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1 | =head1 NAME |
2 | |
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3 | Catalyst::Manual::Tutorial::CatalystBasics - Catalyst Tutorial - Part 2: Catalyst Application Development Basics |
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4 | |
5 | |
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6 | =head1 OVERVIEW |
7 | |
8 | This is B<Part 2 of 9> for the Catalyst tutorial. |
9 | |
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10 | L<Tutorial Overview|Catalyst::Manual::Tutorial> |
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11 | |
12 | =over 4 |
13 | |
14 | =item 1 |
15 | |
16 | L<Introduction|Catalyst::Manual::Tutorial::Intro> |
17 | |
18 | =item 2 |
19 | |
20 | B<Catalyst Basics> |
21 | |
22 | =item 3 |
23 | |
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24 | L<Basic CRUD|Catalyst::Manual::Tutorial::BasicCRUD> |
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25 | |
26 | =item 4 |
27 | |
28 | L<Authentication|Catalyst::Manual::Tutorial::Authentication> |
29 | |
30 | =item 5 |
31 | |
32 | L<Authorization|Catalyst::Manual::Tutorial::Authorization> |
33 | |
34 | =item 6 |
35 | |
36 | L<Debugging|Catalyst::Manual::Tutorial::Debugging> |
37 | |
38 | =item 7 |
39 | |
40 | L<Testing|Catalyst::Manual::Tutorial::Testing> |
41 | |
42 | =item 8 |
43 | |
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44 | L<Advanced CRUD|Catalyst::Manual::Tutorial::AdvancedCRUD> |
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45 | |
46 | =item 9 |
47 | |
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48 | L<Appendices|Catalyst::Manual::Tutorial::Appendices> |
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49 | |
50 | =back |
51 | |
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52 | |
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53 | =head1 DESCRIPTION |
54 | |
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55 | In this part of the tutorial, we will create a very basic Catalyst web |
56 | application. Though simple in many respects, this section will already |
57 | demonstrate a number of powerful capabilities such as: |
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58 | |
59 | =over 4 |
60 | |
61 | =item * Helper Scripts |
62 | |
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63 | Catalyst helper scripts that can be used to rapidly bootstrap the |
64 | skeletal structure of an application. |
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65 | |
66 | =item * MVC |
67 | |
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68 | Model/View/Controller (MVC) provides an architecture that facilitates a |
69 | clean "separation of control" between the different portions of your |
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70 | application. Given that many other documents cover this subject in |
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71 | detail, MVC will not be discussed in depth here (for an excellent |
72 | introduction to MVC and general Catalyst concepts, please see |
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73 | L<Catalyst::Manual::About>. In short: |
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74 | |
75 | =over 4 |
76 | |
77 | =item * Model |
78 | |
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79 | The model usually represents a data store. In most applications, the |
80 | model equates to the objects that are created from and saved to your SQL |
81 | database. |
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82 | |
83 | =item * View |
84 | |
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85 | The view takes model objects and renders them into something for the end |
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86 | user to look at. Normally this involves a template-generation tool that |
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87 | creates HTML for the user's web browser, but it could easily be code |
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88 | that generates other forms such as PDF documents, e-mails, or Excel |
89 | spreadsheets. |
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90 | |
91 | =item * Controller |
92 | |
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93 | As suggested by its name, the controller takes user requests and routes |
94 | them to the necessary model and view. |
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95 | |
96 | =back |
97 | |
98 | =item * ORM |
99 | |
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100 | The use of Object-Relational Mapping (ORM) technology for database |
101 | access. Specifically, ORM provides an automated and standardized means |
102 | to persist and restore objects to/from a relational database. |
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103 | |
104 | =back |
105 | |
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106 | B<TIP>: Note that all of the code for this part of the tutorial can be |
107 | pulled from the Catalyst Subversion repository in one step with the |
108 | following command: |
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109 | |
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110 | svn co http://dev.catalyst.perl.org/repos/Catalyst/tags/examples/Tutorial/MyApp/5.7/CatalystBasics MyApp |
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111 | |
112 | |
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113 | =head1 CREATE A CATALYST PROJECT |
114 | |
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115 | Catalyst provides a number of helper scripts that can be used to quickly |
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116 | flesh out the basic structure of your application. All Catalyst projects |
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117 | begin with the C<catalyst.pl> helper (see L<Catalyst::Helper|Catalyst::Helper> |
118 | for more information on helpers). Also note that as of Catalyst 5.7000, |
119 | you will not have the helper scripts unless you install both |
120 | L<Catalyst::Runtime|Catalyst::Runtime> and L<Catalyst::Devel|Catalyst::Devel>. |
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121 | |
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122 | In the case of this tutorial, use the Catalyst C<catalyst.pl> script to |
123 | initialize the framework for an application called C<MyApp>: |
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124 | |
125 | $ catalyst.pl MyApp |
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126 | created "MyApp" |
127 | created "MyApp/script" |
128 | created "MyApp/lib" |
129 | created "MyApp/root" |
130 | ... |
131 | created "MyApp/script/myapp_create.pl" |
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132 | $ cd MyApp |
133 | |
