5 Catalyst::Manual::Tutorial::AdvancedCRUD::FormFu - Catalyst Tutorial - Part 9: Advanced CRUD - FormFu
8 NOTE: This part of the tutorial is in progress and will be ready soon.
12 This is B<Part 9 of 10> for the Catalyst tutorial.
14 L<Tutorial Overview|Catalyst::Manual::Tutorial>
20 L<Introduction|Catalyst::Manual::Tutorial::Intro>
24 L<Catalyst Basics|Catalyst::Manual::Tutorial::CatalystBasics>
28 L<More Catalyst Basics|Catalyst::Manual::Tutorial::MoreCatalystBasics>
32 L<Basic CRUD|Catalyst::Manual::Tutorial::BasicCRUD>
36 L<Authentication|Catalyst::Manual::Tutorial::Authentication>
40 L<Authorization|Catalyst::Manual::Tutorial::Authorization>
44 L<Debugging|Catalyst::Manual::Tutorial::Debugging>
48 L<Testing|Catalyst::Manual::Tutorial::Testing>
52 B<Advanced CRUD::FormFu>
56 L<Appendices|Catalyst::Manual::Tutorial::Appendices>
63 This portion of the tutorial explores L<HTML::FormFu|HTML::FormFu> and
64 how it can be used to manage forms, perform validation of form input,
65 as well as save and restore data to/from the database.
68 L<Catalyst::Manual::Tutorial::AdvancedCRUD|Catalyst::Manual::Tutorial::AdvancedCRUD>
69 for additional form management options other than
70 L<HTML::FormFu|HTML::FormFu>.
73 =head1 Install C<HTML::FormFu>
75 If you are following along in Ubuntu, it turns out that C<HTML::FormFu>
76 is not yet available as a package at the time this was written. To
77 install it with a combination of C<apt-get> packages and traditional
78 CPAN modules, first use C<apt-get> to install most of the modules
79 required by C<HTML::FormFu>:
81 sudo apt-get install libtest-nowarnings-perl libdatetime-format-builder-perl \
82 libdatetime-format-strptime-perl libdatetime-locale-perl \
83 libhtml-tokeparser-simple-perl liblist-moreutils-perl \
84 libregexp-copy-perl libregexp-common-perl libyaml-syck-perl libparams-util-perl
86 Then use the following command to install directly from CPAN the modules
87 that aren't available as Ubuntu/Debian packages via C<apt-get>:
89 sudo cpan File::ShareDir Task::Weaken Config::Any HTML::FormFu \
90 Catalyst::Controller::HTML::FormFu
93 =head1 C<HTML::FormFu> FORM CREATION
95 This section looks at how L<HTML::FormFu|HTML::FormFu> can be used to
96 add additional functionality to the manually created form from Part 4.
