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1 | =head1 NAME |
2 | |
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3 | Catalyst::Manual::Tutorial::AdvancedCRUD - Catalyst Tutorial - Part 8: Advanced CRUD |
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4 | |
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5 | =head1 OVERVIEW |
6 | |
7 | This is B<Part 8 of 9> for the Catalyst tutorial. |
8 | |
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9 | L<Tutorial Overview|Catalyst::Manual::Tutorial> |
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10 | |
11 | =over 4 |
12 | |
13 | =item 1 |
14 | |
15 | L<Introduction|Catalyst::Manual::Tutorial::Intro> |
16 | |
17 | =item 2 |
18 | |
19 | L<Catalyst Basics|Catalyst::Manual::Tutorial::CatalystBasics> |
20 | |
21 | =item 3 |
22 | |
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23 | L<Basic CRUD|Catalyst::Manual::Tutorial_BasicCRUD> |
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24 | |
25 | =item 4 |
26 | |
27 | L<Authentication|Catalyst::Manual::Tutorial::Authentication> |
28 | |
29 | =item 5 |
30 | |
31 | L<Authorization|Catalyst::Manual::Tutorial::Authorization> |
32 | |
33 | =item 6 |
34 | |
35 | L<Debugging|Catalyst::Manual::Tutorial::Debugging> |
36 | |
37 | =item 7 |
38 | |
39 | L<Testing|Catalyst::Manual::Tutorial::Testing> |
40 | |
41 | =item 8 |
42 | |
43 | B<AdvancedCRUD> |
44 | |
45 | =item 9 |
46 | |
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47 | L<Appendices|Catalyst::Manual::Tutorial::Appendices> |
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48 | |
49 | =back |
50 | |
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51 | =head1 DESCRIPTION |
52 | |
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53 | This part of the tutorial explores more advanced functionality for |
54 | Create, Read, Update, and Delete (CRUD) than we saw in Part 3. In |
55 | particular, it looks at a number of techniques that can be useful for |
56 | the Update portion of CRUD, such as automated form generation, |
57 | validation of user-entered data, and automated transfer of data between |
58 | forms and model objects. |
59 | |
60 | In keeping with the Catalyst (and Perl) spirit of flexibility, there are |
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61 | many different ways to approach advanced CRUD operations in a Catalyst |
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62 | environment. One alternative is to use |
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63 | L<Catalyst::Helper::Controller::Scaffold|Catalyst::Helper::Controller::Scaffold> |
64 | to instantly construct a set of Controller methods and templates for |
65 | basic CRUD operations. Although a popular subject in Quicktime |
66 | movies that serve as promotional material for various frameworks, |
67 | real-world applications generally require more control. Other |
68 | options include L<Data::FormValidator|Data::FormValidator> and |
69 | L<HTML::FillInForm|HTML::FillInForm>. |
70 | |
71 | Here, we will make use of the L<HTML::Widget|HTML::Widget> to not only |
72 | ease form creation, but to also provide validation of the submitted |
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73 | data. The approached used by this part of the tutorial is to slowly |
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74 | incorporate additional L<HTML::Widget|HTML::Widget> functionality in a |
75 | step-wise fashion (we start with fairly simple form creation and then |
76 | move on to more complex and "magical" features such as validation and |
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77 | auto-population/auto-saving). |
78 | |
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79 | B<Note:> Part 8 of the tutorial is optional. Users who do not wish to |
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80 | use L<HTML::Widget|HTML::Widget> may skip this part. |
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81 | |
82 | B<TIP>: Note that all of the code for this part of the tutorial can be |
83 | pulled from the Catalyst Subversion repository in one step with the |
84 | following command: |
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85 | |
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86 | svn co http://dev.catalyst.perl.org/repos/Catalyst/tags/examples/Tutorial/MyApp/5.7/AdvancedCRUD MyApp |
