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49 Note that some details in some of these resources may be out of date.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.
208 This method also ensures any code in custom model classes is loaded, so you
209 don't need to load them in the driver.
217 $class = ref $class if ref $class;
219 my $config = $class->config;
221 $config->model || $config->model('Maypole::Model::CDBI');
223 $config->model->require or die sprintf
224 "Couldn't load the model class %s: %s", $config->model, $@;
226 # among other things, this populates $config->classes
227 $config->model->setup_database($config, $class, @_);
229 foreach my $subclass ( @{ $config->classes } )
232 unshift @{ $subclass . "::ISA" }, $config->model;
233 $config->model->adopt($subclass)
234 if $config->model->can("adopt");
236 # Load custom model code, if it exists - nb this must happen after the
237 # unshift, to allow code attributes to work
238 eval "use $subclass";
239 die "Error loading $subclass: $@"
240 if $@ and $@ !~ /Can\'t locate \S+ in \@INC/;
246 Loads the view class and instantiates the view object.
248 You should not call this directly, but you may wish to override this to add
249 application-specific initialisation - see L<Maypole::Manual::Plugins>.
256 my $config = $class->config;
257 $config->view || $config->view("Maypole::View::TT");
258 $config->view->require;
259 die "Couldn't load the view class " . $config->view . ": $@" if $@;
260 $config->display_tables
261 || $config->display_tables( $class->config->tables );
262 $class->view_object( $class->config->view->new );
263 $class->init_done(1);
268 Constructs a very minimal new Maypole request object.
278 config => $class->config,
286 Get/set the Maypole::View object
290 sub My::App::debug {1}
292 Returns the debugging flag. Override this in your application class to
293 enable/disable debugging.
295 You can also set the C<debug> flag via L<Maypole::Application>.
301 =item get_template_root
303 Implementation-specific path to template root.
305 You should only need to define this method if you are writing a new Maypole
306 backend. Otherwise, see L<Maypole::Config/"template_root">
310 sub get_template_root {'.'}
314 =head1 INSTANCE METHODS
322 This method sets up the class if it's not done yet, sets some defaults and
323 leaves the dirty work to C<handler_guts>.
327 # handler() has a method attribute so that mod_perl will invoke
328 # BeerDB->handler() as a method rather than a plain function
329 # BeerDB::handler() and so this inherited implementation will be
330 # found. See e.g. "Practical mod_perl" by Bekman & Cholet for
331 # more information <http://modperlbook.org/html/ch25_01.html>
334 # See Maypole::Workflow before trying to understand this.
335 my ($class, $req) = @_;
337 $class->init unless $class->init_done;
339 my $self = $class->new;
341 # initialise the request
342 $self->headers_out(Maypole::Headers->new);
343 $self->get_request($req);
344 $self->parse_location;
346 # hook useful for declining static requests e.g. images
347 my $status = $self->start_request_hook;
348 return $status unless $status == Maypole::Constants::OK();
350 $self->session($self->get_session);
352 $status = $self->handler_guts;
354 # moving this here causes unit test failures - need to check why
355 # before committing the move
356 #$status = $self->__call_process_view unless $self->output;
358 return $status unless $status == OK;
360 # TODO: require send_output to return a status code
368 This is the main request handling method and calls various methods to handle the
369 request/response and defines the workflow within Maypole.
371 B<Currently undocumented and liable to be refactored without warning>.
375 # The root of all evil
382 my $applicable = $self->is_model_applicable;
384 $self->__setup_plain_template unless $applicable;
388 eval { $status = $self->call_authenticate };
390 if ( my $error = $@ )
392 $status = $self->call_exception($error);
396 warn "caught authenticate error: $error";
397 return $self->debug ?
398 $self->view_object->error($self, $error) : ERROR;
402 if ( $self->debug and $status != OK and $status != DECLINED )
404 $self->view_object->error( $self,
405 "Got unexpected status $status from calling authentication" );
408 return $status unless $status == OK;
410 # We run additional_data for every request
411 $self->additional_data;
415 eval { $self->model_class->process($self) };
417 if ( my $error = $@ )
419 $status = $self->call_exception($error);
423 warn "caught model error: $error";
424 return $self->debug ?
