2 use base qw(Class::Accessor::Fast Class::Data::Inheritable);
3 use UNIVERSAL::require;
7 use Maypole::Constants;
11 our $VERSION = '2.11';
13 # proposed privacy conventions:
14 # - no leading underscore - public to custom application code and plugins
15 # - single leading underscore - private to the main Maypole stack - *not*
17 # - double leading underscore - private to the current package
21 Maypole - MVC web application framework
25 See L<Maypole::Application>.
29 This documents the Maypole request object. See the L<Maypole::Manual>, for a
30 detailed guide to using Maypole.
32 Maypole is a Perl web application framework similar to Java's struts. It is
33 essentially completely abstracted, and so doesn't know anything about
34 how to talk to the outside world.
36 To use it, you need to create a driver package which represents your entire
37 application. This is the C<BeerDB> package used as an example in the manual.
39 This needs to first use L<Maypole::Application> which will make your package
40 inherit from the appropriate platform driver such as C<Apache::MVC> or
41 C<CGI::Maypole>. Then, the driver calls C<setup>. This sets up the model classes and
42 configures your application. The default model class for Maypole uses
43 L<Class::DBI> to map a database to classes, but this can be changed by altering
44 configuration (B<before> calling setup.)
47 =head1 DOCUMENTATION AND SUPPORT
49 Note that some details in some of these resources may be out of date.
53 =item The Maypole Manual
55 The primary documentation is the Maypole manual. This lives in the
56 C<Maypole::Manual> pod documents included with the distribution.
60 Individual packages within the distribution contain (more or less) detailed
61 reference documentation for their API.
65 There are two mailing lists - maypole-devel and maypole-users - see
66 http://maypole.perl.org/?MailingList
68 =item The Maypole Wiki
70 The Maypole wiki provides a useful store of extra documentation -
71 http://maypole.perl.org
73 In particular, there's a FAQ (http://maypole.perl.org/?FAQ) and a cookbook
74 (http://maypole.perl.org/?Cookbook). Again, certain information on these pages
77 =item Web applications with Maypole
79 A tutorial written by Simon Cozens for YAPC::EU 2005 -
80 http://www.droogs.org/perl/maypole/maypole-tutorial.pdf [228KB].
82 =item A Database-Driven Web Application in 18 Lines of Code
84 By Paul Barry, published in Linux Journal, March 2005.
86 http://www.linuxjournal.com/article/7937
88 "From zero to Web-based database application in eight easy steps".
90 Maypole won a 2005 Linux Journal Editor's Choice Award
91 (http://www.linuxjournal.com/article/8293) after featuring in this article.
93 =item Build Web apps with Maypole
95 By Simon Cozens, on IBM's DeveloperWorks website, May 2004.
97 http://www-128.ibm.com/developerworks/linux/library/l-maypole/
99 =item Rapid Web Application Deployment with Maypole
101 By Simon Cozens, on O'Reilly's Perl website, April 2004.
103 http://www.perl.com/pub/a/2004/04/15/maypole.html
107 Some notes written by Simon Cozens. A little bit out of date, but still
108 very useful: http://www.droogs.org/perl/maypole/authentication.html
112 There's a refcard for the Maypole (and Class::DBI) APIs on the wiki -
113 http://maypole.perl.org/?CheatSheet. Probably a little out of date now - it's a
114 wiki, so feel free to fix any errors!
116 =item Plugins and add-ons
118 There are a large and growing number of plugins and other add-on modules
119 available on CPAN - http://search.cpan.org/search?query=maypole&mode=module
123 You can find a range of useful Maypole links, particularly to several thoughtful
124 blog entries, starting here: http://del.icio.us/search/?all=maypole
128 There are a couple of short reviews here:
129 http://cpanratings.perl.org/dist/Maypole
135 A couple of demos are available, sometimes with source code and configs.
139 =item http://maypole.perl.org/beerdb/
141 The standard BeerDB example, using the TT factory templates supplied in the
144 =item beerdb.riverside-cms.co.uk
146 The standard BeerDB example, running on Mason, using the factory templates
147 supplied in the L<MasonX::Maypole> distribution.