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87 | |
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88 | =head1 C<HTML::WIDGET> FORM CREATION |
89 | |
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90 | This section looks at how L<HTML::Widget|HTML::Widget> can be used to |
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91 | add additional functionality to the manually created form from Part 3. |
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92 | |
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93 | =head2 Add the C<HTML::Widget> Plugin |
94 | |
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95 | Open C<lib/MyApp.pm> in your editor and add the following to the list of |
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96 | plugins (be sure to leave the existing plugins enabled): |
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97 | |
98 | HTML::Widget |
99 | |
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100 | =head2 Add a Form Creation Helper Method |
101 | |
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102 | Open C<lib/MyApp/Controller/Books.pm> in your editor and add the |
103 | following method: |
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104 | |
105 | =head2 make_book_widget |
106 | |
107 | Build an HTML::Widget form for book creation and updates |
108 | |
109 | =cut |
110 | |
111 | sub make_book_widget { |
112 | my ($self, $c) = @_; |
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113 | |
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114 | # Create an HTML::Widget to build the form |
115 | my $w = $c->widget('book_form')->method('post'); |
116 | |
117 | # Get authors |
118 | my @authorObjs = $c->model("MyAppDB::Author")->all(); |
119 | my @authors = map {$_->id => $_->last_name } |
120 | sort {$a->last_name cmp $b->last_name} @authorObjs; |
121 | |
122 | # Create the form feilds |
123 | $w->element('Textfield', 'title' )->label('Title')->size(60); |
124 | $w->element('Textfield', 'rating' )->label('Rating')->size(1); |
125 | $w->element('Select', 'authors')->label('Authors') |
126 | ->options(@authors); |
127 | $w->element('Submit', 'submit' )->value('submit'); |
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128 | |
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129 | # Return the widget |
130 | return $w; |
131 | } |
132 | |
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133 | This method provides a central location that builds an |
134 | HTML::Widget-based form with the appropriate fields. The "Get authors" |
135 | code uses DBIC to retrieve a list of model objects and then uses C<map> |
136 | to create a hash where the hash keys are the database primary keys from |
137 | the authors table and the associated values are the last names of the |
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138 | authors. |
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139 | |
140 | =head2 Add Actions to Display and Save the Form |
141 | |
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142 | Open C<lib/MyApp/Controller/Books.pm> in your editor and add the |
143 | following methods: |
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144 | |
145 | =head2 hw_create |
146 | |
147 | Build an HTML::Widget form for book creation and updates |
148 | |
149 | =cut |
150 | |
151 | sub hw_create : Local { |
152 | my ($self, $c) = @_; |
153 | |
154 | # Create the widget and set the action for the form |
155 | my $w = $self->make_book_widget($c); |
156 | $w->action($c->uri_for('hw_create_do')); |
157 | |
158 | # Write form to stash variable for use in template |
159 | $c->stash->{widget_result} = $w->result; |
160 | |
161 | # Set the template |
162 | $c->stash->{template} = 'books/hw_form.tt2'; |
163 | } |
164 | |
165 | |
166 | =head2 hw_create_do |
167 | |
168 | Build an HTML::Widget form for book creation and updates |
169 | |
170 | =cut |
171 | |
172 | sub hw_create_do : Local { |
173 | my ($self, $c) = @_; |
174 | |
175 | # Retrieve the data from the form |
176 | my $title = $c->request->params->{title}; |
177 | my $rating = $c->request->params->{rating}; |
178 | my $authors = $c->request->params->{authors}; |
179 | |
180 | # Call create() on the book model object. Pass the table |
181 | # columns/field values we want to set as hash values |
182 | my $book = $c->model('MyAppDB::Book')->create({ |
183 | title => $title, |
184 | rating => $rating |
185 | }); |