425 $self->view_object->error($self, $error) : ERROR;
430 # less frequent path - perhaps output has been set to an error message
431 return OK if $self->output;
433 # normal path - no output has been generated yet
434 return $self->__call_process_view;
440 $self->model_class( $self->config->model->class_of($self, $self->table) );
443 # is_applicable() returned false, so set up a plain template. Model processing
444 # will be skipped, but need to remove the model anyway so the template can't
446 sub __setup_plain_template
450 # It's just a plain template
451 $self->model_class(undef);
453 my $path = $self->path;
454 $path =~ s{/$}{}; # De-absolutify
457 $self->template($self->path);
460 # The model has been processed or skipped (if is_applicable returned false),
461 # any exceptions have been handled, and there's no content in $self->output
462 sub __call_process_view
468 eval { $status = $self->view_object->process($self) };
470 if ( my $error = $@ )
472 $status = $self->call_exception($error);
476 warn "caught view error: $error" if $self->debug;
477 return $self->debug ?
478 $self->view_object->error($self, $error) : ERROR;
487 You should only need to define this method if you are writing a new
488 Maypole backend. It should return something that looks like an Apache
489 or CGI request object, it defaults to blank.
497 Turns the backend request (e.g. Apache::MVC, Maypole, CGI) into a Maypole
498 request. It does this by setting the C<path>, and invoking C<parse_path> and
501 You should only need to define this method if you are writing a new Maypole
508 die "parse_location is a virtual method. Do not use Maypole directly; " .
509 "use Apache::MVC or similar";
512 =item start_request_hook
514 This is called immediately after setting up the basic request. The default
515 method simply returns C<Maypole::Constants::OK>.
517 Any other return value causes Maypole to abort further processing of the
518 request. This is useful for filtering out requests for static files, e.g.
519 images, which should not be processed by Maypole or by the templating engine:
521 sub start_request_hook
525 return Maypole::Constants::DECLINED if $r->path =~ /\.jpg$/;
526 return Maypole::Constants::OK;
531 sub start_request_hook { Maypole::Constants::OK }
535 B<This method is deprecated> as of version 2.11. If you have overridden it,
536 please override C<is_model_applicable> instead, and change the return type
537 from a Maypole:Constant to a true/false value.
539 Returns a Maypole::Constant to indicate whether the request is valid.
541 =item is_model_applicable
543 Returns true or false to indicate whether the request is valid.
545 The default implementation checks that C<< $r->table >> is publicly
546 accessible and that the model class is configured to handle the
551 sub is_model_applicable
555 # cater for applications that are using obsolete version
556 if ($self->can('is_applicable'))
558 warn "DEPRECATION WARNING: rewrite is_applicable to the interface ".
559 "of Maypole::is_model_applicable\n";
560 return $self->is_applicable == OK;
563 # Establish which tables should be processed by the model
564 my $config = $self->config;
566 $config->ok_tables || $config->ok_tables( $config->display_tables );
568 $config->ok_tables( { map { $_ => 1 } @{ $config->ok_tables } } )
569 if ref $config->ok_tables eq "ARRAY";
571 my $ok_tables = $config->ok_tables;
573 # Does this request concern a table to be processed by the model?
574 my $table = $self->table;
578 if (exists $ok_tables->{$table})
585 warn "We don't have that table ($table).\n"
586 . "Available tables are: "
587 . join( ",", keys %$ok_tables )
588 if $self->debug and not $ok_tables->{$table};
593 # Is the action public?
594 my $action = $self->action;
595 return 1 if $self->model_class->is_public($action);
597 warn "The action '$action' is not applicable to the table $table"
605 The default method is empty.
611 =item call_authenticate
613 This method first checks if the relevant model class
614 can authenticate the user, or falls back to the default
615 authenticate method of your Maypole application.
619 sub call_authenticate
623 # Check if we have a model class with an authenticate() to delegate to
624 return $self->model_class->authenticate($self)
625 if $self->model_class and $self->model_class->can('authenticate');
627 # Interface consistency is a Good Thing -
628 # the invocant and the argument may one day be different things
629 # (i.e. controller and request), like they are when authenticate()
630 # is called on a model class (i.e. model and request)
631 return $self->authenticate($self);
636 Returns a Maypole::Constant to indicate whether the user is authenticated for
639 The default implementation returns C<OK>
643 sub authenticate { return OK }
648 This model is called to catch exceptions, first after authenticate, then after
649 processing the model class, and finally to check for exceptions from the view
652 This method first checks if the relevant model class
653 can handle exceptions the user, or falls back to the default
654 exception method of your Maypole application.