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134 | The C<catalyst.pl> helper script will display the names of the |
135 | directories and files it creates. |
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136 | |
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137 | Though it's too early for any significant celebration, we already have a |
138 | functioning application. Run the following command to run this |
139 | application with the built-in development web server: |
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140 | |
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141 | $ script/myapp_server.pl |
142 | [debug] Debug messages enabled |
143 | [debug] Loaded plugins: |
144 | .----------------------------------------------------------------------------. |
145 | | Catalyst::Plugin::ConfigLoader 0.06 | |
146 | | Catalyst::Plugin::Static::Simple 0.14 | |
147 | '----------------------------------------------------------------------------' |
148 | |
149 | [debug] Loaded dispatcher "Catalyst::Dispatcher" |
150 | [debug] Loaded engine "Catalyst::Engine::HTTP" |
151 | [debug] Found home "/root/dev/MyApp" |
152 | [debug] Loaded components: |
153 | .-----------------------------------------------------------------+----------. |
154 | | Class | Type | |
155 | +-----------------------------------------------------------------+----------+ |
156 | | MyApp::Controller::Root | instance | |
157 | '-----------------------------------------------------------------+----------' |
158 | |
159 | [debug] Loaded Private actions: |
160 | .----------------------+--------------------------------------+--------------. |
161 | | Private | Class | Method | |
162 | +----------------------+--------------------------------------+--------------+ |
163 | | /default | MyApp::Controller::Root | default | |
164 | | /end | MyApp::Controller::Root | end | |
165 | '----------------------+--------------------------------------+--------------' |
166 | |
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167 | [info] MyApp powered by Catalyst 5.7000 |
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168 | You can connect to your server at http://localhost.localdomain:3000 |
169 | |
170 | Point your web browser to L<http://localhost:3000> (substituting a |
171 | different hostname or IP address as appropriate) and you should be |
172 | greeted by the Catalyst welcome screen. Information similar to the |
173 | following should be appended to the logging output of the development |
174 | server: |
175 | |
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176 | [info] *** Request 1 (0.043/s) [6003] [Fri Jul 7 13:32:53 2006] *** |
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177 | [debug] "GET" request for "/" from "127.0.0.1" |
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178 | [info] Request took 0.067675s (14.777/s) |
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179 | .----------------------------------------------------------------+-----------. |
180 | | Action | Time | |
181 | +----------------------------------------------------------------+-----------+ |
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182 | | /default | 0.002844s | |
183 | | /end | 0.000207s | |
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184 | '----------------------------------------------------------------+-----------' |
185 | |
186 | Press Ctrl-C to break out of the development server. |
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187 | |
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188 | |
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189 | =head1 CREATE A SQLITE DATABASE |
190 | |
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191 | In this step, we make a text file with the required SQL commands to |
192 | create a database table and load some sample data. Open C<myapp01.sql> |
193 | in your editor and enter: |
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194 | |
195 | -- |
196 | -- Create a very simple database to hold book and author information |
197 | -- |
198 | CREATE TABLE books ( |
199 | id INTEGER PRIMARY KEY, |
200 | title TEXT , |
201 | rating INTEGER |
202 | ); |
203 | -- 'book_authors' is a many-to-many join table between books & authors |
204 | CREATE TABLE book_authors ( |
205 | book_id INTEGER, |
206 | author_id INTEGER, |
207 | PRIMARY KEY (book_id, author_id) |
208 | ); |
209 | CREATE TABLE authors ( |
210 | id INTEGER PRIMARY KEY, |
211 | first_name TEXT, |
212 | last_name TEXT |
213 | ); |
214 | --- |
215 | --- Load some sample data |
216 | --- |
217 | INSERT INTO books VALUES (1, 'CCSP SNRS Exam Certification Guide', 5); |
218 | INSERT INTO books VALUES (2, 'TCP/IP Illustrated, Volume 1', 5); |
219 | INSERT INTO books VALUES (3, 'Internetworking with TCP/IP Vol.1', 4); |
220 | INSERT INTO books VALUES (4, 'Perl Cookbook', 5); |
221 | INSERT INTO books VALUES (5, 'Designing with Web Standards', 5); |
222 | INSERT INTO authors VALUES (1, 'Greg', 'Bastien'); |
223 | INSERT INTO authors VALUES (2, 'Sara', 'Nasseh'); |
224 | INSERT INTO authors VALUES (3, 'Christian', 'Degu'); |
225 | INSERT INTO authors VALUES (4, 'Richard', 'Stevens'); |
226 | INSERT INTO authors VALUES (5, 'Douglas', 'Comer'); |
227 | INSERT INTO authors VALUES (6, 'Tom', 'Christiansen'); |
228 | INSERT INTO authors VALUES (7, ' Nathan', 'Torkington'); |
229 | INSERT INTO authors VALUES (8, 'Jeffrey', 'Zeldman'); |
230 | INSERT INTO book_authors VALUES (1, 1); |
231 | INSERT INTO book_authors VALUES (1, 2); |
232 | INSERT INTO book_authors VALUES (1, 3); |
233 | INSERT INTO book_authors VALUES (2, 4); |
234 | INSERT INTO book_authors VALUES (3, 5); |
235 | INSERT INTO book_authors VALUES (4, 6); |
236 | INSERT INTO book_authors VALUES (4, 7); |
237 | INSERT INTO book_authors VALUES (5, 8); |
238 | |
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239 | B<TIP>: See Appendix 1 for tips on removing the leading spaces when |
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240 | cutting and pasting example code from POD-based documents. |
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241 | |
242 | Then use the following command to build a C<myapp.db> SQLite database: |
243 | |
244 | $ sqlite3 myapp.db < myapp01.sql |
245 | |
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246 | If you need to create the database more than once, you probably want to |
247 | issue the C<rm myapp.db> command to delete the database before you use |
248 | the C<sqlite3 myapp.db < myapp01.sql> command. |
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249 | |
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250 | Once the C<myapp.db> database file has been created and initialized, you |
251 | can use the SQLite command line environment to do a quick dump of the |