186 | |
187 | # Add a record to the join table for this book, mapping to |
188 | # appropriate author |
189 | $book->add_to_book_authors({author_id => $authors}); |
190 | |
191 | # Set a status message for the user |
192 | $c->stash->{status_msg} = 'Book created'; |
193 | |
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194 | # Use 'hw_create' to redisplay the form. As discussed in |
195 | # Part 3, 'detach' is like 'forward', but it does not return |
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196 | $c->detach('hw_create'); |
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197 | } |
198 | |
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199 | Note how we use C<make_book_widget> to build the core parts of the form |
200 | in one location, but we set the action (the URL the form is sent to when |
201 | the user clicks the 'Submit' button) separately in C<hw_create>. Doing |
202 | so allows us to have the same form submit the data to different actions |
203 | (e.g., C<hw_create_do> for a create operation but C<hw_update_do> to |
204 | update an existing book object). |
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205 | |
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206 | =head2 Update the CSS |
207 | |
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208 | Edit C<root/src/ttsite.css> and add the following lines to the bottom of |
209 | the file: |
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210 | |
211 | label { |
212 | display: block; |
213 | width: 10em; |
214 | position: relative; |
215 | margin: .5em 0em; |
216 | } |
217 | label input { |
218 | position: absolute; |
219 | left: 100%; |
220 | } |
221 | label select { |
222 | position: absolute; |
223 | left: 100%; |
224 | } |
225 | .submit { |
226 | margin-top: 2em;; |
227 | } |
228 | .error_messages { |
229 | color: [% site.col.error %]; |
230 | } |
231 | |
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232 | These changes will display form elements vertically and also show error |
233 | messages in red. Note that we are pulling the color scheme settings |
234 | from the C<root/lib/config/col> file that was created by the TTSite |
235 | helper. This allows us to change the color used by various error styles |
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236 | in the CSS from a single location. |
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237 | |
238 | =head2 Create a Template Page To Display The Form |
239 | |
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240 | Open C<root/src/books/hw_form.tt2> in your editor and enter the following: |
241 | |
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242 | [% META title = 'Create/Update Book' %] |
243 | |
244 | [% widget_result.as_xml %] |
245 | |
246 | <p><a href="[% Catalyst.uri_for('list') %]">Return to book list</a></p> |
247 | |
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248 | =head2 Add Links for Create and Update via C<HTML::Widget> |
249 | |
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250 | Open C<root/src/books/list.tt2> in your editor and add the following to |
251 | the bottom of the existing file: |
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252 | |
253 | <p> |
254 | HTML::Widget: |
255 | <a href="[% Catalyst.uri_for('hw_create') %]">Create</a> |
256 | <a href="[% Catalyst.uri_for('hw_update') %]">Update</a> |
257 | </p> |
258 | |
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259 | =head2 Test The <HTML::Widget> Create Form |
260 | |
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261 | Press C<Ctrl-C> to kill the previous server instance (if it's still |
262 | running) and restart it: |
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263 | |
264 | $ script/myapp_server.pl |
265 | |
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266 | Login as C<test01>. Once at the Book List page, click the HTML::Widget |
267 | "Create" link to display for form produced by C<make_book_widget>. Fill |
268 | out the form with the following values: Title = "Internetworking with |
269 | TCP/IP Vol. II", Rating = "4", and Author = "Comer". Click Submit, and |
270 | you will be returned to the Create/Update Book page with a "Book |
271 | created" status message displayed. Click "Return to book list" to view |
272 | the newly created book on the main list. |
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273 | |
