3 Catalyst::Manual::Tutorial::09_AdvancedCRUD::09_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::01_Intro>
20 L<Catalyst Basics|Catalyst::Manual::Tutorial::02_CatalystBasics>
24 L<More Catalyst Basics|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>
28 L<Basic CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD>
32 L<Authentication|Catalyst::Manual::Tutorial::05_Authentication>
36 L<Authorization|Catalyst::Manual::Tutorial::06_Authorization>
40 L<Debugging|Catalyst::Manual::Tutorial::07_Debugging>
44 L<Testing|Catalyst::Manual::Tutorial::08_Testing>
48 B<09_Advanced CRUD::09_FormFu>
52 L<Appendices|Catalyst::Manual::Tutorial::10_Appendices>
59 This portion of the tutorial explores L<HTML::FormFu> and how it can be
60 used to manage forms, perform validation of form input, as well as save
61 and restore data to/from the database. This was written using
62 HTML::FormFu version 0.05001.
64 See L<Catalyst::Manual::Tutorial::09_AdvancedCRUD> for additional form
65 management options other than L<HTML::FormFu>.
68 =head1 HTML::FormFu FORM CREATION
70 This section looks at how L<HTML::FormFu> can be used to add additional
71 functionality to the manually created form from Chapter 4.
74 =head2 Inherit From Catalyst::Controller::HTML::FormFu
76 First, change your C<lib/MyApp/Controller/Books.pm> to inherit from
77 L<Catalyst::Controller::HTML::FormFu> by changing the C<extends> line
80 BEGIN {extends 'Catalyst::Controller'; }
82 to use the FormFu base controller class:
84 BEGIN {extends 'Catalyst::Controller::HTML::FormFu'; }
88 requires 'Catalyst::Controller::HTML::FormFu';
90 to your C<Makefile.PL>.
92 =head2 Add Action to Display and Save the Form
94 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
99 Use HTML::FormFu to create a new book
103 sub formfu_create :Chained('base') :PathPart('formfu_create') :Args(0) :FormConfig {
106 # Get the form that the :FormConfig attribute saved in the stash
107 my $form = $c->stash->{form};
109 # Check if the form has been submitted (vs. displaying the initial
110 # form) and if the data passed validation. "submitted_and_valid"
111 # is shorthand for "$form->submitted && !$form->has_errors"
112 if ($form->submitted_and_valid) {
114 my $book = $c->model('DB::Book')->new_result({});
115 # Save the form data for the book
116 $form->model->update($book);
117 # Set a status message for the user
118 $c->flash->{status_msg} = 'Book created';
119 # Return to the books list
120 $c->response->redirect($c->uri_for($self->action_for('list')));
123 # Get the authors from the DB
124 my @author_objs = $c->model("DB::Author")->all();
125 # Create an array of arrayrefs where each arrayref is an author
127 foreach (sort {$a->last_name cmp $b->last_name} @author_objs) {
128 push(@authors, [$_->id, $_->last_name]);
130 # Get the select added by the config file
131 my $select = $form->get_element({type => 'Select'});
132 # Add the authors to it
133 $select->options(\@authors);
137 $c->stash(template => 'books/formfu_create.tt2');
141 =head2 Create a Form Config File
143 Although C<HTML::FormFu> supports any configuration file handled by
144 L<Config::Any>, most people tend to use YAML. First create a directory
145 to hold your form configuration files:
147 mkdir -p root/forms/books
149 Then create the file C<root/forms/books/formfu_create.yml> and enter the
153 # indicator is the field that is used to test for form submission
155 # Start listing the form elements
157 # The first element will be a text field for the title
161 # This is an optional 'mouse over' title pop-up
163 title: Enter a book title here
165 # Another text field for the numeric rating
170 title: Enter a rating between 1 and 5 here
172 # Add a drop-down list for the author selection. Note that we will
173 # dynamically fill in all the authors from the controller but we
174 # could manually set items in the drop-list by adding this YAML code:
176 # - [ '1', 'Bastien' ]
177 # - [ '2', 'Nasseh' ]
187 B<NOTE:> Copying and pasting YAML from Perl documentation is sometimes
188 tricky. See the L<Config::General Config for this tutorial> section of
189 this document for a more foolproof config format.
192 =head2 Update the CSS
194 Edit C<root/static/css/main.css> and add the following lines to the
209 These changes will display form elements vertically.
212 =head2 Create a Template Page To Display The Form
214 Open C<root/src/books/formfu_create.tt2> in your editor and enter the
217 [% META title = 'Create/Update Book' %]
219 [%# Render the HTML::FormFu Form %]
222 <p><a href="[% c.uri_for(c.controller.action_for('list'))
223 %]">Return to book list</a></p>
226 =head2 Add Links for Create and Update via C<HTML::FormFu>
228 Open C<root/src/books/list.tt2> in your editor and add the following to
229 the bottom of the existing file:
234 <a href="[% c.uri_for(c.controller.action_for('formfu_create')) %]">Create</a>
237 This adds a new link to the bottom of the book list page that we can use
238 to easily launch our HTML::FormFu-based form.