252 | database contents: |
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253 | |
254 | $ sqlite3 myapp.db |
255 | SQLite version 3.2.2 |
256 | Enter ".help" for instructions |
257 | sqlite> select * from books; |
258 | 1|CCSP SNRS Exam Certification Guide|5 |
259 | 2|TCP/IP Illustrated, Volume 1|5 |
260 | 3|Internetworking with TCP/IP Vol.1|4 |
261 | 4|Perl Cookbook|5 |
262 | 5|Designing with Web Standards|5 |
263 | sqlite> .q |
264 | $ |
265 | |
266 | Or: |
267 | |
268 | $ sqlite3 myapp.db "select * from books" |
269 | 1|CCSP SNRS Exam Certification Guide|5 |
270 | 2|TCP/IP Illustrated, Volume 1|5 |
271 | 3|Internetworking with TCP/IP Vol.1|4 |
272 | 4|Perl Cookbook|5 |
273 | 5|Designing with Web Standards|5 |
274 | |
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275 | As with most other SQL tools, if you are using the full "interactive" |
276 | environment you need to terminate your SQL commands with a ";" (it's not |
277 | required if you do a single SQL statement on the command line). Use |
278 | ".q" to exit from SQLite from the SQLite interactive mode and return to |
279 | your OS command prompt. |
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280 | |
281 | |
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282 | =head1 EDIT THE LIST OF CATALYST PLUGINS |
283 | |
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284 | One of the greatest benefits of Catalyst is that it has such a large |
285 | library of plugins available. Plugins are used to seamlessly integrate |
286 | existing Perl modules into the overall Catalyst framework. In general, |
287 | they do this by adding additional methods to the C<context> object |
288 | (generally written as C<$c>) that Catalyst passes to every component |
289 | throughout the framework. |
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290 | |
291 | By default, Catalyst enables three plugins/flags: |
292 | |
293 | =over 4 |
294 | |
295 | =item * |
296 | |
297 | C<-Debug> Flag |
298 | |
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299 | Enables the Catalyst debug output you saw when we started the |
300 | C<script/myapp_server.pl> development server earlier. You can remove |
301 | this plugin when you place your application into production. |
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302 | |
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303 | As you may have noticed, C<-Debug> is not a plugin, but a I<flag>. |
304 | Although most of the items specified on the C<use Catalyst> line of your |
305 | application class will be plugins, Catalyst supports a limited number of |
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306 | flag options (of these, C<-Debug> is the most common). See the |
307 | documentation for C<Catalyst.pm> to get details on other flags |
308 | (currently C<-Engine>, C<-Home>, and C<-Log>). |
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309 | |
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310 | If you prefer, you can use the C<$c-E<gt>debug> method to enable debug |
311 | messages. |
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312 | |
313 | =item * |
314 | |
315 | L<Catalyst::Plugin::ConfigLoader|Catalyst::Plugin::ConfigLoader> |
316 | |
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317 | C<ConfigLoader> provides an automatic way to load configurable |
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318 | parameters for your application from a central YAML file (versus having |
319 | the values hard-coded inside your Perl modules). If you have not been |
320 | exposed to YAML before, it is a human-readable data serialization format |
321 | that can be used to read (and write) values to/from text files. We will |
322 | see how to use this feature of Catalyst during the authentication and |
323 | authorization sections (Part 4 and Part 5). |
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324 | |
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325 | =item * |
326 | |
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327 | L<Catalyst::Plugin::Static::Simple|Catalyst::Plugin::Static::Simple> |
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328 | |
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329 | C<Static::Simple> provides an easy method of serving static content such |
330 | as images and CSS files under the development server. |
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331 | |
332 | =back |
333 | |
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334 | To modify the list of plugins, edit C<lib/MyApp.pm> (this file is |
335 | generally referred to as your I<application class>) and delete the line |
336 | with: |
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337 | |
338 | use Catalyst qw/-Debug ConfigLoader Static::Simple/; |
339 | |
340 | Replace it with: |
341 | |
342 | use Catalyst qw/ |
343 | -Debug |
344 | ConfigLoader |
345 | Static::Simple |
346 | |
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347 | StackTrace |
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348 | /; |
349 | |
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350 | This tells Catalyst to start using one new plugin: |
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351 | |
352 | =over 4 |
353 | |
354 | =item * |
355 | |
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356 | L<Catalyst::Plugin::StackTrace|Catalyst::Plugin::StackTrace> |
357 | |
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358 | Adds a stack trace to the standard Catalyst "debug screen" (this is the |
359 | screen Catalyst sends to your browser when an error occurs). |
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360 | |
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361 | Note: L<StackTrace|Catalyst::Plugin::StackTrace> output appears in your |
362 | browser, not in the console window from which you're running your |
363 | application, which is where logging output usually goes. |
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364 | |
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365 | =back |
366 | |
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367 | Note that when specifying plugins on the C<use Catalyst> line, you can |
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368 | omit C<Catalyst::Plugin::> from the name. Additionally, you can spread |
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369 | the plugin names across multiple lines as shown here, or place them all |
370 | on one (or more) lines as with the default configuration. |
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371 | |
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372 | B<TIP:> You may see examples that include the |
373 | L<Catalyst::Plugin::DefaultEnd|Catalyst::Plugin::DefaultEnd> |
