3 Catalyst::Manual::Tutorial::AdvancedCRUD::FormFu - Catalyst Tutorial - Chapter 9: Advanced CRUD - FormFu
8 This is B<Chapter 9 of 10> for the Catalyst tutorial.
10 L<Tutorial Overview|Catalyst::Manual::Tutorial>
16 L<Introduction|Catalyst::Manual::Tutorial::Intro>
20 L<Catalyst Basics|Catalyst::Manual::Tutorial::CatalystBasics>
24 L<More Catalyst Basics|Catalyst::Manual::Tutorial::MoreCatalystBasics>
28 L<Basic CRUD|Catalyst::Manual::Tutorial::BasicCRUD>
32 L<Authentication|Catalyst::Manual::Tutorial::Authentication>
36 L<Authorization|Catalyst::Manual::Tutorial::Authorization>
40 L<Debugging|Catalyst::Manual::Tutorial::Debugging>
44 L<Testing|Catalyst::Manual::Tutorial::Testing>
48 B<Advanced CRUD::FormFu>
52 L<Appendices|Catalyst::Manual::Tutorial::Appendices>
59 This portion of the tutorial explores L<HTML::FormFu|HTML::FormFu> and
60 how it can be used to manage forms, perform validation of form input,
61 as well as save and restore data to/from the database. This was written
62 using HTML::FormFu version 0.03007.
65 L<Catalyst::Manual::Tutorial::AdvancedCRUD|Catalyst::Manual::Tutorial::AdvancedCRUD>
66 for additional form management options other than
67 L<HTML::FormFu|HTML::FormFu>.
70 =head1 Install C<HTML::FormFu>
72 If you are following along in Debian 5, it turns out that some of the
73 modules we need are not yet available as Debian packages at the time
74 this was written. To install it with a combination of Debian packages
75 and traditional CPAN modules, first use C<aptitude> to install most of
78 we need to install the
79 L<HTML::FormFu|HTML::FormFu> package:
81 sudo aptitude -y install libhtml-formfu-perl libmoose-perl \
82 libregexp-assemble-perl libhtml-formfu-model-dbic-perl
88 Then use the following command to install directly from CPAN the modules
89 that aren't available as Debian packages:
91 sudo cpan Catalyst::Component::InstancePerContext Catalyst::Controller::HTML::FormFu
94 =head1 C<HTML::FormFu> FORM CREATION
96 This section looks at how L<HTML::FormFu|HTML::FormFu> can be used to
97 add additional functionality to the manually created form from Chapter 4.
100 =head2 Inherit From C<Catalyst::Controller::HTML::FormFu>
102 First, change your C<lib/MyApp/Controller/Books.pm> to inherit from
103 L<Catalyst::Controller::HTML::FormFu|Catalyst::Controller::HTML::FormFu>
104 by changing the C<use parent> line from the default of:
106 use parent 'Catalyst::Controller';
108 to use the FormFu base controller class:
110 use parent 'Catalyst::Controller::HTML::FormFu';
113 =head2 Add Action to Display and Save the Form
115 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
120 Use HTML::FormFu to create a new book
124 sub formfu_create :Chained('base) :PathPart('formfu_create') :Args(0) :FormConfig {
127 # Get the form that the :FormConfig attribute saved in the stash
128 my $form = $c->stash->{form};
130 # Check if the form has been submitted (vs. displaying the initial
131 # form) and if the data passed validation. "submitted_and_valid"
132 # is shorthand for "$form->submitted && !$form->has_errors"
133 if ($form->submitted_and_valid) {
135 my $book = $c->model('DB::Books')->new_result({});
136 # Save the form data for the book
137 $form->model->update($book);
138 # Set a status message for the user
139 $c->flash->{status_msg} = 'Book created';
140 # Return to the books list
141 $c->response->redirect($c->uri_for($self->action_for('list')));
144 # Get the authors from the DB
145 my @author_objs = $c->model("DB::Authors")->all();
146 # Create an array of arrayrefs where each arrayref is an author
148 foreach (sort {$a->last_name cmp $b->last_name} @author_objs) {
149 push(@authors, [$_->id, $_->last_name]);
151 # Get the select added by the config file
152 my $select = $form->get_element({type => 'Select'});
153 # Add the authors to it