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274 | Also note that this implementation allows you to can create books with |
275 | bogus information. Although we have constrained the authors with the |
276 | drop-down list, there are no restrictions on items such as the length of |
277 | the title (for example, you can create a one-letter title) and value for |
278 | the rating (you can use any number you want, and even non-numeric values |
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279 | with SQLite). The next section will address this concern. |
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280 | |
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281 | B<Note:> Depending on the database you are using and how you established |
282 | the columns in your tables, the database could obviously provide various |
283 | levels of "type enforcement" on your data. The key point being made in |
284 | the previous paragraph is that the I<web application> itself is not |
285 | performing any validation. |
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286 | |
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287 | =head1 C<HTML::WIDGET> VALIDATION AND FILTERING |
288 | |
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289 | Although the use of L<HTML::Widget|HTML::Widget> in the previous section |
290 | did provide an automated mechanism to build the form, the real power of |
291 | this module stems from functionality that can automatically validate and |
292 | filter the user input. Validation uses constraints to be sure that |
293 | users input appropriate data (for example, that the email field of a |
294 | form contains a valid email address). Filtering can be used to remove |
295 | extraneous whitespace from fields or to escape meta-characters in user |
296 | input. |
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297 | |
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298 | =head2 Add Constraints and Filters to the Widget Creation Method |
299 | |
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300 | Open C<lib/MyApp/Controller/Books.pm> in your editor and update the |
301 | C<make_book_widget> method to match the following (new sections have |
302 | been marked with a C<*** NEW:> comment): |
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303 | |
304 | sub make_book_widget { |
305 | my ($self, $c) = @_; |
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306 | |
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307 | # Create an HTML::Widget to build the form |
308 | my $w = $c->widget('book_form')->method('post'); |
309 | |
310 | # Get authors |
311 | my @authorObjs = $c->model("MyAppDB::Author")->all(); |
312 | my @authors = map {$_->id => $_->last_name } |
313 | sort {$a->last_name cmp $b->last_name} @authorObjs; |
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314 | |
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315 | # Create the form feilds |
316 | $w->element('Textfield', 'title' )->label('Title')->size(60); |
317 | $w->element('Textfield', 'rating' )->label('Rating')->size(1); |
318 | # ***NEW: Convert to multi-select list |
319 | $w->element('Select', 'authors')->label('Authors') |
320 | ->options(@authors)->multiple(1)->size(3); |
321 | $w->element('Submit', 'submit' )->value('submit'); |
322 | |
323 | # ***NEW: Set constraints |
324 | $w->constraint(All => qw/title rating authors/) |
325 | ->message('Required. '); |
326 | $w->constraint(Integer => qw/rating/) |
327 | ->message('Must be an integer. '); |
328 | $w->constraint(Range => qw/rating/)->min(1)->max(5) |
329 | ->message('Must be a number between 1 and 5. '); |
330 | $w->constraint(Length => qw/title/)->min(5)->max(50) |
331 | ->message('Must be between 5 and 50 characters. '); |
332 | |
333 | # ***NEW: Set filters |
334 | for my $column (qw/title rating authors/) { |
335 | $w->filter( HTMLEscape => $column ); |
336 | $w->filter( TrimEdges => $column ); |
337 | } |
338 | |
339 | # Return the widget |
340 | return $w; |
341 | } |
342 | |
343 | The main changes are: |
344 | |
345 | =over 4 |
346 | |
347 | =item * |
348 | |
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349 | The C<Select> element for C<authors> is changed from a single-select |
350 | drop-down to a multi-select list by adding calls to C<multiple> (set to |
351 | C<true>) and C<size> (set to the number of rows to display). |