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374 | plugins. As of Catalyst 5.7000, C<DefaultEnd> has been |
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375 | deprecated in favor of |
376 | L<Catalyst::Action::RenderView|Catalyst::Action::RenderView> |
377 | (as the name of the package suggests, C<RenderView> is not |
378 | a plugin, but an action). The purpose of both is essentially the same: |
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379 | forward processing to the view to be rendered. Applications generated |
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380 | under 5.7000 should automatically use C<RenderView> and "just work" |
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381 | for most applications. For more information on C<RenderView> and |
382 | the various options for forwarding to your view logic, please refer |
383 | to the "Using RenderView for the Default View" section under |
384 | "CATALYST VIEWS" below. |
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385 | |
386 | |
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387 | =head1 DATABASE ACCESS WITH C<DBIx::Class> |
388 | |
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389 | Catalyst can be used with virtually any form of persistent datastore |
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390 | available via Perl. For example, |
391 | L<Catalyst::Model::DBI|Catalyst::Model::DBI> can be used to |
392 | easily access databases through the traditional Perl C<DBI> interface. |
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393 | However, most Catalyst applications use some form of ORM technology to |
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394 | automatically create and save model objects as they are used. Although |
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395 | Tony Bowden's L<Class::DBI|Class::DBI> has been the traditional |
396 | Perl ORM engine, Matt Trout's L<DBIx::Class|DBIx::Class> (abbreviated |
397 | as "DBIC") has rapidly emerged as the Perl-based ORM technology of choice. |
398 | Most new Catalyst applications rely on DBIC, as will this tutorial. |
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399 | |
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400 | Note: See L<Catalyst:: Model::CDBI> for more information on using |
401 | Catalyst with L<Class::DBI|Class::DBI>. |
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402 | |
403 | =head2 Create a DBIC Schema File |
404 | |
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405 | DBIx::Class uses a schema file to load other classes that represent the |
406 | tables in your database (DBIC refers to these "table objects" as "result |
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407 | sources"; see L<DBIx::Class::ResultSource>). In this case, we want to |
408 | load the model object for the C<books>, C<book_authors>, and C<authors> |
409 | tables created in the previous step. |
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410 | |
411 | Open C<lib/MyAppDB.pm> in your editor and insert: |
412 | |
413 | package MyAppDB; |
414 | |
415 | =head1 NAME |
416 | |
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417 | MyAppDB - DBIC Schema Class |
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418 | |
419 | =cut |
420 | |
421 | # Our schema needs to inherit from 'DBIx::Class::Schema' |
422 | use base qw/DBIx::Class::Schema/; |
423 | |
424 | # Need to load the DB Model classes here. |
425 | # You can use this syntax if you want: |
426 | # __PACKAGE__->load_classes(qw/Book BookAuthor Author/); |
427 | # Also, if you simply want to load all of the classes in a directory |
428 | # of the same name as your schema class (as we do here) you can use: |
429 | # __PACKAGE__->load_classes(qw//); |
430 | # But the variation below is more flexible in that it can be used to |
431 | # load from multiple namespaces. |
432 | __PACKAGE__->load_classes({ |
433 | MyAppDB => [qw/Book BookAuthor Author/] |
434 | }); |
435 | |
436 | 1; |
437 | |
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438 | B<Note:> C<__PACKAGE__> is just a shorthand way of referencing the name |
439 | of the package where it is used. Therefore, in C<MyAppDB.pm>, |
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440 | C<__PACKAGE__> is equivalent to C<MyAppDB>. |
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441 | |
442 | |
443 | =head2 Create the DBIC "Result Source" Files |
444 | |
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445 | In this step, we create "table classes" (again, these are called a |
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446 | "result source" classes in DBIC) that act as model objects for the |
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447 | C<books>, C<book_authors>, and C<authors> tables in our database. |
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448 | |
449 | First, create a directory to hold the class: |
450 | |
451 | $ mkdir lib/MyAppDB |
452 | |
453 | Then open C<lib/MyAppDB/Book.pm> in your editor and enter: |
454 | |
455 | package MyAppDB::Book; |
456 | |
457 | use base qw/DBIx::Class/; |
458 | |
459 | # Load required DBIC stuff |
460 | __PACKAGE__->load_components(qw/PK::Auto Core/); |
461 | # Set the table name |
462 | __PACKAGE__->table('books'); |
463 | # Set columns in table |
464 | __PACKAGE__->add_columns(qw/id title rating/); |
465 | # Set the primary key for the table |
466 | __PACKAGE__->set_primary_key(qw/id/); |
467 | |
468 | # |
469 | # Set relationships: |
470 | # |
471 | |
472 | # has_many(): |
473 | # args: |
474 | # 1) Name of relationship, DBIC will create accessor with this name |
475 | # 2) Name of the model class referenced by this relationship |
476 | # 3) Column name in *foreign* table |
477 | __PACKAGE__->has_many(book_authors => 'MyAppDB::BookAuthor', 'book_id'); |
478 | |
479 | # many_to_many(): |
480 | # args: |
481 | # 1) Name of relationship, DBIC will create accessor with this name |
482 | # 2) Name of has_many() relationship this many_to_many() is shortcut for |
483 | # 3) Name of belongs_to() relationship in model class of has_many() above |
484 | # You must already have the has_many() defined to use a many_to_many(). |
485 | __PACKAGE__->many_to_many(authors => 'book_authors', 'author'); |
486 | |
487 | |
488 | =head1 NAME |
489 | |
490 | MyAppDB::Book - A model object representing a book. |
491 | |
492 | =head1 DESCRIPTION |
493 | |
494 | This is an object that represents a row in the 'books' table of your application |
495 | database. It uses DBIx::Class (aka, DBIC) to do ORM. |
496 | |
497 | For Catalyst, this is designed to be used through MyApp::Model::MyAppDB. |
498 | Offline utilities may wish to use this class directly. |
499 | |
500 | =cut |
501 | |
502 | 1; |
503 | |