154 $select->options(\@authors);
158 $c->stash->{template} = 'books/formfu_create.tt2';
162 =head2 Create a Form Config File
164 Although C<HTML::FormFu> supports any configuration file handled by
165 L<Config::Any|Config::Any>, most people tend to use YAML. First
166 create a directory to hold your form configuration files:
168 mkdir -p root/forms/books
170 Then create the file C<root/forms/books/formfu_create.yml> and enter the
174 # indicator is the field that is used to test for form submission
176 # Start listing the form elements
178 # The first element will be a text field for the title
182 # This is an optional 'mouse over' title pop-up
184 title: Enter a book title here
186 # Another text field for the numeric rating
191 title: Enter a rating between 1 and 5 here
193 # Add a drop-down list for the author selection. Note that we will
194 # dynamically fill in all the authors from the controller but we
195 # could manually set items in the drop-list by adding this YAML code:
197 # - [ '1', 'Bastien' ]
198 # - [ '2', 'Nasseh' ]
208 B<NOTE:> Copying and pasting YAML from perl documentation is sometimes
209 tricky. See the L<Config::General Config for this tutorial> section of
210 this document for a more foolproof config format.
213 =head2 Update the CSS
215 Edit C<root/static/css/main.css> and add the following lines to the bottom of
230 These changes will display form elements vertically. Note that the
231 existing definition of the C<.error> class is pulling the color scheme
232 settings from the C<root/lib/config/col> file that was created by the
233 TTSite helper. This allows control over the CSS color settings from a
237 =head2 Create a Template Page To Display The Form
239 Open C<root/src/books/formfu_create.tt2> in your editor and enter the following:
241 [% META title = 'Create/Update Book' %]
243 [%# Render the HTML::FormFu Form %]
246 <p><a href="[% c.uri_for(c.controller.action_for('list')) %]">Return to book list</a></p>
249 =head2 Add Links for Create and Update via C<HTML::FormFu>
251 Open C<root/src/books/list.tt2> in your editor and add the following to
252 the bottom of the existing file:
257 <a href="[% c.uri_for(c.controller.action_for('formfu_create')) %]">Create</a>
260 This adds a new link to the bottom of the book list page that we can
261 use to easily launch our HTML::FormFu-based form.
264 =head2 Test The <HTML::FormFu> Create Form
266 Press C<Ctrl-C> to kill the previous server instance (if it's still
267 running) and restart it:
269 $ script/myapp_server.pl
271 Login as C<test01> (password: mypass). Once at the Book List page,
272 click the new HTML::FormFu "Create" link at the bottom to display the
273 form. Fill in the following values: Title = "Internetworking with
274 TCP/IP Vol. II", Rating = "4", and Author = "Comer". Click Submit,
275 and you will be returned to the Book List page with a "Book created"
276 status message displayed.
278 Also note that this implementation allows you to can create books with
279 bogus information. Although we have constrained the authors with the
280 drop-down list (note that this isn't bulletproof because we still have
281 not prevented a user from "hacking" the form to specify other values),
282 there are no restrictions on items such as the length of the title (for
283 example, you can create a one-letter title) and value for the rating
284 (you can use any number you want, and even non-numeric values with
285 SQLite). The next section will address this concern.
287 B<Note:> Depending on the database you are using and how you established
288 the columns in your tables, the database could obviously provide various
289 levels of "type enforcement" on your data. The key point being made in
290 the previous paragraph is that the I<web application> itself is not
291 performing any validation.