99 =head2 Inherit From C<Catalyst::Controller::HTML::FormFu>
101 First, change your C<lib/MyApp/Controller/Books.pm> to inherit from
102 L<Catalyst::Controller::HTML::FormFu|Catalyst::Controller::HTML::FormFu>
103 by changing the C<use base> line from the default of:
105 use base 'Catalyst::Controller';
107 to use the FormFu base controller class:
109 use base 'Catalyst::Controller::HTML::FormFu';
112 =head2 Add Action to Display and Save the Form
114 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
119 Use HTML::FormFu to create a new book
123 sub formfu_create :Local :FormConfig {
126 # Get the form that the :FormConfig attribute saved in the stash
127 my $form = $c->stash->{form};
129 # Check if the form has been submitted (vs. displaying the initial
130 # form) and if the data passed validation. "submitted_and_valid"
131 # is shorthand for "$form->submitted && !$form->has_errors"
132 if ($form->submitted_and_valid) {
134 my $book = $c->model('DB::Books')->new_result({});
135 # Save the form data for the book
136 $form->save_to_model($book);
137 # Set a status message for the user
138 $c->flash->{status_msg} = 'Book created';
139 # Return to the books list
140 $c->response->redirect($c->uri_for('list'));
143 # Get the authors from the DB
144 my @authorObjs = $c->model("DB::Authors")->all();
145 # Create an array of arrayrefs where each arrayref is an author
147 foreach (sort {$a->last_name cmp $b->last_name} @authorObjs) {
148 push(@authors, [$_->id, $_->last_name]);
150 # Get the select added by the config file
151 my $select = $form->get_element({type => 'Select'});
152 # Add the authors to it
153 $select->options(\@authors);
157 $c->stash->{template} = 'books/formfu_create.tt2';
161 =head2 Create a Form Config File
163 Although C<HTML::FormFu> supports any configuration file handled by
164 L<Config::Any|Config::Any>, most people tend to use YAML. First
165 create a directory to hold your form configuration files:
167 mkdir -p root/forms/books
169 Then create the file C<root/forms/books/formfu_create.yml> and enter the
173 # indicator is the field that is used to test for form submission
175 # Start listing the form elements
177 # The first element will be a text field for the title
181 # This is an optional 'mouse over' title pop-up
183 title: Enter a book title here
185 # Another text field for the numeric rating
190 title: Enter a rating between 1 and 5 here
192 # Add a drop-down list for the author selection. Note that we will
193 # dynamically fill in all the authors from the controller but we
194 # could manually set items in the drop-list by adding this YAML code:
196 # - [ '1', 'Bastien' ]
197 # - [ '2', 'Nasseh' ]
207 B<NOTE:> Copying and pasting YAML from perl documentation is sometimes
208 tricky. See the L<Config::General Config for this tutorial> section of
209 this document for a more foolproof config format.
212 =head2 Update the CSS
214 Edit C<root/src/ttsite.css> and add the following lines to the bottom of
228 These changes will display form elements vertically. Note that the
229 existing definition of the C<.error> class is pulling the color scheme
230 settings from the C<root/lib/config/col> file that was created by the
231 TTSite helper. This allows control over the CSS color settings from a
235 =head2 Create a Template Page To Display The Form
237 Open C<root/src/books/formfu_create.tt2> in your editor and enter the following:
239 [% META title = 'Create/Update Book' %]
241 [%# Render the HTML::FormFu Form %]
244 <p><a href="[% c.uri_for('list') %]">Return to book list</a></p>
247 =head2 Add Links for Create and Update via C<HTML::FormFu>
249 Open C<root/src/books/list.tt2> in your editor and add the following to
250 the bottom of the existing file:
254 <a href="[% c.uri_for('formfu_create') %]">Create</a>
257 This adds a new link to the bottom of the book list page that we can
258 use to easily launch our HTML::FormFu-based form.
261 =head2 Test The <HTML::FormFu> Create Form
263 Press C<Ctrl-C> to kill the previous server instance (if it's still
264 running) and restart it:
266 $ script/myapp_server.pl
268 Login as C<test01> (password: mypass). Once at the Book List page,
269 click the new HTML::FormFu "Create" link at the bottom to display the
270 form. Fill in the following values: Title = "Internetworking with
271 TCP/IP Vol. II", Rating = "4", and Author = "Comer". Click Submit,
272 and you will be returned to the Book List page with a "Book created"
273 status message displayed.
275 Also note that this implementation allows you to can create books with
276 bogus information. Although we have constrained the authors with the
277 drop-down list (note that this isn't bulletproof because we still have
278 not prevented a user from "hacking" the form to specify other values),
279 there are no restrictions on items such as the length of the title (for
280 example, you can create a one-letter title) and value for the rating
281 (you can use any number you want, and even non-numeric values with
282 SQLite). The next section will address this concern.
284 B<Note:> Depending on the database you are using and how you established
285 the columns in your tables, the database could obviously provide various
286 levels of "type enforcement" on your data. The key point being made in
287 the previous paragraph is that the I<web application> itself is not
288 performing any validation.