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504 | This defines both a C<has_many> and a C<many_to_many> relationship. The |
505 | C<many_to_many> relationship is optional, but it makes it easier to map |
506 | a book to its collection of authors. Without it, we would have to |
507 | "walk" though the C<book_authors> table as in |
508 | C<$book-E<gt>book_authors-E<gt>first-E<gt>author-E<gt>last_name> (we |
509 | will see examples on how to use DBIC objects in your code soon, but note |
510 | that because C<$book-E<gt>book_authors> can return multiple authors, we |
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511 | have to use C<first> to display a single author). C<many_to_many> allows |
512 | us to use the shorter C<$book-E<gt>authors-E<gt>first-E<gt>last_name>. |
513 | Note that you cannot define a C<many_to_many> relationship without also |
514 | having the C<has_many> relationship in place. |
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515 | |
516 | Next, open C<lib/MyAppDB/Author.pm> in your editor and enter: |
517 | |
518 | package MyAppDB::Author; |
519 | |
520 | use base qw/DBIx::Class/; |
521 | |
522 | # Load required DBIC stuff |
523 | __PACKAGE__->load_components(qw/PK::Auto Core/); |
524 | # Set the table name |
525 | __PACKAGE__->table('authors'); |
526 | # Set columns in table |
527 | __PACKAGE__->add_columns(qw/id first_name last_name/); |
528 | # Set the primary key for the table |
529 | __PACKAGE__->set_primary_key(qw/id/); |
208513f1 |
530 | |
4d583dd8 |
531 | # |
532 | # Set relationships: |
533 | # |
534 | |
535 | # has_many(): |
536 | # args: |
537 | # 1) Name of relationship, DBIC will create accessor with this name |
538 | # 2) Name of the model class referenced by this relationship |
539 | # 3) Column name in *foreign* table |
540 | __PACKAGE__->has_many(book_author => 'MyAppDB::BookAuthor', 'author_id'); |
541 | |
542 | # many_to_many(): |
543 | # args: |
544 | # 1) Name of relationship, DBIC will create accessor with this name |
545 | # 2) Name of has_many() relationship this many_to_many() is shortcut for |
546 | # 3) Name of belongs_to() relationship in model class of has_many() above |
547 | # You must already have the has_many() defined to use a many_to_many(). |
548 | __PACKAGE__->many_to_many(books => 'book_author', 'book'); |
549 | |
550 | |
551 | =head1 NAME |
552 | |
553 | MyAppDB::Author - A model object representing an author of a book (if a book has |
554 | multiple authors, each will be represented be separate Author object). |
555 | |
556 | =head1 DESCRIPTION |
557 | |
558 | This is an object that represents a row in the 'authors' table of your application |
559 | database. It uses DBIx::Class (aka, DBIC) to do ORM. |
560 | |
561 | For Catalyst, this is designed to be used through MyApp::Model::MyAppDB. |
562 | Offline utilities may wish to use this class directly. |
563 | |
564 | =cut |
565 | |
566 | 1; |
567 | |
568 | Finally, open C<lib/MyAppDB/BookAuthor.pm> in your editor and enter: |
569 | |
570 | package MyAppDB::BookAuthor; |
571 | |
572 | use base qw/DBIx::Class/; |
573 | |
574 | # Load required DBIC stuff |
575 | __PACKAGE__->load_components(qw/PK::Auto Core/); |
576 | # Set the table name |
577 | __PACKAGE__->table('book_authors'); |
578 | # Set columns in table |
579 | __PACKAGE__->add_columns(qw/book_id author_id/); |
580 | # Set the primary key for the table |
581 | __PACKAGE__->set_primary_key(qw/book_id author_id/); |
582 | |
583 | # |
584 | # Set relationships: |
585 | # |
586 | |
587 | # belongs_to(): |
588 | # args: |
589 | # 1) Name of relationship, DBIC will create accessor with this name |
590 | # 2) Name of the model class referenced by this relationship |
591 | # 3) Column name in *this* table |
592 | __PACKAGE__->belongs_to(book => 'MyAppDB::Book', 'book_id'); |
208513f1 |
593 | |
4d583dd8 |
594 | # belongs_to(): |
595 | # args: |
596 | # 1) Name of relationship, DBIC will create accessor with this name |
597 | # 2) Name of the model class referenced by this relationship |
598 | # 3) Column name in *this* table |
599 | __PACKAGE__->belongs_to(author => 'MyAppDB::Author', 'author_id'); |
600 | |
601 | |
602 | =head1 NAME |
603 | |
604 | MyAppDB::BookAuthor - A model object representing the JOIN between an author and |
605 | a book. |
606 | |
607 | =head1 DESCRIPTION |
608 | |
609 | This is an object that represents a row in the 'book_authors' table of your |
610 | application database. It uses DBIx::Class (aka, DBIC) to do ORM. |
208513f1 |
611 | |
4d583dd8 |
612 | You probably won't need to use this class directly -- it will be automatically |
613 | used by DBIC where joins are needed. |
614 | |
615 | For Catalyst, this is designed to be used through MyApp::Model::MyAppDB. |
616 | Offline utilities may wish to use this class directly. |
617 | |
618 | =cut |
619 | |
620 | 1; |
621 | |
64ccd8a8 |
622 | B<Note:> This sample application uses a plural form for the database |
623 | tables (e.g., C<books> and C<authors>) and a singular form for the model |
624 | objects (e.g., C<Book> and C<Author>); however, Catalyst places no |
625 | restrictions on the naming conventions you wish to use. |
4d583dd8 |
626 | |
4d583dd8 |
627 | =head2 Use C<Catalyst::Model::DBIC::Schema> To Load The Model Class |
628 | |
14e6feb0 |
629 | When L<Catalyst::Model::DBIC::Schema|Catalyst::Model::DBIC::Schema> is |
64ccd8a8 |
630 | in use, Catalyst essentially reads an existing copy of your database |
631 | model and creates a new set of objects under C<MyApp::Model> for use |
632 | inside of Catalyst. |
4d583dd8 |
633 | |
14e6feb0 |
634 | B<Note:> With |
635 | L<Catalyst::Model::DBIC::Schema|Catalyst::Model::DBIC::Schema> you |
636 | essentially end up with two sets of model classes (only one of which |
637 | you write... the other set is created automatically in memory when |
638 | your Catalyst application initializes). For this tutorial application, |
639 | the important points to remember are: you write the I<result source> |
640 | files in C<MyAppDB>, but I<within Catalyst> you use the I<automatically |
641 | created model classes> in C<MyApp::Model>. |
4d583dd8 |
642 | |
14e6feb0 |
643 | Use the |
644 | L<Catalyst::Helper::Model::DBIC::Schema|Catalyst::Helper::Model::DBIC::Schema> |
645 | helper script to create the model class that loads up the model we |
646 | created in the previous step: |
4d583dd8 |
647 | |
648 | $ script/myapp_create.pl model MyAppDB DBIC::Schema MyAppDB dbi:SQLite:myapp.db '' '' '{ AutoCommit => 1 }' |
208513f1 |
649 | exists "/root/dev/MyApp/script/../lib/MyApp/Model" |
650 | exists "/root/dev/MyApp/script/../t" |
651 | created "/root/dev/MyApp/script/../lib/MyApp/Model/MyAppDB.pm" |
652 | created "/root/dev/MyApp/script/../t/model_MyAppDB.t" |
653 | |
4d583dd8 |
654 | |
64ccd8a8 |