660 my ($self, $error) = @_;
662 # Check if we have a model class with an exception() to delegate to
663 if ( $self->model_class && $self->model_class->can('exception') )
665 my $status = $self->model_class->exception( $self, $error );
666 return $status if $status == OK;
669 return $self->exception($error);
674 This method is called if any exceptions are raised during the authentication or
675 model/view processing. It should accept the exception as a parameter and return
676 a Maypole::Constant to indicate whether the request should continue to be
681 sub exception { return ERROR }
683 =item additional_data
685 Called before the model processes the request, this method gives you a chance to
686 do some processing for each request, for example, manipulating C<template_args>.
690 sub additional_data { }
694 Sends the output and additional headers to the user.
699 die "send_output is a virtual method. Do not use Maypole directly; use Apache::MVC or similar";
707 =head2 Path processing and manipulation
713 Returns the request path
717 Parses the request path and sets the C<args>, C<action> and C<table>
718 properties. Calls C<preprocess_path> before parsing path and setting properties.
726 # Previous versions unconditionally set table, action and args to whatever
727 # was in @pi (or else to defaults, if @pi is empty).
728 # Adding preprocess_path(), and then setting table, action and args
729 # conditionally, broke lots of tests, hence this:
730 $self->$_(undef) for qw/action table args/;
732 $self->preprocess_path;
734 $self->path || $self->path('frontpage');
736 my @pi = grep {length} split '/', $self->path;
738 $self->table || $self->table(shift @pi);
739 $self->action || $self->action( shift @pi or 'index' );
740 $self->args || $self->args(\@pi);
743 =item preprocess_path
745 Sometimes when you don't want to rewrite or over-ride parse_path but
746 want to rewrite urls or extract data from them before it is parsed.
748 This method is called after parse_location has populated the request
749 information and before parse_path has populated the model and action
750 information, and is passed the request object.
752 You can set action, args or table in this method and parse_path will
753 then leave those values in place or populate them if not present
757 sub preprocess_path { };
759 =item make_path( %args or \%args or @args )
761 This is the counterpart to C<parse_path>. It generates a path to use
762 in links, form actions etc. To implement your own path scheme, just override
763 this method and C<parse_path>.
765 %args = ( table => $table,
767 additional => $additional, # optional - generally an object ID
770 \%args = as above, but a ref
772 @args = ( $table, $action, $additional ); # $additional is optional
774 C<id> can be used as an alternative key to C<additional>.
776 C<$additional> can be a string, an arrayref, or a hashref. An arrayref is
777 expanded into extra path elements, whereas a hashref is translated into a query
788 if (@_ == 1 and ref $_[0] and ref $_[0] eq 'HASH')
792 elsif ( @_ > 1 and @_ < 4 )
794 $args{table} = shift;
795 $args{action} = shift;
796 $args{additional} = shift;
803 do { die "no $_" unless $args{$_} } for qw( table action );
805 my $additional = $args{additional} || $args{id};
811 # if $additional is a href, make_uri() will transform it into a query
812 @add = (ref $additional eq 'ARRAY') ? @$additional : ($additional);
815 my $uri = $r->make_uri($args{table}, $args{action}, @add);
817 return $uri->as_string;
822 =item make_uri( @segments )
824 Make a L<URI> object given table, action etc. Automatically adds
827 If the final element in C<@segments> is a hash ref, C<make_uri> will render it
834 my ($r, @segments) = @_;
836 my $query = (ref $segments[-1] eq 'HASH') ? pop(@segments) : undef;
838 my $base = $r->config->uri_base;
841 my $uri = URI->new($base);
842 $uri->path_segments($uri->path_segments, grep {length} @segments);
844 my $abs_uri = $uri->abs('/');
845 $abs_uri->query_form($query) if $query;
851 Turns post data and query string paramaters into a hash of C<params>.
853 You should only need to define this method if you are writing a new Maypole
858 =head2 Request properties
864 Returns the perl package name that will serve as the model for the
865 request. It corresponds to the request C<table> attribute.