291 =head1 C<HTML::FormFu> VALIDATION AND FILTERING
293 Although the use of L<HTML::FormFu|HTML::FormFu> in the previous section
294 did provide an automated mechanism to build the form, the real power of
295 this module stems from functionality that can automatically validate and
296 filter the user input. Validation uses constraints to be sure that
297 users input appropriate data (for example, that the email field of a
298 form contains a valid email address). Filtering can also be used to
299 remove extraneous whitespace from fields or to escape meta-characters in
303 =head2 Add Constraints
305 Open C<root/forms/books/formfu_create.yml> in your editor and update it
309 # indicator is the field that is used to test for form submission
311 # Start listing the form elements
313 # The first element will be a text field for the title
317 # This is an optional 'mouse over' title pop-up
319 title: Enter a book title here
320 # Add constraints for the field
322 # Force the length to be between 5 and 40 chars
326 # Override the default of 'Invalid input'
327 message: Length must be between 5 and 40 characters
329 # Another text field for the numeric rating
334 title: Enter a rating between 1 and 5 here
335 # Use Filter to clean up the input data
337 # Remove everything except digits
339 # Add constraints to the field
342 # Make sure it's a number
344 message: "Digits only, please."
345 # Filters apply before constraints.
346 # If a user gives the rating "excellent", the NonNumeric filter would remove the entire string as it contains no digits.
347 # Remove the NonNumeric filter and let the Integer constraint handle the validation and error message.
349 # Add a select list for the author selection. Note that we will
350 # dynamically fill in all the authors from the controller but we
351 # could manually set items in the select by adding this YAML code:
353 # - [ '1', 'Bastien' ]
354 # - [ '2', 'Nasseh' ]
358 # Convert the drop-down to a multi-select list
360 # Display 3 entries (user can scroll to see others)
362 # One could argue we don't need to do filters or constraints for
363 # a select list, but it's smart to do validation and sanity
364 # checks on this data in case a user "hacks" the input
365 # Add constraints to the field
367 # Make sure it's a number
375 # Global filters and constraints.
377 # The user cannot leave any fields blank
379 # If not all fields are required, move the Required constraint to the fields that are.
381 # Remove whitespace at both ends
383 # Escape HTML characters for safety
386 B<NOTE:> Copying and pasting YAML from perl documentation is sometimes
387 tricky. See the L<Config::General Config for this tutorial> section of
388 this document for a more foolproof config format.
390 The main changes are:
396 The C<Select> element for C<authors> is changed from a single-select
397 drop-down to a multi-select list by adding configuration for the
398 C<multiple> and C<size> options in C<formfu_create.yml>.
402 Constraints are added to provide validation of the user input. See
403 L<HTML::FormFu::Constraint|HTML::FormFu::Constraint> for other
404 constraints that are available.
408 A variety of filters are run on every field to remove and escape
409 unwanted input. See L<HTML::FormFu::Filter|HTML::FormFu::Filter>
410 for more filter options.
415 =head2 Try Out the Updated Form
417 Press C<Ctrl-C> to kill the previous server instance (if it's still
418 running) and restart it:
420 $ script/myapp_server.pl
422 Make sure you are still logged in as C<test01> and try adding a book
423 with various errors: title less than 5 characters, non-numeric rating, a
424 rating of 0 or 6, etc. Also try selecting one, two, and zero authors.