655 | Where the first C<MyAppDB> is the name of the class to be created by the |
656 | helper in C<lib/MyApp/Model> and the second C<MyAppDB> is the name of |
657 | existing schema file we created (in C<lib/MyAppDB.pm>). You can see |
658 | that the helper creates a model file under C<lib/MyApp/Model> (Catalyst |
659 | has a separate directory under C<lib/MyApp> for each of the three parts |
660 | of MVC: C<Model>, C<View>, and C<Controller> [although older Catalyst |
661 | applications often use the directories C<M>, C<V>, and C<C>]). |
4d583dd8 |
662 | |
663 | |
4d583dd8 |
664 | =head1 CREATE A CATALYST CONTROLLER |
665 | |
71dedf57 |
666 | Controllers are where you write methods that interact with user |
667 | input--typically, controller methods respond to C<GET> and C<POST> |
668 | messages from the user's web browser. |
4d583dd8 |
669 | |
71dedf57 |
670 | Use the Catalyst C<create> script to add a controller for book-related |
671 | actions: |
4d583dd8 |
672 | |
673 | $ script/myapp_create.pl controller Books |
208513f1 |
674 | exists "/root/dev/MyApp/script/../lib/MyApp/Controller" |
675 | exists "/root/dev/MyApp/script/../t" |
676 | created "/root/dev/MyApp/script/../lib/MyApp/Controller/Books.pm" |
677 | created "/root/dev/MyApp/script/../t/controller_Books.t" |
4d583dd8 |
678 | |
64ccd8a8 |
679 | Then edit C<lib/MyApp/Controller/Books.pm> and add the following method |
680 | to the controller: |
4d583dd8 |
681 | |
682 | =head2 list |
683 | |
684 | Fetch all book objects and pass to books/list.tt2 in stash to be displayed |
685 | |
686 | =cut |
687 | |
688 | sub list : Local { |
689 | # Retrieve the usual perl OO '$self' for this object. $c is the Catalyst |
690 | # 'Context' that's used to 'glue together' the various components |
691 | # that make up the application |
692 | my ($self, $c) = @_; |
693 | |
694 | # Retrieve all of the book records as book model objects and store in the |
695 | # stash where they can be accessed by the TT template |
696 | $c->stash->{books} = [$c->model('MyAppDB::Book')->all]; |
697 | |
698 | # Set the TT template to use. You will almost always want to do this |
8112f931 |
699 | # in your action methods (actions methods respond to user input in |
700 | # your controllers). |
4d583dd8 |
701 | $c->stash->{template} = 'books/list.tt2'; |
702 | } |
703 | |
64ccd8a8 |
704 | B<Note:> Programmers experienced with object-oriented Perl should |
705 | recognize C<$self> as a reference to the object where this method was |
706 | called. On the other hand, C<$c> will be new to many Perl programmers |
707 | who have not used Catalyst before (it's sometimes written as |
708 | C<$context>). The Context object is automatically passed to all |
709 | Catalyst components. It is used to pass information between components |
710 | and provide access to Catalyst and plugin functionality. |
4d583dd8 |
711 | |
64ccd8a8 |
712 | B<TIP>: You may see the C<$c-E<gt>model('MyAppDB::Book')> used above |
713 | written as C<$c-E<gt>model('MyAppDB')-E<gt>resultset('Book)>. The two |
714 | are equivalent. |
4d583dd8 |
715 | |
64ccd8a8 |
716 | B<Note:> Catalyst actions are regular Perl methods, but they make use of |
14e6feb0 |
717 | Nicholas Clark's C<attributes> module (that's the C<: Local> next to the |
718 | C<sub list> in the code above) to provide additional information to the |
719 | Catalyst dispatcher logic. |
4d583dd8 |
720 | |
208513f1 |
721 | |
4d583dd8 |
722 | =head1 CATALYST VIEWS |
723 | |
71dedf57 |
724 | Views are where you render output, typically for display in the user's |
14e6feb0 |
725 | web browser, but also possibly using other display output-generation |
71dedf57 |
726 | systems. As with virtually every aspect of Catalyst, options abound |
727 | when it comes to the specific view technology you adopt inside your |
728 | application. However, most Catalyst applications use the Template |
729 | Toolkit, known as TT (for more information on TT, see |
208513f1 |
730 | L<http://www.template-toolkit.org>). Other popular view technologies |
71dedf57 |
731 | include Mason (L<http://www.masonhq.com> and |
14e6feb0 |
732 | L<http://www.masonbook.com>) and L<HTML::Template|HTML::Template> |
64ccd8a8 |
733 | (L<http://html-template.sourceforge.net>). |
4d583dd8 |
734 | |
70493af7 |
735 | =head2 Create a Catalyst View Using C<TTSite> |
4d583dd8 |
736 | |
737 | When using TT for the Catalyst view, there are two main helper scripts: |
738 | |
739 | =over 4 |
740 | |
741 | =item * |
742 | |
14e6feb0 |
743 | L<Catalyst::Helper::View::TT|Catalyst::Helper::View::TT> |
4d583dd8 |
744 | |
745 | =item * |
746 | |
14e6feb0 |
747 | L<Catalyst::Helper::View::TTSite|Catalyst::Helper::View::TTSite> |
4d583dd8 |
748 | |
749 | =back |
750 | |
64ccd8a8 |
751 | Both are similar, but C<TT> merely creates the C<lib/MyApp/View/TT.pm> |
752 | file and leaves the creation of any hierarchical template organization |
71dedf57 |
753 | entirely up to you. (It also creates a C<t/view_TT.t> file for testing; |
754 | test cases will be discussed in Part 7). The C<TTSite> helper creates a |
755 | modular and hierarchical view layout with separate Template Toolkit (TT) |
756 | files for common header and footer information, configuration values, a |
757 | CSS stylesheet, and more. |
4d583dd8 |
758 | |
64ccd8a8 |
759 | Enter the following command to enable the C<TTSite> style of view |
71dedf57 |
760 | rendering for this tutorial: |
4d583dd8 |
761 | |
762 | $ script/myapp_create.pl view TT TTSite |
208513f1 |
763 | exists "/root/dev/MyApp/script/../lib/MyApp/View" |
764 | exists "/root/dev/MyApp/script/../t" |
765 | created "/root/dev/MyApp/script/../lib/MyApp/View/TT.pm" |
766 | created "/root/dev/MyApp/script/../root/lib" |
767 | ... |
768 | created "/root/dev/MyApp/script/../root/src/ttsite.css" |
4d583dd8 |
769 | |
64ccd8a8 |
770 | This puts a number of files in the C<root/lib> and C<root/src> |
771 | directories that can be used to customize the look and feel of your |
772 | application. Also take a look at C<lib/MyApp/View/TT.pm> for config |
773 | values set by the C<TTSite> helper. |
774 | |
775 | B<TIP>: Note that TTSite does one thing that could confuse people who |
208513f1 |
776 | are used to the normal C<TT> Catalyst view: it redefines the Catalyst |
71dedf57 |
777 | context object in templates from its usual C<c> to C<Catalyst>. When |
778 | looking at other Catalyst examples, remember that they almost always use |
779 | C<c>. Note that Catalyst and TT I<do not complain> when you use the |
780 | wrong name to access the context object...TT simply outputs blanks for |
5c1f2a06 |
781 | that bogus logic (see next tip to change this behavior with TT C<DEBUG> |
782 | options). Finally, be aware that this change in name I<only> |
71dedf57 |
783 | applies to how the context object is accessed inside your TT templates; |
64ccd8a8 |
