __PACKAGE__->config({});
14 __PACKAGE__->init_done(0);
19 if ($real ne "Apache::MVC") {
21 *{$real."::handler"} = sub { Apache::MVC::handler($real, @_) };
26 my ($calling_class, $dsn) = @_;
27 $calling_class = ref $calling_class if ref $calling_class;
28 my $config = $calling_class->config;
29 $config->{model} ||= "Apache::MVC::Model::CDBI";
30 $config->{model}->require;
31 $config->{dsn} = $dsn;
32 $config->{loader} = Class::DBI::Loader->new(
33 namespace => $calling_class,
36 $config->{classes} = [ $config->{loader}->classes ];
37 for my $subclass (@{$config->{classes}}) {
39 unshift @{$subclass."::ISA"}, $config->{model};
40 $config->{model}->adopt($subclass)
41 if $config->{model}->can("adopt");
47 my $config = $class->config;
48 $config->{view} ||= "Apache::MVC::View::TT";
49 $config->{view}->require;
50 $config->{display_tables} ||= [ $class->config->{loader}->tables ];
51 $class->view_object($class->config->{view}->new);
57 my ($self, $table) = @_;
58 return $self->config->{loader}->_table2class($table);
62 # See Apache::MVC::Workflow before trying to understand this.
64 $class->init unless $class->init_done;
65 my $r = bless { config => $class->config }, $class;
69 $r->model_class($r->class_of($r->{table}));
70 my $status = $r->is_applicable;
72 $status = $r->call_authenticate;
73 return $status unless $status == OK;
74 $r->additional_data();
76 $r->model_class->process($r);
78 # Otherwise, it's just a plain template.
79 delete $r->{model_class};
80 $r->{path} =~ s{/}{}; # De-absolutify
81 $r->template($r->{path});
83 return $r->view_object->process($r);
88 require Apache; require Apache::Request;
89 $self->{ar} = Apache::Request->new(Apache->request);
94 $self->{path} = $self->{ar}->uri;
95 my $loc = $self->{ar}->location;
96 $self->{path} =~ s/^$loc//; # I shouldn't need to do this?
97 $self->{path} ||= "frontpage";
98 my @pi = split /\//, $self->{path};
99 shift @pi while @pi and !$pi[0];
100 $self->{table} = shift @pi;
101 $self->{action} = shift @pi;
102 $self->{args} = \@pi;
104 $self->{params} = { $self->{ar}->content };
105 $self->{query} = { $self->{ar}->args };
110 my $config = $self->config;
111 $config->{ok_tables} = {map {$_ => 1} @{$config->{display_tables}}};
112 warn "We don't have that table ($self->{table})"
113 unless $config->{ok_tables}{$self->{table}};
114 return DECLINED() unless exists $config->{ok_tables}{$self->{table}};
116 # Does the action method exist?
117 my $cv = $self->model_class->can($self->{action});
118 warn "We don't have that action ($self->{action})" unless $cv;
119 return DECLINED() unless $cv;
122 $self->{method_attribs} = join " ", attributes::get($cv);
123 do { warn "$self->{action} not exported";
125 } unless $self->{method_attribs} =~ /\bExported\b/i;
129 sub call_authenticate {
131 return $self->model_class->authenticate($self) if
132 $self->model_class->can("authenticate");
133 return $self->authenticate();
136 sub additional_data {}
138 sub authenticate { return OK }
144 Maypole - MVC web application framework
152 A large number of web programming tasks follow the same sort of pattern:
153 we have some data in a datasource, typically a relational database. We
154 have a bunch of templates provided by web designers. We have a number of
155 things we want to be able to do with the database - create, add, edit,
156 delete records, view records, run searches, and so on. We have a web
157 server which provides input from the user about what to do. Something in
158 the middle takes the input, grabs the relevant rows from the database,
159 performs the action, constructs a page, and spits it out.
161 Maypole aims to be the most generic and extensible "something in the
162 middle" - an MVC-based web application framework.
164 An example would help explain this best. You need to add a product
165 catalogue to a company's web site. Users need to list the products in
166 various categories, view a page on each product with its photo and
167 pricing information and so on, and there needs to be a back-end where
168 sales staff can add new lines, change prices, and delete out of date
169 records. So, you set up the database, provide some default templates
170 for the designers to customize, and then write an Apache handler like
173 package ProductDatabase;
174 use base 'Apache::MVC';
175 __PACKAGE__->set_database("dbi:mysql:products");
176 BeerDB->config->{uri_base} = "http://your.site/catalogue/";
177 ProductDatabase::Product->has_a("category" => ProductDatabase::Category);
181 my ($self, $request) = @_;
182 return OK if $request->{ar}->get_remote_host() eq "sales.yourcorp.com";
183 return OK if $request->{action} =~ /^(view|list)$/;
188 You then put the following in your Apache config:
190 <Location /catalogue>
191 SetHandler perl-script
192 PerlHandler ProductDatabase
195 And copy the templates found in F<templates/factory> into the
196 F<catalogue/factory> directory off the web root. When the designers get
197 back to you with custom templates, they are to go in
198 F<catalogue/custom>. If you need to do override templates on a
199 database-table-by-table basis, put the new template in
200 F<catalogue/I<table>>.
202 This will automatically give you C<add>, C<edit>, C<list>, C<view> and
203 C<delete> commands; for instance, a product list, go to
205 http://your.site/catalogue/product/list
207 For a full example, see the included "beer database" application.
211 There's some documentation for the workflow in L<Apache::MVC::Workflow>,
212 but the basic idea is that a URL part like C<product/list> gets
213 translated into a call to C<ProductDatabase::Product-E<gt>list>. This
214 propagates the request with a set of objects from the database, and then
215 calls the C<list> template; first, a C<product/list> template if it
216 exists, then the C<custom/list> and finally C<factory/list>.
218 If there's another action you want the system to do, you need to either
219 subclass the model class, and configure your class slightly differently:
221 package ProductDatabase::Model;
222 use base 'Apache::MVC::Model::CDBI';
224 sub supersearch :Exported {
225 my ($self, $request) = @_;
226 # Do stuff, get a bunch of objects back
227 $r->objects(\@objects);
228 $r->template("template_name");
231 ProductDatabase->config->{model_class} = "ProductDatabase::Model";
233 (The C<:Exported> attribute means that the method can be called via the
234 URL C</I<table>/supersearch/...>.)
236 Alternatively, you can put the method directly into the specific model
239 sub ProductDatabase::Product::supersearch :Exported { ... }
241 By default, the view class uses Template Toolkit as the template
242 processor, and the model class uses C<Class::DBI>; it may help you to be
243 familiar with these modules before going much further with this,
244 although I expect there to be other subclasses for other templating
245 systems and database abstraction layers as time goes on. The article at
246 C<http://www.perl.com/pub/a/2003/07/15/nocode.html> is a great
247 introduction to the process we're trying to automate.
251 Simon Cozens, C<simon@cpan.org>
255 You may distribute this code under the same terms as Perl itself.