870 Get/set a list of model objects. The objects will be accessible in the view
873 If the first item in C<$self-E<gt>args> can be C<retrieve()>d by the model
874 class, it will be removed from C<args> and the retrieved object will be added to
875 the C<objects> list. See L<Maypole::Model> for more information.
879 $self->template_args->{foo} = 'bar';
881 Get/set a hash of template variables.
885 A place to put custom application data. Not used by Maypole itself.
889 Get/set the template to be used by the view. By default, it returns
895 Get/set a request error
899 Get/set the response output. This is usually populated by the view class. You
900 can skip view processing by setting the C<output>.
904 The table part of the Maypole request path
908 The action part of the Maypole request path
912 A list of remaining parts of the request path after table and action
918 A L<Maypole::Headers> object containing HTTP headers for the request
922 A L<HTTP::Headers> object that contains HTTP headers for the output
924 =item document_encoding
926 Get/set the output encoding. Default: utf-8.
930 Get/set the output content type. Default: text/html
934 Returns the protocol the request was made with, i.e. https
939 die "get_protocol is a virtual method. Do not use Maypole directly; use Apache::MVC or similar";
944 =head2 Request parameters
946 The source of the parameters may vary depending on the Maypole backend, but they
947 are usually populated from request query string and POST data.
949 Maypole supplies several approaches for accessing the request parameters. Note
950 that the current implementation (via a hashref) of C<query> and C<params> is
951 likely to change in a future version of Maypole. So avoid direct access to these
954 $r->{params}->{foo} # bad
955 $r->params->{foo} # better
957 $r->{query}->{foo} # bad
958 $r->query->{foo} # better
960 $r->param('foo') # best
966 An accessor (get or set) for request parameters. It behaves similarly to
967 CGI::param() for accessing CGI parameters, i.e.
969 $r->param # returns list of keys
970 $r->param($key) # returns value for $key
971 $r->param($key => $value) # returns old value, sets to new value
977 my ($self, $key) = (shift, shift);
979 return keys %{$self->params} unless defined $key;
981 return unless exists $self->params->{$key};
983 my $val = $self->params->{$key};
988 $self->params->{$key} = $new_val;
991 return ref $val ? @$val : ($val) if wantarray;
993 return ref $val ? $val->[0] : $val;
999 Returns a hashref of request parameters.
1001 B<Note:> Where muliple values of a parameter were supplied, the C<params> value
1002 will be an array reference.
1006 Alias for C<params>.
1010 =head3 Utility methods
1014 =item redirect_request
1016 Sets output headers to redirect based on the arguments provided
1018 Accepts either a single argument of the full url to redirect to, or a hash of
1021 $r->redirect_request('http://www.example.com/path');
1025 $r->redirect_request(protocol=>'https', domain=>'www.example.com', path=>'/path/file?arguments', status=>'302', url=>'..');
1027 The named parameters are protocol, domain, path, status and url
1029 Only 1 named parameter is required but other than url, they can be combined as
1030 required and current values (from the request) will be used in place of any
1031 missing arguments. The url argument must be a full url including protocol and
1032 can only be combined with status.
1036 sub redirect_request {
1037 die "redirect_request is a virtual method. Do not use Maypole directly; use Apache::MVC or similar";
1040 =item redirect_internal_request
1044 sub redirect_internal_request {
1049 =item make_random_id
1051 returns a unique id for this request can be used to prevent or detect repeat
1056 # Session and Repeat Submission Handling
1057 sub make_random_id {
1058 use Maypole::Session;
1059 return Maypole::Session::generate_unique_id();
1066 There's more documentation, examples, and a information on our mailing lists
1067 at the Maypole web site:
1069 L<http://maypole.perl.org/>
1071 L<Maypole::Application>, L<Apache::MVC>, L<CGI::Maypole>.
1075 Maypole is currently maintained by Aaron Trevena
1077 =head1 AUTHOR EMERITUS
1079 Simon Cozens, C<simon#cpan.org>
1081 Sebastian Riedel, C<sri#oook.de> maintained Maypole from 1.99_01 to 2.04
1085 Sebastian Riedel, Danijel Milicevic, Dave Slack, Jesse Sheidlower, Jody Belka,
1086 Marcus Ramberg, Mickael Joanne, Randal Schwartz, Simon Flack, Steve Simms,
1087 Veljko Vidovic and all the others who've helped.
1091 You may distribute this code under the same terms as Perl itself.