241 =head2 Test The HTML::FormFu Create Form
243 Make sure the server is running with the "-r" restart option:
245 $ script/myapp_server.pl -r
247 Login as C<test01> (password: mypass). Once at the Book List page,
248 click the new HTML::FormFu "Create" link at the bottom to display the
249 form. Fill in the following values:
251 Title: Internetworking with TCP/IP Vol. II
255 Click the Submit button, and you will be returned to the Book List page
256 with a "Book created" status message displayed.
258 Also note that this implementation allows you to create books with any
259 bogus information. Although we have constrained the authors with the
260 drop-down list (note that this isn't bulletproof because we still have
261 not prevented a user from "hacking" the form to specify other values),
262 there are no restrictions on items such as the length of the title (for
263 example, you can create a one-letter title) and the value of the rating
264 (you can use any number you want, and even non-numeric values with
265 SQLite). The next section will address this concern.
267 B<Note:> Depending on the database you are using and how you established
268 the columns in your tables, the database could obviously provide various
269 levels of "type enforcement" on your data. The key point being made in
270 the previous paragraph is that the I<web application> itself is not
271 performing any validation.
274 =head1 HTML::FormFu VALIDATION AND FILTERING
276 Although the use of L<HTML::FormFu> in the previous section did provide
277 an automated mechanism to build the form, the real power of this module
278 stems from functionality that can automatically validate and filter the
279 user input. Validation uses constraints to be sure that users input
280 appropriate data (for example, that the email field of a form contains a
281 valid email address). Filtering can also be used to remove extraneous
282 whitespace from fields or to escape meta-characters in user input.
285 =head2 Add Constraints
287 Open C<root/forms/books/formfu_create.yml> in your editor and update it
291 # indicator is the field that is used to test for form submission
293 # Start listing the form elements
295 # The first element will be a text field for the title
299 # This is an optional 'mouse over' title pop-up
301 title: Enter a book title here
302 # Add constraints for the field
304 # Force the length to be between 5 and 40 chars
308 # Override the default of 'Invalid input'
309 message: Length must be between 5 and 40 characters
311 # Another text field for the numeric rating
316 title: Enter a rating between 1 and 5 here
317 # Use Filter to clean up the input data
318 # Could use 'NonNumeric' below, but since Filters apply *before*
319 # constraints, it would conflict with the 'Integer' constraint below.
320 # So let's skip this and just use the constraint.
322 # Remove everything except digits
324 # Add constraints to the field
326 # Make sure it's a number
328 message: "Required. Digits only, please."
329 # Check the min & max values
333 message: "Must be between 1 and 5."
335 # Add a select list for the author selection. Note that we will
336 # dynamically fill in all the authors from the controller but we
337 # could manually set items in the select by adding this YAML code:
339 # - [ '1', 'Bastien' ]
340 # - [ '2', 'Nasseh' ]
344 # Convert the drop-down to a multi-select list
346 # Display 3 entries (user can scroll to see others)
348 # One could argue we don't need to do filters or constraints for
349 # a select list, but it's smart to do validation and sanity
350 # checks on this data in case a user "hacks" the input
351 # Add constraints to the field
353 # Make sure it's a number
361 # Global filters and constraints.
363 # The user cannot leave any fields blank
365 # If not all fields are required, move the Required constraint to the
368 # Remove whitespace at both ends
370 # Escape HTML characters for safety
373 B<NOTE:> Copying and pasting YAML from Perl documentation is sometimes
374 tricky. See the L<Config::General Config for this tutorial> section of
375 this document for a more foolproof config format.
377 The main changes are:
383 The C<Select> element for C<authors> is changed from a single-select
384 drop-down to a multi-select list by adding configuration for the
385 C<multiple> and C<size> options in C<formfu_create.yml>.
389 Constraints are added to provide validation of the user input. See
390 L<HTML::FormFu::Constraint> for other constraints that are available.
394 A variety of filters are run on every field to remove and escape
395 unwanted input. See L<HTML::FormFu::Filter> for more filter options.
400 =head2 Try Out the Updated Form
402 Make sure you are still logged in as C<test01> and try adding a book
403 with various errors: title less than 5 characters, non-numeric rating, a
404 rating of 0 or 6, etc. Also try selecting one, two, and zero authors.