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352 | |
353 | =item * |
354 | |
355 | Four sets of constraints are added to provide validation of the user input. |
356 | |
357 | =item * |
358 | |
359 | Two filters are run on every field to remove and escape unwanted input. |
360 | |
361 | =back |
362 | |
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363 | =head2 Rebuild the Form Submission Method to Include Validation |
364 | |
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365 | Edit C<lib/MyApp/Controller/Books.pm> and change C<hw_create_do> to |
366 | match the following code (enough of the code is different that you |
367 | probably want to cut and paste this over code the existing method): |
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368 | |
369 | sub hw_create_do : Local { |
370 | my ($self, $c) = @_; |
371 | |
372 | # Retrieve the data from the form |
373 | my $title = $c->request->params->{title}; |
374 | my $rating = $c->request->params->{rating}; |
375 | my $authors = $c->request->params->{authors}; |
376 | |
377 | # Create the widget and set the action for the form |
378 | my $w = $self->make_book_widget($c); |
379 | $w->action($c->uri_for('hw_create_do')); |
380 | |
381 | # Validate the form parameters |
382 | my $result = $w->process($c->req); |
383 | |
384 | # Write form (including validation error messages) to |
385 | # stash variable for use in template |
386 | $c->stash->{widget_result} = $result; |
387 | |
388 | # Were their validation errors? |
389 | if ($result->has_errors) { |
390 | # Warn the user at the top of the form that there were errors. |
391 | # Note that there will also be per-field feedback on |
392 | # validation errors because of '$w->process($c->req)' above. |
393 | $c->stash->{error_msg} = 'Validation errors!'; |
394 | } else { |
395 | # Everything validated OK, so do the create |
396 | # Call create() on the book model object. Pass the table |
397 | # columns/field values we want to set as hash values |
398 | my $book = $c->model('MyAppDB::Book')->create({ |
399 | title => $title, |
400 | rating => $rating |
401 | }); |
402 | |
403 | # Add a record to the join table for this book, mapping to |
404 | # appropriate author. Note that $authors will be 1 author as |
405 | # a scalar or ref to list of authors depending on how many the |
406 | # user selected; the 'ref $authors ?...' handles both cases |
407 | foreach my $author (ref $authors ? @$authors : $authors) { |
408 | $book->add_to_book_authors({author_id => $author}); |
409 | } |
410 | # Set a status message for the user |
411 | $c->stash->{status_msg} = 'Book created'; |
412 | } |
413 | |
414 | # Set the template |
415 | $c->stash->{template} = 'books/hw_form.tt2'; |
416 | } |
417 | |
418 | The key changes to C<hw_create_do> are: |
419 | |
420 | =over 4 |
421 | |
422 | =item * |
423 | |
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424 | C<hw_create_do> no longer does a C<detach> to C<hw_create> to redisplay |
425 | the form. Now that C<hw_create_do> has to process the form in order to |
426 | perform the validation, we go ahead and build a complete set of form |
427 | presentation logic into C<hw_create_do> (for example, C<hw_create_do> |
428 | now has a C<$c-E<gt>stash-E<gt>{template}> line). Note that if we |
429 | process the form in C<hw_create_do> I<and> forward/detach back to |
430 | <hw_create>, we would end up with C<make_book_widget> being called |
431 | twice, resulting in a duplicate set of elements being added to the form. |
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432 | (There are other ways to address the "duplicate form rendering" issue -- |
433 | just be aware that it exists.) |
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434 | |
435 | =item * |
436 | |
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437 | C<$w-E<gt>process($c-E<gt>req)> is called to run the validation logic. |
438 | Not only does this set the C<has_errors> flag if validation errors are |
439 | encountered, it returns a string containing any field-specific warning |
440 | messages. |
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441 | |
442 | =item * |
443 | |
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444 | An C<if> statement checks if any validation errors were encountered. If |
445 | so, C<$c-E<gt>stash-E<gt>{error_msg}> is set and the input form is |
446 | redisplayed. If no errors were found, the object is created in a manner |