149 =item beerfb.riverside-cms.co.uk
151 A demo of L<Maypole::FormBuilder>. This site is running on the set of Mason
152 templates included in the L<Maypole::FormBuilder> distribution. See the
153 synopsis of L<Maypole::Plugin::FormBuilder> for an example driver
159 __PACKAGE__->mk_classdata($_) for qw( config init_done view_object );
161 __PACKAGE__->mk_accessors(
162 qw( params query objects model_class template_args output path
163 args action template error document_encoding content_type table
164 headers_in headers_out stash session)
167 __PACKAGE__->config( Maypole::Config->new() );
169 __PACKAGE__->init_done(0);
177 Returns the L<Maypole::Config> object
181 My::App->setup($data_source, $user, $password, \%attr);
183 Initialise the Maypole application and plugins and model classes - see
184 L<Maypole::Manual::Plugins>.
186 If your model is based on L<Maypole::Model::CDBI>, the C<\%attr> hashref can
187 contain options that are passed directly to L<Class::DBI::Loader>, to control
188 how the model hierarchy is constructed.
190 Your application should call this B<after> setting up configuration data via
199 $class->setup_model(@_);
204 Called by C<setup>. This method builds the Maypole model hierarchy.
206 A likely target for over-riding, if you need to build a customised model.
212 my $calling_class = shift;
214 $calling_class = ref $calling_class if ref $calling_class;
216 my $config = $calling_class->config;
218 $config->model || $config->model('Maypole::Model::CDBI');
220 $config->model->require or die sprintf
221 "Couldn't load the model class %s: %s", $config->model, $@;
223 $config->model->setup_database($config, $calling_class, @_);
225 foreach my $subclass ( @{ $config->classes } )
228 unshift @{ $subclass . "::ISA" }, $config->model;
229 $config->model->adopt($subclass)
230 if $config->model->can("adopt");
232 # TODO: I think we should also load these classes, in case there is any
233 # custom code. It would save the developer from needing to put
234 # lots of use MyApp::SomeTable statements in the driver, and should
235 # help eliminate some of those annoying silent errors if there's a
242 Loads the view class and instantiates the view object.
244 You should not call this directly, but you may wish to override this to add
245 application-specific initialisation - see L<Maypole::Manual::Plugins>.
252 my $config = $class->config;
253 $config->view || $config->view("Maypole::View::TT");
254 $config->view->require;
255 die "Couldn't load the view class " . $config->view . ": $@" if $@;
256 $config->display_tables
257 || $config->display_tables( $class->config->tables );
258 $class->view_object( $class->config->view->new );
259 $class->init_done(1);
264 Constructs a very minimal new Maypole request object.
274 config => $class->config,
282 Get/set the Maypole::View object
286 sub My::App::debug {1}
288 Returns the debugging flag. Override this in your application class to
289 enable/disable debugging.
291 You can also set the C<debug> flag via L<Maypole::Application>.
297 =item get_template_root
299 Implementation-specific path to template root.
301 You should only need to define this method if you are writing a new Maypole
302 backend. Otherwise, see L<Maypole::Config/"template_root">
306 sub get_template_root {'.'}
310 =head1 INSTANCE METHODS
318 This method sets up the class if it's not done yet, sets some defaults and
319 leaves the dirty work to C<handler_guts>.
323 # handler() has a method attribute so that mod_perl will invoke
324 # BeerDB->handler() as a method rather than a plain function
325 # BeerDB::handler() and so this inherited implementation will be
326 # found. See e.g. "Practical mod_perl" by Bekman & Cholet for
327 # more information <http://modperlbook.org/html/ch25_01.html>
330 # See Maypole::Workflow before trying to understand this.
331 my ($class, $req) = @_;
333 $class->init unless $class->init_done;
335 my $self = $class->new;
337 # initialise the request
338 $self->headers_out(Maypole::Headers->new);
339 $self->get_request($req);
340 $self->parse_location;
342 # hook useful for declining static requests e.g. images
343 my $status = $self->start_request_hook;
344 return $status unless $status == Maypole::Constants::OK();
346 $self->session($self->get_session);
348 $status = $self->handler_guts;
350 # moving this here causes unit test failures - need to check why
351 # before committing the move
352 #$status = $self->__call_process_view unless $self->output;
354 return $status unless $status == OK;
356 # TODO: require send_output to return a status code
364 This is the main request handling method and calls various methods to handle the
365 request/response and defines the workflow within Maypole.
367 B<Currently undocumented and liable to be refactored without warning>.
371 # The root of all evil
378 my $applicable = $self->is_model_applicable;
380 $self->__setup_plain_template unless $applicable;
384 eval { $status = $self->call_authenticate };
386 if ( my $error = $@ )
388 $status = $self->call_exception($error);
392 warn "caught authenticate error: $error";
393 return $self->debug ?