405 When you click Submit, the HTML::FormFu C<constraint> items will
406 validate the logic and insert feedback as appropriate. Try adding blank
407 spaces at the front or the back of the title and note that it will be
411 =head1 CREATE AND UPDATE/EDIT ACTION
413 Let's expand the work done above to add an edit action. First, open
414 C<lib/MyApp/Controller/Books.pm> and add the following method to the
419 Use HTML::FormFu to update an existing book
423 sub formfu_edit :Chained('object') :PathPart('formfu_edit') :Args(0)
424 :FormConfig('books/formfu_create.yml') {
427 # Get the specified book already saved by the 'object' method
428 my $book = $c->stash->{object};
430 # Make sure we were able to get a book
432 $c->flash->{error_msg} = "Invalid book -- Cannot edit";
433 $c->response->redirect($c->uri_for($self->action_for('list')));
437 # Get the form that the :FormConfig attribute saved in the stash
438 my $form = $c->stash->{form};
440 # Check if the form has been submitted (vs. displaying the initial
441 # form) and if the data passed validation. "submitted_and_valid"
442 # is shorthand for "$form->submitted && !$form->has_errors"
443 if ($form->submitted_and_valid) {
444 # Save the form data for the book
445 $form->model->update($book);
446 # Set a status message for the user
447 $c->flash->{status_msg} = 'Book edited';
448 # Return to the books list
449 $c->response->redirect($c->uri_for($self->action_for('list')));
452 # Get the authors from the DB
453 my @author_objs = $c->model("DB::Author")->all();
454 # Create an array of arrayrefs where each arrayref is an author
456 foreach (sort {$a->last_name cmp $b->last_name} @author_objs) {
457 push(@authors, [$_->id, $_->last_name]);
459 # Get the select added by the config file
460 my $select = $form->get_element({type => 'Select'});
461 # Add the authors to it
462 $select->options(\@authors);
463 # Populate the form with existing values from DB
464 $form->model->default_values($book);
468 $c->stash(template => 'books/formfu_create.tt2');
471 Most of this code should look familiar to what we used in the
472 C<formfu_create> method (in fact, we should probably centralize some of
473 the common code in separate methods). The main differences are:
479 We have to manually specify the name of the FormFu .yml file as an
480 argument to C<:FormConfig> because the name can no longer be
481 automatically deduced from the name of our action/method (by default,
482 FormFu would look for a file named C<books/formfu_edit.yml>).
486 We load the book object from the stash (found using the $id passed to
487 the Chained object method)
491 We use C<$id> to look up the existing book from the database.
495 We make sure the book lookup returned a valid book. If not, we set the
496 error message and return to the book list.
500 If the form has been submitted and passes validation, we skip creating a
501 new book and just use C<$form-E<gt>model-E<gt>update> to update the
506 If the form is being displayed for the first time (or has failed
507 validation and it being redisplayed), we use
508 C<$form-E<gt>model-E<gt>default_values> to populate the form with data
513 Then, edit C<root/src/books/list.tt2> and add a new link below the
514 existing "Delete" link that allows us to edit/update each existing book.
515 The last E<lt>tdE<gt> cell in the book list table should look like the
520 [% # Add a link to delete a book %]
521 <a href="[% c.uri_for(c.controller.action_for('delete'), [book.id]) %]">Delete</a>
522 [% # Add a link to edit a book %]
523 <a href="[% c.uri_for(c.controller.action_for('formfu_edit'), [book.id]) %]">Edit</a>
527 B<Note:> Only add two lines (the "Add a link to edit a book" comment and
528 the href for C<formfu_edit>). Make sure you add it below the existing
532 =head2 Try Out the Edit/Update Feature
534 Make sure you are still logged in as C<test01> and go to the
535 L<http://localhost:3000/books/list> URL in your browser. Click the
536 "Edit" link next to "Internetworking with TCP/IP Vol. II", change the
537 rating to a 3, the "II" at end of the title to the number "2", add
538 Stevens as a co-author (control-click), and click Submit. You will then
539 be returned to the book list with a "Book edited" message at the top in
540 green. Experiment with other edits to various books.
543 =head2 More Things to Try
545 You are now armed with enough knowledge to be dangerous. You can keep
546 tweaking the example application; some things you might want to do:
552 Add an appropriate authorization check to the new Edit function.
556 Cleanup the List page so that the Login link only displays when the user
557 isn't logged in and the Logout link only displays when a user is logged
562 Add a more sensible policy for when and how users and admins can do
563 things in the CRUD cycle.
567 Support the CRUD cycle for authors.
571 Or you can proceed to write your own application, which is probably the
572 real reason you worked through this Tutorial in the first place.
575 =head2 Config::General Config for this tutorial
577 If you are having difficulty with YAML config above, please save the
578 below into the file C<formfu_create.conf> and delete the
579 C<formfu_create.yml> file. The below is in L<Config::General> format
580 which follows the syntax of Apache config files.
588 message Length must be between 5 and 40 characters
596 title Enter a book title here
607 title Enter a rating between 1 and 5 here
630 Kennedy Clark, C<hkclark@gmail.com>
632 Feel free to contact the author for any errors or suggestions, but the
633 best way to report issues is via the CPAN RT Bug system at
634 <https://rt.cpan.org/Public/Dist/Display.html?Name=Catalyst-Manual>.
636 The most recent version of the Catalyst Tutorial can be found at
637 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
639 Copyright 2006-2010, Kennedy Clark, under the
640 Creative Commons Attribution Share-Alike License Version 3.0
641 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).