447 | similar to the prior version of the C<hw_create_do> method. |
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448 | |
449 | =back |
450 | |
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451 | =head2 Try Out the Form |
452 | |
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453 | Press C<Ctrl-C> to kill the previous server instance (if it's still |
454 | running) and restart it: |
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455 | |
456 | $ script/myapp_server.pl |
457 | |
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458 | Now try adding a book with various errors: title less than 5 characters, |
459 | non-numeric rating, a rating of 0 or 6, etc. Also try selecting one, |
460 | two, and zero authors. When you click Submit, the HTML::Widget |
461 | C<constraint> items will validate the logic and insert feedback as |
462 | appropriate. |
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463 | |
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464 | |
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465 | =head1 Enable C<DBIx::Class::HTMLWidget> Support |
466 | |
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467 | In this section we will take advantage of some of the "auto-population" |
468 | features of C<DBIx::Class::HTMLWidget>. Enabling |
469 | C<DBIx::Class::HTMLWidget> provides two additional methods to your DBIC |
470 | model classes: |
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471 | |
472 | =over 4 |
473 | |
474 | =item * |
475 | |
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476 | fill_widget() |
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477 | |
478 | Takes data from the database and transfers it to your form widget. |
479 | |
480 | =item * |
481 | |
482 | populate_from_widget() |
483 | |
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484 | Takes data from a form widget and uses it to update the corresponding |
485 | records in the database. |
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486 | |
487 | =back |
488 | |
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489 | In other words, the two methods are a mirror image of each other: one |
490 | reads from the database while the other writes to the database. |
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491 | |
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492 | =head2 Add C<DBIx::Class::HTMLWidget> to DBIC Model |
493 | |
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494 | In order to use L<DBIx::Class::HTMLWidget|DBIx::Class::HTMLWidget>, we |
495 | need to add C<HTMLWidget> to the C<load_components> line of DBIC result |
496 | source files that need to use the C<fill_widget> and |
497 | C<populate_from_widget> methods. In this case, open |
498 | C<lib/MyAppDB/Book.pm> and update the C<load_components> line to match: |
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499 | |
500 | __PACKAGE__->load_components(qw/PK::Auto Core HTMLWidget/); |
501 | |
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502 | =head2 Use C<populate_from_widget> in C<hw_create_do> |
503 | |
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504 | Edit C<lib/MyApp/Controller/Books.pm> and update C<hw_create_do> to |
505 | match the following code: |
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506 | |
507 | =head2 hw_create_do |
508 | |
509 | Build an HTML::Widget form for book creation and updates |
510 | |
511 | =cut |
512 | |
513 | sub hw_create_do : Local { |
514 | my ($self, $c) = @_; |
515 | |
516 | # Create the widget and set the action for the form |
517 | my $w = $self->make_book_widget($c); |
518 | $w->action($c->uri_for('hw_create_do')); |
519 | |
520 | # Validate the form parameters |
521 | my $result = $w->process($c->req); |
522 | |
523 | # Write form (including validation error messages) to |
524 | # stash variable for use in template |
525 | $c->stash->{widget_result} = $result; |
526 | |
527 | # Were their validation errors? |
528 | if ($result->has_errors) { |
529 | # Warn the user at the top of the form that there were errors. |
530 | # Note that there will also be per-field feedback on |
531 | # validation errors because of '$w->process($c->req)' above. |
532 | $c->stash->{error_msg} = 'Validation errors!'; |
533 | } else { |
534 | my $book = $c->model('MyAppDB::Book')->new({}); |
535 | $book->populate_from_widget($result); |