394 $self->view_object->error($self, $error) : ERROR;
398 if ( $self->debug and $status != OK and $status != DECLINED )
400 $self->view_object->error( $self,
401 "Got unexpected status $status from calling authentication" );
404 return $status unless $status == OK;
406 # We run additional_data for every request
407 $self->additional_data;
411 eval { $self->model_class->process($self) };
413 if ( my $error = $@ )
415 $status = $self->call_exception($error);
419 warn "caught model error: $error";
420 return $self->debug ?
421 $self->view_object->error($self, $error) : ERROR;
426 # less frequent path - perhaps output has been set to an error message
427 return OK if $self->output;
429 # normal path - no output has been generated yet
430 return $self->__call_process_view;
436 $self->model_class( $self->config->model->class_of($self, $self->table) );
439 # is_applicable() returned false, so set up a plain template. Model processing
440 # will be skipped, but need to remove the model anyway so the template can't
442 sub __setup_plain_template
446 # It's just a plain template
447 $self->model_class(undef);
449 my $path = $self->path;
450 $path =~ s{/$}{}; # De-absolutify
453 $self->template($self->path);
456 # The model has been processed or skipped (if is_applicable returned false),
457 # any exceptions have been handled, and there's no content in $self->output
458 sub __call_process_view
464 eval { $status = $self->view_object->process($self) };
466 if ( my $error = $@ )
468 $status = $self->call_exception($error);
472 warn "caught view error: $error" if $self->debug;
473 return $self->debug ?
474 $self->view_object->error($self, $error) : ERROR;
483 You should only need to define this method if you are writing a new
484 Maypole backend. It should return something that looks like an Apache
485 or CGI request object, it defaults to blank.
493 Turns the backend request (e.g. Apache::MVC, Maypole, CGI) into a Maypole
494 request. It does this by setting the C<path>, and invoking C<parse_path> and
497 You should only need to define this method if you are writing a new Maypole
504 die "parse_location is a virtual method. Do not use Maypole directly; " .
505 "use Apache::MVC or similar";
508 =item start_request_hook
510 This is called immediately after setting up the basic request. The default
511 method simply returns C<Maypole::Constants::OK>.
513 Any other return value causes Maypole to abort further processing of the
514 request. This is useful for filtering out requests for static files, e.g.
515 images, which should not be processed by Maypole or by the templating engine:
517 sub start_request_hook
521 return Maypole::Constants::DECLINED if $r->path =~ /\.jpg$/;
522 return Maypole::Constants::OK;
527 sub start_request_hook { Maypole::Constants::OK }
531 B<This method is deprecated> as of version 2.11. If you have overridden it,
532 please override C<is_model_applicable> instead, and change the return type
533 from a Maypole:Constant to a true/false value.
535 Returns a Maypole::Constant to indicate whether the request is valid.
537 =item is_model_applicable
539 Returns true or false to indicate whether the request is valid.
541 The default implementation checks that C<< $r->table >> is publicly
542 accessible and that the model class is configured to handle the
547 sub is_model_applicable
551 # cater for applications that are using obsolete version
552 if ($self->can('is_applicable'))
554 warn "DEPRECATION WARNING: rewrite is_applicable to the interface ".
555 "of Maypole::is_model_applicable\n";
556 return $self->is_applicable == OK;
559 # Establish which tables should be processed by the model
560 my $config = $self->config;
562 $config->ok_tables || $config->ok_tables( $config->display_tables );
564 $config->ok_tables( { map { $_ => 1 } @{ $config->ok_tables } } )
565 if ref $config->ok_tables eq "ARRAY";
567 my $ok_tables = $config->ok_tables;
569 # Does this request concern a table to be processed by the model?
570 my $table = $self->table;
574 if (exists $ok_tables->{$table})
581 warn "We don't have that table ($table).\n"
582 . "Available tables are: "
583 . join( ",", keys %$ok_tables )
584 if $self->debug and not $ok_tables->{$table};
589 # Is the action public?
590 my $action = $self->action;
591 return 1 if $self->model_class->is_public($action);
593 warn "The action '$action' is not applicable to the table $table"
601 The default method is empty.
607 =item call_authenticate
609 This method first checks if the relevant model class
610 can authenticate the user, or falls back to the default
611 authenticate method of your Maypole application.