425 When you click Submit, the HTML::FormFu C<constraint> items will
426 validate the logic and insert feedback as appropriate. Try adding blank
427 spaces at the front or the back of the title and note that it will be
431 =head1 CREATE AND UPDATE/EDIT ACTION
433 Let's expand the work done above to add an edit action. First, open
434 C<lib/MyApp/Controller/Books.pm> and add the following method to the
439 Use HTML::FormFu to update an existing book
443 sub formfu_edit :Local :FormConfig('books/formfu_create.yml') {
444 my ($self, $c, $id) = @_;
446 # Get the specified book
447 my $book = $c->model('DB::Books')->find($id);
449 # Make sure we were able to get a book
451 $c->flash->{error_msg} = "Invalid book -- Cannot edit";
452 $c->response->redirect($c->uri_for('list'));
456 # Get the form that the :FormConfig attribute saved in the stash
457 my $form = $c->stash->{form};
459 # Check if the form has been submitted (vs. displaying the initial
460 # form) and if the data passed validation. "submitted_and_valid"
461 # is shorthand for "$form->submitted && !$form->has_errors"
462 if ($form->submitted_and_valid) {
463 # Save the form data for the book
464 $form->save_to_model($book);
465 # Set a status message for the user
466 $c->flash->{status_msg} = 'Book edited';
467 # Return to the books list
468 $c->response->redirect($c->uri_for('list'));
471 # Get the authors from the DB
472 my @authorObjs = $c->model("DB::Authors")->all();
473 # Create an array of arrayrefs where each arrayref is an author
475 foreach (sort {$a->last_name cmp $b->last_name} @authorObjs) {
476 push(@authors, [$_->id, $_->last_name]);
478 # Get the select added by the config file
479 my $select = $form->get_element({type => 'Select'});
480 # Add the authors to it
481 $select->options(\@authors);
482 # Populate the form with existing values from DB
483 $form->defaults_from_model($book);
487 $c->stash->{template} = 'books/formfu_create.tt2';
490 Most of this code should look familiar to what we used in the
491 C<formfu_create> method (in fact, we should probably centralize some of
492 the common code in separate methods). The main differences are:
498 We accept C<$id> as an argument via the URL.
502 We use C<$id> to look up the existing book from the database.
506 We make sure the C<$id> and book lookup returned a valid book. If not,
507 we set the error message and return to the book list.
511 If the form has been submitted and passes validation, we skip creating a
512 new book and just use C<$form-E<gt>save_to_model> to update the existing
517 If the form is being displayed for the first time (or has failed
518 validation and it being redisplayed), we use
519 C<$form-E<gt>default_from_model> to populate the form with data from the
524 Then, edit C<root/src/books/list.tt2> and add a new link below the
525 existing "Delete" link that allows us to edit/update each existing book.
526 The last E<lt>tdE<gt> cell in the book list table should look like the
530 [% # Add a link to delete a book %]
531 <a href="[% c.uri_for('delete', book.id) %]">Delete</a>
532 [% # Add a link to edit a book %]
533 <a href="[% c.uri_for('formfu_edit', book.id) %]">Edit</a>
537 =head2 Try Out the Edit/Update Feature
539 Press C<Ctrl-C> to kill the previous server instance (if it's still
540 running) and restart it:
542 $ script/myapp_server.pl
544 Make sure you are still logged in as C<test01> and go to the
545 L<http://localhost:3000/books/list> URL in your browser. Click the
546 "Edit" link next to "Internetworking with TCP/IP Vol. II", change the
547 rating to a 3, the "II" at end of the title to the number "2", add
548 Stevens as a co-author (control-click), and click Submit. You will then
549 be returned to the book list with a "Book edited" message at the top in
550 green. Experiment with other edits to various books.
553 =head2 Config::General Config for this tutorial
555 If you are having difficulty with YAML config above, please save the
556 below into the file C<formfu_create.conf> and delete the
557 C<formfu_create.yml> file. The below is in
558 L<Config::General|Config::General> format which follows the syntax of
567 message Length must be between 5 and 40 characters
575 title Enter a book title here
586 title Enter a rating between 1 and 5 here
610 Kennedy Clark, C<hkclark@gmail.com>
612 Please report any errors, issues or suggestions to the author. The
613 most recent version of the Catalyst Tutorial can be found at
614 L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Manual/lib/Catalyst/Manual/Tutorial/>.
616 Copyright 20066-2008, Kennedy Clark, under Creative Commons License
617 (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).