536 | |
537 | # Add a record to the join table for this book, mapping to |
538 | # appropriate author. Note that $authors will be 1 author as |
539 | # a scalar or ref to list of authors depending on how many the |
540 | # user selected; the 'ref $authors ?...' handles both cases |
541 | my $authors = $c->request->params->{authors}; |
542 | foreach my $author (ref $authors ? @$authors : $authors) { |
543 | $book->add_to_book_authors({author_id => $author}); |
544 | } |
545 | |
546 | # Set a status message for the user |
547 | $c->stash->{status_msg} = 'Book created'; |
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548 | |
549 | # Redisplay an empty form for another |
550 | $c->stash->{widget_result} = $w->result; |
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551 | } |
552 | |
553 | # Set the template |
554 | $c->stash->{template} = 'books/hw_form.tt2'; |
555 | } |
556 | |
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557 | In this version of C<hw_create_do> we removed the logic that manually |
558 | pulled the form variables and used them to call |
559 | C<$c-E<gt>model('MyAppDB::Book')-E<gt>create> and replaced it with a |
560 | single call to C<$book-E<gt>populate_from_widget>. Note that we still |
561 | have to call C<$book-E<gt>add_to_book_authors> once per author because |
562 | C<populate_from_widget> does not currently handle the relationships |
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563 | between tables. Also, we reset the form to an empty fields by adding |
564 | another call to C<$w-E<gt>result> and storing the output in the stash |
565 | (if we don't override the output from C<$w-E<gt>process($c-E<gt>req)>, |
566 | the form values already entered will be retained on redisplay -- |
567 | although this could be desirable for some applications, we avoid it |
568 | here to help avoid the creation of duplicate records). |
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569 | |
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570 | |
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571 | =head2 Try Out the Form |
572 | |
573 | Press C<Ctrl-C> to kill the previous server instance (if it's still |
574 | running) and restart it: |
575 | |
576 | $ script/myapp_server.pl |
577 | |
578 | Try adding a book that validate. Return to the book list and the book |
579 | you added should be visible. |
580 | |
581 | |
582 | |
583 | =head1 Rendering C<HTMLWidget> Forms in a Table |
584 | |
585 | Some developers my wish to use the "old-fashioned" table style of |
586 | rendering a form in lieu of the default C<HTML::Widget> rendering that |
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587 | assumes you will use CSS for formatting. This section demonstrates |
588 | some techniques that can override the default rendering with a |
589 | custom class. |
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590 | |
591 | |
592 | =head2 Add a New "Element Container" |
593 | |
594 | Open C<lib/FormElementContainer.pm> in your editor and enter: |
595 | |
596 | package FormElementContainer; |
597 | |
598 | use base 'HTML::Widget::Container'; |
599 | |
600 | sub _build_element { |
601 | my ($self, $element) = @_; |
602 | |
603 | return () unless $element; |
604 | if (ref $element eq 'ARRAY') { |
605 | return map { $self->_build_element($_) } @{$element}; |
606 | } |
607 | my $e = $element->clone; |
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608 | $e = new HTML::Element('span', class => 'fields_with_errors')->push_content($e) |
609 | if $self->error && $e->tag eq 'input'; |
610 | |
611 | return $e ? ($e) : (); |
612 | } |
613 | |
614 | 1; |
615 | |
616 | This simply dumps the HTML code for a given form element, followed by a |
617 | C<span> that can contain validation error message. |
618 | |
619 | |
620 | =head2 Enable the New Element Container When Building the Form |
621 | |
622 | Open C<lib/MyApp/Controller/Books.pm> in your editor. First add a |
623 | C<use> for your element container class: |
624 | |
625 | use FormElementContainer; |
626 | |
fb39c27a |
627 | B<Note:> If you forget to C<use> your container class in your |
628 | controller, then your form will not be displayed and no error messages |
629 | will be generated. Don't forget this important step! |
630 | |
785c4199 |
631 | Then tell C<HTML::Widget> to use that class during rendering by updating |
632 | C<make_book_widget> to match the following: |