615 sub call_authenticate
619 # Check if we have a model class with an authenticate() to delegate to
620 return $self->model_class->authenticate($self)
621 if $self->model_class and $self->model_class->can('authenticate');
623 # Interface consistency is a Good Thing -
624 # the invocant and the argument may one day be different things
625 # (i.e. controller and request), like they are when authenticate()
626 # is called on a model class (i.e. model and request)
627 return $self->authenticate($self);
632 Returns a Maypole::Constant to indicate whether the user is authenticated for
635 The default implementation returns C<OK>
639 sub authenticate { return OK }
644 This model is called to catch exceptions, first after authenticate, then after
645 processing the model class, and finally to check for exceptions from the view
648 This method first checks if the relevant model class
649 can handle exceptions the user, or falls back to the default
650 exception method of your Maypole application.
656 my ($self, $error) = @_;
658 # Check if we have a model class with an exception() to delegate to
659 if ( $self->model_class && $self->model_class->can('exception') )
661 my $status = $self->model_class->exception( $self, $error );
662 return $status if $status == OK;
665 return $self->exception($error);
670 This method is called if any exceptions are raised during the authentication or
671 model/view processing. It should accept the exception as a parameter and return
672 a Maypole::Constant to indicate whether the request should continue to be
677 sub exception { return ERROR }
679 =item additional_data
681 Called before the model processes the request, this method gives you a chance to
682 do some processing for each request, for example, manipulating C<template_args>.
686 sub additional_data { }
690 Sends the output and additional headers to the user.
695 die "send_output is a virtual method. Do not use Maypole directly; use Apache::MVC or similar";
703 =head2 Path processing and manipulation
709 Returns the request path
713 Parses the request path and sets the C<args>, C<action> and C<table>
714 properties. Calls C<preprocess_path> before parsing path and setting properties.
722 # Previous versions unconditionally set table, action and args to whatever
723 # was in @pi (or else to defaults, if @pi is empty).
724 # Adding preprocess_path(), and then setting table, action and args
725 # conditionally, broke lots of tests, hence this:
726 $self->$_(undef) for qw/action table args/;
728 $self->preprocess_path;
730 $self->path || $self->path('frontpage');
732 my @pi = grep {length} split '/', $self->path;
734 $self->table || $self->table(shift @pi);
735 $self->action || $self->action( shift @pi or 'index' );
736 $self->args || $self->args(\@pi);
739 =item preprocess_path
741 Sometimes when you don't want to rewrite or over-ride parse_path but
742 want to rewrite urls or extract data from them before it is parsed.
744 This method is called after parse_location has populated the request
745 information and before parse_path has populated the model and action
746 information, and is passed the request object.
748 You can set action, args or table in this method and parse_path will
749 then leave those values in place or populate them if not present
753 sub preprocess_path { };
755 =item make_path( %args or \%args or @args )
757 This is the counterpart to C<parse_path>. It generates a path to use
758 in links, form actions etc. To implement your own path scheme, just override
759 this method and C<parse_path>.
761 %args = ( table => $table,
763 additional => $additional, # optional - generally an object ID
766 \%args = as above, but a ref
768 @args = ( $table, $action, $additional ); # $additional is optional
770 C<id> can be used as an alternative key to C<additional>.
772 C<$additional> can be a string, an arrayref, or a hashref. An arrayref is
773 expanded into extra path elements, whereas a hashref is translated into a query
784 if (@_ == 1 and ref $_[0] and ref $_[0] eq 'HASH')
788 elsif ( @_ > 1 and @_ < 4 )
790 $args{table} = shift;
791 $args{action} = shift;
792 $args{additional} = shift;
799 do { die "no $_" unless $args{$_} } for qw( table action );
801 my $additional = $args{additional} || $args{id};
807 # if $additional is a href, make_uri() will transform it into a query
808 @add = (ref $additional eq 'ARRAY') ? @$additional : ($additional);
811 my $uri = $r->make_uri($args{table}, $args{action}, @add);
813 return $uri->as_string;
818 =item make_uri( @segments )
820 Make a L<URI> object given table, action etc. Automatically adds
823 If the final element in C<@segments> is a hash ref, C<make_uri> will render it
830 my ($r, @segments) = @_;
832 my $query = (ref $segments[-1] eq 'HASH') ? pop(@segments) : undef;
834 my $base = $r->config->uri_base;
837 my $uri = URI->new($base);
838 $uri->path_segments($uri->path_segments, grep {length} @segments);
840 my $abs_uri = $uri->abs('/');
841 $abs_uri->query_form($query) if $query;
847 Turns post data and query string paramaters into a hash of C<params>.
849 You should only need to define this method if you are writing a new Maypole
854 =head2 Request properties
860 Returns the perl package name that will serve as the model for the
861 request. It corresponds to the request C<table> attribute.