784 | your controllers will continue to use C<$c> (or whatever name you use |
71dedf57 |
785 | when fetching the reference from C<@_> inside your methods). (You can |
64ccd8a8 |
786 | change back to the "default" behavior be removing the C<CATALYST_VAR> |
787 | line from C<lib/MyApp/View/TT.pm>, but you will also have to edit |
788 | C<root/lib/config/main> and C<root/lib/config/url>. If you do this, be |
789 | careful not to have a collision between your own C<c> variable and the |
790 | Catalyst C<c> variable.) |
4d583dd8 |
791 | |
5c1f2a06 |
792 | B<TIP>: When troubleshooting TT it can be helpful to enable variable |
793 | C<DEBUG> options. You can do this in a Catalyst environment by adding |
794 | a C<DEBUG> line to the C<__PACKAGE__->config> declaration in |
8112f931 |
795 | C<lib/MyApp/View/TT.pm>: |
5c1f2a06 |
796 | |
797 | __PACKAGE__->config({ |
798 | CATALYST_VAR => 'Catalyst', |
799 | ... |
800 | DEBUG => 'undef', |
801 | ... |
802 | }); |
208513f1 |
803 | |
5c1f2a06 |
804 | There are a variety of options you can use, such as 'undef', 'all', |
805 | 'service', 'context', 'parser', 'provider', and 'service'. See |
806 | L<Template::Constants> for more information (remove the C<DEBUG_> |
807 | portion of the name shown in the TT docs and convert to lower case |
808 | for use inside Catalyst). |
809 | |
70493af7 |
810 | B<NOTE:> Please be sure to disable TT debug options before |
811 | continuing the tutorial (especially the 'undef' option -- leaving |
812 | this enabled will conflict with several of the conventions used |
813 | by this tutorial and TTSite to leave some variables undefined |
814 | on purpose). |
815 | |
5c1f2a06 |
816 | |
208513f1 |
817 | =head2 Using C<RenderView> for the Default View |
818 | |
819 | Once your controller logic has processed the request from a user, it |
820 | forwards processing to your view in order to generate the appropriate |
8e956464 |
821 | response output. Catalyst v5.7000 ships with a new mechanism, |
208513f1 |
822 | L<Catalyst::Action::RenderView|Catalyst::Action::RenderView>, that |
823 | automatically performs this operation. If you look in |
824 | C<lib/MyApp/Controller/Root.pm>, you should see the this empty |
825 | definition for the C<sub end> method: |
826 | |
827 | sub end : ActionClass('RenderView') {} |
828 | |
829 | The following bullet points provide a quick overview of the |
830 | C<RenderView> process: |
831 | |
832 | =over 4 |
833 | |
834 | =item * |
835 | |
836 | C<Root.pm> is designed to hold application-wide logic. |
837 | |
838 | =item * |
839 | |
840 | At the end of a given user request, Catalyst will call the most specific |
841 | C<end> method that's appropriate. For example, if the controller for a |
842 | request has an C<end> method defined, it will be called. However, if |
843 | the controller does not define a controller-specific C<end> method, the |
844 | "global" C<end> method in C<Root.pm> will be called. |
c608fae5 |
845 | |
208513f1 |
846 | =item * |
847 | |
848 | Because the definition includes an C<ActionClass> attribute, the |
849 | L<Catalyst::Action::RenderView|Catalyst::Action::RenderView> logic |
565d379b |
850 | will be executed B<after> any code inside the definition of C<sub end> |
208513f1 |
851 | is run. See L<Catalyst::Manual::Actions|Catalyst::Manual::Actions> |
852 | for more information on C<ActionClass>. |
853 | |
854 | =item * |
855 | |
856 | Because C<sub end> is empty, this effectively just runs the default |
857 | logic in C<RenderView>. However, you can easily extend the |
858 | C<RenderView> logic by adding your own code inside the empty method body |
859 | (C<{}>) created by the Catalyst Helpers when we first ran the |
860 | C<catalyst.pl> to initialize our application. See |
861 | L<Catalyst::Action::RenderView|Catalyst::Action::RenderView> for more |
862 | detailed information on how to extended C<RenderView> in C<sub end>. |
863 | |
864 | =back |
865 | |
866 | |
867 | =head3 The History Leading Up To C<RenderView> |
868 | |
869 | Although C<RenderView> strikes a nice balance between default |
870 | behavior and easy extensibility, it is a new feature that won't |
871 | appear in most existing Catalyst examples. This section provides |
872 | some brief background on the evolution of default view rendering |
873 | logic with an eye to how they can be migrated to C<RenderView>: |
c608fae5 |
874 | |
875 | =over 4 |
876 | |
877 | =item * |
878 | |
879 | Private C<end> Action in Application Class |
880 | |
881 | Older Catalyst-related documents often suggest that you add a "private |
882 | end action" to your application class (C<MyApp.pm>) or Root.pm |
883 | (C<MyApp/Controller/Root.pm>). These examples should be easily |
208513f1 |
884 | converted to L<RenderView|Catalyst::Action::RenderView> by simply adding |
8112f931 |
885 | the attribute C<:ActionClass('RenderView')> to the C<sub end> |
886 | definition. If end sub is defined in your application class |
887 | (C<MyApp.pm>), you should also migrate it to |
888 | C<MyApp/Controller/Root.pm>. |
c608fae5 |
889 | |
890 | =item * |
891 | |
892 | L<Catalyst::Plugin::DefaultEnd|Catalyst::Plugin::DefaultEnd> |
893 | |
208513f1 |
894 | C<DefaultEnd> represented the "next step" in passing processing from |
895 | your controller to your view. It has the advantage of only requiring |
896 | that C<DefaultEnd> be added to the list of plugins in C<lib/MyApp.pm>. |
897 | It also allowed you to add "dump_info=1" (precede with "?" or "&" |
898 | depending on where it is in the URL) to I<force> the debug screen at the |
899 | end of the Catalyst request processing cycle. However, it was more |
c9b77c06 |
900 | difficult to extend than the C<RenderView> mechanism, and is now |
901 | deprecated. |
c608fae5 |
902 | |
903 | =item * |
904 | |
905 | L<Catalyst::Action::RenderView|Catalyst::Action::RenderView> |
906 | |
208513f1 |
907 | As discussed above, the current recommended approach to handling your |
908 | view logic relies on |
c608fae5 |
909 | L<Catalyst::Action::RenderView|Catalyst::Action::RenderView>. Although |
208513f1 |
910 | similar in first appearance to the "private end action" approach, it |
911 | utilizes Catalyst's "ActionClass" mechanism to provide both automatic |
912 | default behavior (you don't have to include a plugin as with |
913 | C<DefaultEnd>) and easy extensibility. As with C<DefaultEnd>, it allows |
914 | you to add "dump_info=1" (precede with "?" or "&" depending on where it |
915 | is in the URL) to I<force> the debug screen at the end of the Catalyst |
916 | request processing cycle. |
c608fae5 |
917 | |
918 | =back |
919 | |
208513f1 |
920 | It is recommended that all Catalyst applications use or migrate to |
921 | the C<RenderView> approach. |
c608fae5 |
922 | |
923 | |
4d583dd8 |
924 | =head2 Globally Customize Every View |