633 | |
634 | sub make_book_widget { |
635 | my ($self, $c) = @_; |
636 | |
637 | # Create an HTML::Widget to build the form |
638 | my $w = $c->widget('book_form')->method('post'); |
639 | |
640 | # ***New: Use custom class to render each element in the form |
641 | $w->element_container_class('FormElementContainer'); |
642 | |
643 | # Get authors |
644 | my @authorObjs = $c->model("MyAppDB::Author")->all(); |
645 | my @authors = map {$_->id => $_->last_name } |
646 | sort {$a->last_name cmp $b->last_name} @authorObjs; |
647 | |
648 | # Create the form feilds |
649 | $w->element('Textfield', 'title' )->label('Title')->size(60); |
650 | $w->element('Textfield', 'rating' )->label('Rating')->size(1); |
651 | # Convert to multi-select list |
652 | $w->element('Select', 'authors')->label('Authors') |
653 | ->options(@authors)->multiple(1)->size(3); |
654 | $w->element('Submit', 'submit' )->value('submit'); |
655 | |
656 | # Set constraints |
657 | $w->constraint(All => qw/title rating authors/) |
658 | ->message('Required. '); |
659 | $w->constraint(Integer => qw/rating/) |
660 | ->message('Must be an integer. '); |
661 | $w->constraint(Range => qw/rating/)->min(1)->max(5) |
662 | ->message('Must be a number between 1 and 5. '); |
663 | $w->constraint(Length => qw/title/)->min(5)->max(50) |
664 | ->message('Must be between 5 and 50 characters. '); |
665 | |
666 | # Set filters |
667 | for my $column (qw/title rating authors/) { |
668 | $w->filter( HTMLEscape => $column ); |
669 | $w->filter( TrimEdges => $column ); |
670 | } |
671 | |
672 | # Return the widget |
673 | return $w; |
674 | } |
675 | |
676 | The two new lines are marked with C<***New:>. |
677 | |
678 | |
679 | =head2 Update the TT Template |
680 | |
681 | Open C<root/src/books/hw_form.tt2> and edit it to match: |
682 | |
683 | [% META title = 'Create/Update Book' %] |
684 | |
685 | [%# Comment out the auto-rendered form %] |
686 | [%# widget_result.as_xml %] |
687 | |
688 | |
689 | [%# Iterate over the form elements and display each -%] |
690 | <form name="book_form" action="[% widget_result.action %]" method="post"> |
691 | <table border="0"> |
692 | [% FOREACH element = widget_result.elements %] |
693 | <tr> |
694 | <td class="form-label"> |
695 | [% element.label.as_text %] |
696 | </td> |
697 | <td class="form-element"> |
698 | [% element.element_xml %] |
699 | <span class="form-error"> |
700 | [% element.error_xml %] |
701 | </span> |
702 | </td> |
703 | </tr> |
704 | [% END %] |
705 | </table> |
706 | </form> |
707 | |
708 | |
709 | <p><a href="[% Catalyst.uri_for('list') %]">Return to book list</a></p> |
710 | |
711 | |
712 | [%# A little JavaScript to move the cursor to the first field %] |
713 | <script LANGUAGE="JavaScript"> |
714 | document.book_form.book_form_title.focus(); |
715 | </script> |
716 | |
717 | This represents three changes: |
718 | |
719 | =over 4 |
720 | |
721 | =item * |
722 | |
723 | The existing C<widget_result.as_xml> has been commented out. |
724 | |
725 | =item * |
726 | |
727 | It loops through each form element, displaying the field name in the |
728 | first table cell along with the form element and validation errors in |
729 | the second field. |
730 | |
731 | =item * |
732 | |
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733 | JavaScript to position the user's cursor in the first field of the form. |
785c4199 |
734 | |
735 | =back |
736 | |
737 | |
738 | =head2 Try Out the Form |
739 | |
740 | Press C<Ctrl-C> to kill the previous server instance (if it's still |
741 | running) and restart it: |
742 | |
743 | $ script/myapp_server.pl |
744 | |
745 | Try adding a book that validate. Return to the book list and the book |
746 | you added should be visible. |
747 | |
748 | |
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749 | =head1 AUTHOR |
750 | |
751 | Kennedy Clark, C<hkclark@gmail.com> |
752 | |
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753 | Please report any errors, issues or suggestions to the author. The |
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754 | most recent version of the Catalyst Tutorial can be found at |
be16bacd |
755 | L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Runtime/lib/Catalyst/Manual/Tutorial/>. |
4d583dd8 |
756 | |
cc548726 |
757 | Copyright 2006, Kennedy Clark, under Creative Commons License |
758 | (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>). |