294 =head1 C<HTML::FormFu> VALIDATION AND FILTERING
296 Although the use of L<HTML::FormFu|HTML::FormFu> in the previous section
297 did provide an automated mechanism to build the form, the real power of
298 this module stems from functionality that can automatically validate and
299 filter the user input. Validation uses constraints to be sure that
300 users input appropriate data (for example, that the email field of a
301 form contains a valid email address). Filtering can also be used to
302 remove extraneous whitespace from fields or to escape meta-characters in
306 =head2 Add Constraints
308 Open C<root/forms/books/formfu_create.yml> in your editor and update it
312 # indicator is the field that is used to test for form submission
314 # Start listing the form elements
316 # The first element will be a text field for the title
320 # This is an optional 'mouse over' title pop-up
322 title: Enter a book title here
323 # Add constraints for the field
325 # Force the length to be between 5 and 40 chars
329 # Override the default of 'Invalid input'
330 message: Length must be between 5 and 40 characters
332 # Another text field for the numeric rating
337 title: Enter a rating between 1 and 5 here
338 # Use Filter to clean up the input data
339 # Could use 'NonNumeric' below, but since Filters apply *before*
340 # constraints, it would conflict with the 'Integer' constraint below.
341 # So let's skip this and just use the constraint.
343 # Remove everything except digits
345 # Add constraints to the field
347 # Make sure it's a number
349 message: "Required. Digits only, please."
350 # Check the min & max values
354 message: "Must be between 1 and 5."
356 # Add a select list for the author selection. Note that we will
357 # dynamically fill in all the authors from the controller but we
358 # could manually set items in the select by adding this YAML code:
360 # - [ '1', 'Bastien' ]
361 # - [ '2', 'Nasseh' ]
365 # Convert the drop-down to a multi-select list
367 # Display 3 entries (user can scroll to see others)
369 # One could argue we don't need to do filters or constraints for
370 # a select list, but it's smart to do validation and sanity
371 # checks on this data in case a user "hacks" the input
372 # Add constraints to the field
374 # Make sure it's a number
382 # Global filters and constraints.
384 # The user cannot leave any fields blank
386 # If not all fields are required, move the Required constraint to the
389 # Remove whitespace at both ends
391 # Escape HTML characters for safety
394 B<NOTE:> Copying and pasting YAML from perl documentation is sometimes
395 tricky. See the L<Config::General Config for this tutorial> section of
396 this document for a more foolproof config format.
398 The main changes are:
404 The C<Select> element for C<authors> is changed from a single-select
405 drop-down to a multi-select list by adding configuration for the
406 C<multiple> and C<size> options in C<formfu_create.yml>.
410 Constraints are added to provide validation of the user input. See
411 L<HTML::FormFu::Constraint|HTML::FormFu::Constraint> for other
412 constraints that are available.
416 A variety of filters are run on every field to remove and escape
417 unwanted input. See L<HTML::FormFu::Filter|HTML::FormFu::Filter>
418 for more filter options.
423 =head2 Try Out the Updated Form
425 Press C<Ctrl-C> to kill the previous server instance (if it's still
426 running) and restart it:
428 $ script/myapp_server.pl
430 Make sure you are still logged in as C<test01> and try adding a book
431 with various errors: title less than 5 characters, non-numeric rating, a
432 rating of 0 or 6, etc. Also try selecting one, two, and zero authors.
433 When you click Submit, the HTML::FormFu C<constraint> items will
434 validate the logic and insert feedback as appropriate. Try adding blank
435 spaces at the front or the back of the title and note that it will be
439 =head1 CREATE AND UPDATE/EDIT ACTION
441 Let's expand the work done above to add an edit action. First, open
442 C<lib/MyApp/Controller/Books.pm> and add the following method to the
447 Use HTML::FormFu to update an existing book
451 sub formfu_edit :Chained('object') :PathPart('formfu_edit') :Args(0)
452 :FormConfig('books/formfu_create.yml') {
453 my ($self, $c, $id) = @_;
455 # Get the specified book
456 my $book = $c->model('DB::Books')->find($id);
458 # Make sure we were able to get a book
460 $c->flash->{error_msg} = "Invalid book -- Cannot edit";
461 $c->response->redirect($c->uri_for($self->action_for('list')));
465 # Get the form that the :FormConfig attribute saved in the stash
466 my $form = $c->stash->{form};
468 # Check if the form has been submitted (vs. displaying the initial
469 # form) and if the data passed validation. "submitted_and_valid"
470 # is shorthand for "$form->submitted && !$form->has_errors"
471 if ($form->submitted_and_valid) {
472 # Save the form data for the book
473 $form->model->update($book);
474 # Set a status message for the user
475 $c->flash->{status_msg} = 'Book edited';
476 # Return to the books list
477 $c->response->redirect($c->uri_for($self->action_for('list')));
480 # Get the authors from the DB
481 my @author_objs = $c->model("DB::Authors")->all();
482 # Create an array of arrayrefs where each arrayref is an author
484 foreach (sort {$a->last_name cmp $b->last_name} @author_bjs) {
485 push(@authors, [$_->id, $_->last_name]);
487 # Get the select added by the config file
488 my $select = $form->get_element({type => 'Select'});
489 # Add the authors to it
490 $select->options(\@authors);
491 # Populate the form with existing values from DB
492 $form->model->default_values($book);
496 $c->stash->{template} = 'books/formfu_create.tt2';
499 Most of this code should look familiar to what we used in the
500 C<formfu_create> method (in fact, we should probably centralize some of
501 the common code in separate methods). The main differences are:
507 We accept C<$id> as an argument via the URL.
511 We use C<$id> to look up the existing book from the database.
515 We make sure the C<$id> and book lookup returned a valid book. If not,
516 we set the error message and return to the book list.
520 If the form has been submitted and passes validation, we skip creating a
521 new book and just use C<$form-E<gt>model-E<gt>update> to update the existing
526 If the form is being displayed for the first time (or has failed
527 validation and it being redisplayed), we use
528 C<$form-E<gt>model-E<gt>default_values> to populate the form with data from the
533 Then, edit C<root/src/books/list.tt2> and add a new link below the
534 existing "Delete" link that allows us to edit/update each existing book.
535 The last E<lt>tdE<gt> cell in the book list table should look like the
540 [% # Add a link to delete a book %]
541 <a href="[% c.uri_for(c.controller.action_for('delete'), [book.id]) %]">Delete</a>
542 [% # Add a link to edit a book %]
543 <a href="[% c.uri_for(c.controller.action_for('formfu_edit'), [book.id]) %]">Edit</a>
547 B<Note:> Only add two lines (the "Add a link to edit a book" comment
548 and the href for C<formfu_edit>). Make sure you add it below the
549 existing C<delete> link.
552 =head2 Try Out the Edit/Update Feature
554 Press C<Ctrl-C> to kill the previous server instance (if it's still
555 running) and restart it:
557 $ script/myapp_server.pl
559 Make sure you are still logged in as C<test01> and go to the
560 L<http://localhost:3000/books/list> URL in your browser. Click the
561 "Edit" link next to "Internetworking with TCP/IP Vol. II", change the
562 rating to a 3, the "II" at end of the title to the number "2", add
563 Stevens as a co-author (control-click), and click Submit. You will then
564 be returned to the book list with a "Book edited" message at the top in
565 green. Experiment with other edits to various books.
567 =head2 More Things to Try
569 You are now armed with enough knowledge to be dangerous. You can keep
570 tweaking the example application; some things you might want to do:
576 Add an appropriate authorization check to the new Edit function.
580 Cleanup the List page so that the Login link only displays when the user
581 isn't logged in and the Logout link only displays when a user is logged
586 Add a more sensible policy for when and how users and admins can do
587 things in the CRUD cycle.
591 Support the CRUD cycle for authors.
595 Or you can proceed to write your own application, which is probably the
596 real reason you worked through this Tutorial in the first place.
598 =head2 Config::General Config for this tutorial
600 If you are having difficulty with YAML config above, please save the
601 below into the file C<formfu_create.conf> and delete the
602 C<formfu_create.yml> file. The below is in
603 L<Config::General|Config::General> format which follows the syntax of
612 message Length must be between 5 and 40 characters
620 title Enter a book title here
631 title Enter a rating between 1 and 5 here
655 Kennedy Clark, C<hkclark@gmail.com>
657 Please report any errors, issues or suggestions to the author. The
658 most recent version of the Catalyst Tutorial can be found at
659 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.70/trunk/lib/Catalyst/Manual/Tutorial/>.
661 Copyright 2006-2008, Kennedy Clark, under Creative Commons License
662 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).