866 Get/set a list of model objects. The objects will be accessible in the view
869 If the first item in C<$self-E<gt>args> can be C<retrieve()>d by the model
870 class, it will be removed from C<args> and the retrieved object will be added to
871 the C<objects> list. See L<Maypole::Model> for more information.
875 $self->template_args->{foo} = 'bar';
877 Get/set a hash of template variables.
881 A place to put custom application data. Not used by Maypole itself.
885 Get/set the template to be used by the view. By default, it returns
891 Get/set a request error
895 Get/set the response output. This is usually populated by the view class. You
896 can skip view processing by setting the C<output>.
900 The table part of the Maypole request path
904 The action part of the Maypole request path
908 A list of remaining parts of the request path after table and action
914 A L<Maypole::Headers> object containing HTTP headers for the request
918 A L<HTTP::Headers> object that contains HTTP headers for the output
920 =item document_encoding
922 Get/set the output encoding. Default: utf-8.
926 Get/set the output content type. Default: text/html
930 Returns the protocol the request was made with, i.e. https
935 die "get_protocol is a virtual method. Do not use Maypole directly; use Apache::MVC or similar";
940 =head2 Request parameters
942 The source of the parameters may vary depending on the Maypole backend, but they
943 are usually populated from request query string and POST data.
945 Maypole supplies several approaches for accessing the request parameters. Note
946 that the current implementation (via a hashref) of C<query> and C<params> is
947 likely to change in a future version of Maypole. So avoid direct access to these
950 $r->{params}->{foo} # bad
951 $r->params->{foo} # better
953 $r->{query}->{foo} # bad
954 $r->query->{foo} # better
956 $r->param('foo') # best
962 An accessor (get or set) for request parameters. It behaves similarly to
963 CGI::param() for accessing CGI parameters, i.e.
965 $r->param # returns list of keys
966 $r->param($key) # returns value for $key
967 $r->param($key => $value) # returns old value, sets to new value
973 my ($self, $key) = (shift, shift);
975 return keys %{$self->params} unless defined $key;
977 return unless exists $self->params->{$key};
979 my $val = $self->params->{$key};
984 $self->params->{$key} = $new_val;
987 return ref $val ? @$val : ($val) if wantarray;
989 return ref $val ? $val->[0] : $val;
995 Returns a hashref of request parameters.
997 B<Note:> Where muliple values of a parameter were supplied, the C<params> value
998 will be an array reference.
1002 Alias for C<params>.
1006 =head3 Utility methods
1008 =item redirect_request
1010 Sets output headers to redirect based on the arguments provided
1012 Accepts either a single argument of the full url to redirect to, or a hash of
1015 $r->redirect_request('http://www.example.com/path');
1019 $r->redirect_request(protocol=>'https', domain=>'www.example.com', path=>'/path/file?arguments', status=>'302', url=>'..');
1021 The named parameters are protocol, domain, path, status and url
1023 Only 1 named parameter is required but other than url, they can be combined as
1024 required and current values (from the request) will be used in place of any
1025 missing arguments. The url argument must be a full url including protocol and
1026 can only be combined with status.
1030 sub redirect_request {
1031 die "redirect_request is a virtual method. Do not use Maypole directly; use Apache::MVC or similar";
1034 =item redirect_internal_request
1038 sub redirect_internal_request {
1043 =item make_random_id
1045 returns a unique id for this request can be used to prevent or detect repeat
1050 # Session and Repeat Submission Handling
1051 sub make_random_id {
1052 use Maypole::Session;
1053 return Maypole::Session::generate_unique_id();
1060 There's more documentation, examples, and a information on our mailing lists
1061 at the Maypole web site:
1063 L<http://maypole.perl.org/>
1065 L<Maypole::Application>, L<Apache::MVC>, L<CGI::Maypole>.
1069 Maypole is currently maintained by Aaron Trevena
1071 =head1 AUTHOR EMERITUS
1073 Simon Cozens, C<simon#cpan.org>
1075 Sebastian Riedel, C<sri#oook.de> maintained Maypole from 1.99_01 to 2.04
1079 Sebastian Riedel, Danijel Milicevic, Dave Slack, Jesse Sheidlower, Jody Belka,
1080 Marcus Ramberg, Mickael Joanne, Randal Schwartz, Simon Flack, Steve Simms,
1081 Veljko Vidovic and all the others who've helped.
1085 You may distribute this code under the same terms as Perl itself.