925 | |
64ccd8a8 |
926 | When using TTSite, files in the subdirectories of C<root/lib> can be |
927 | used to make changes that will appear in every view. For example, to |
928 | display optional status and error messages in every view, edit |
71dedf57 |
929 | C<root/lib/site/layout>, updating it to match the following (the two HTML |
64ccd8a8 |
930 | C<span> elements are new): |
4d583dd8 |
931 | |
932 | <div id="header">[% PROCESS site/header %]</div> |
933 | |
934 | <div id="content"> |
935 | <span class="message">[% status_msg %]</span> |
936 | <span class="error">[% error_msg %]</span> |
937 | [% content %] |
938 | </div> |
939 | |
940 | <div id="footer">[% PROCESS site/footer %]</div> |
941 | |
64ccd8a8 |
942 | If we set either message in the Catalyst stash (e.g., |
71dedf57 |
943 | C<$c-E<gt>stash-E<gt>{status_msg} = 'Request was successful!'>) it will |
944 | be displayed whenever any view used by that request is rendered. The |
945 | C<message> and C<error> CSS styles are automatically defined in |
946 | C<root/src/ttsite.css> and can be customized to suit your needs. |
4d583dd8 |
947 | |
64ccd8a8 |
948 | B<Note:> The Catalyst stash only lasts for a single HTTP request. If |
949 | you need to retain information across requests you can use |
14e6feb0 |
950 | L<Catalyst::Plugin::Session|Catalyst::Plugin::Session> (we will use |
951 | Catalyst sessions in the Authentication part of the tutorial). |
4d583dd8 |
952 | |
953 | |
954 | =head2 Create a TT Template Page |
955 | |
64ccd8a8 |
956 | To add a new page of content to the TTSite view hierarchy, just create a |
957 | new C<.tt2> file in C<root/src>. Only include HTML markup that goes |
958 | inside the HTML <body> and </body> tags, TTSite will use the contents of |
959 | C<root/lib/site> to add the top and bottom. |
4d583dd8 |
960 | |
961 | First create a directory for book-related TT templates: |
962 | |
963 | $ mkdir root/src/books |
964 | |
965 | Then open C<root/src/books/list.tt2> in your editor and enter: |
966 | |
967 | [% # This is a TT comment. The '-' at the end "chomps" the newline. You won't -%] |
968 | [% # see this "chomping" in your browser because HTML ignores blank lines, but -%] |
969 | [% # it WILL eliminate a blank line if you view the HTML source. It's purely -%] |
970 | [%- # optional, but both the beginning and the ending TT tags support chomping. -%] |
971 | |
972 | [% # Provide a title to root/lib/site/header -%] |
973 | [% META title = 'Book List' -%] |
974 | |
975 | <table> |
976 | <tr><th>Title</th><th>Rating</th><th>Author(s)</th></tr> |
977 | [% # Display each book in a table row %] |
978 | [% FOREACH book IN books -%] |
979 | <tr> |
980 | <td>[% book.title %]</td> |
981 | <td>[% book.rating %]</td> |
982 | <td> |
14e6feb0 |
983 | [% # First initialize a TT variable to hold a list. Then use a TT FOREACH -%] |
984 | [% # loop in 'side effect notation' to load just the last names of the -%] |
c9b77c06 |
985 | [% # authors into the list. Note that the 'push' TT vmethod does not -%] |
986 | [% # a value, so nothing will be printed here. But, if you have something -%] |
987 | [% # in TT that does return a method and you don't want it printed, you -%] |
988 | [% # can: 1) assign it to a bogus value, or 2) use the CALL keyword to -%] |
989 | [% # call it and discard the return value. -%] |
14e6feb0 |
990 | [% tt_authors = [ ]; |
c9b77c06 |
991 | tt_authors.push(author.last_name) FOREACH author = book.authors %] |
14e6feb0 |
992 | [% # Now use a TT 'virtual method' to display the author count in parens -%] |
993 | ([% tt_authors.size %]) |
c9b77c06 |
994 | [% # Use another TT vmethod to join & print the names & comma separators -%] |
14e6feb0 |
995 | [% tt_authors.join(', ') %] |
4d583dd8 |
996 | </td> |
997 | </tr> |
998 | [% END -%] |
999 | </table> |
1000 | |
64ccd8a8 |
1001 | As indicated by the inline comments above, the C<META title> line uses |
1002 | TT's META feature to provide a title to C<root/lib/site/header>. |
1003 | Meanwhile, the outer C<FOREACH> loop iterates through each C<book> model |
1004 | object and prints the C<title> and C<rating> fields. An inner |
14e6feb0 |
1005 | C<FOREACH> loop prints the last name of each author in a comma-separated |
1006 | list within a single table cell. |
64ccd8a8 |
1007 | |
71dedf57 |
1008 | If you are new to TT, the C<[%> and C<%]> tags are used to delimit TT |
1009 | code. TT supports a wide variety of directives for "calling" other |
64ccd8a8 |
1010 | files, looping, conditional logic, etc. In general, TT simplifies the |
1011 | usual range of Perl operators down to the single dot (C<.>) operator. |
1012 | This applies to operations as diverse as method calls, hash lookups, and |
1013 | list index values (see |
1014 | L<http://www.template-toolkit.org/docs/default/Manual/Variables.html> |
1015 | for details and examples). In addition to the usual C<Template> module |
1016 | Pod documentation, you can access the TT manual at |
1017 | L<http://www.template-toolkit.org/docs/default/>. |
1018 | |
1019 | B<NOTE>: The C<TTSite> helper creates several TT files using an |
1020 | extension of C<.tt2>. Most other Catalyst and TT examples use an |
1021 | extension of C<.tt>. You can use either extension (or no extension at |
1022 | all) with TTSite and TT, just be sure to use the appropriate extension |
1023 | for both the file itself I<and> the C<$c-E<gt>stash-E<gt>{template} = |
1024 | ...> line in your controller. This document will use C<.tt2> for |
1025 | consistency with the files already created by the C<TTSite> helper. |
4d583dd8 |
1026 | |
1027 | |
4d583dd8 |
1028 | =head1 RUN THE APPLICATION |
1029 | |
64ccd8a8 |
1030 | First, let's enable an environment variable option that causes |
1031 | DBIx::Class to dump the SQL statements it's using to access the database |
1032 | (this option can provide extremely helpful troubleshooting information): |
4d583dd8 |
1033 | |
1034 | $ export DBIX_CLASS_STORAGE_DBI_DEBUG=1 |
1035 | |
cc548726 |
1036 | This assumes you are using BASH as your shell -- adjust accordingly if |
1037 | you are using a different shell (for example, under tcsh, use |
1038 | C<setenv DBIX_CLASS_STORAGE_DBI_DEBUG 1>). |
1039 | |
64ccd8a8 |
1040 | B<NOTE>: You can also set this in your code using |
1041 | C<$class-E<gt>storage-E<gt>debug(1);>. See |
71dedf57 |
1042 | L<DBIx::Class::Manual::Troubleshooting> for details (including options |
1043 | to log to file instead of displaying to the Catalyst development server |
1044 | log). |
4d583dd8 |
1045 | |
1046 | Then run the Catalyst "demo server" script: |
1047 | |
1048 | $ script/myapp_server.pl |
1049 | |
208513f1 |
1050 | Your development server log output should display something like: |
4d583dd8 |
1051 | |
1052 | $ script/myapp_server.pl |
208513f1 |
1053 | [debug] Debug messages enabled |
1054 | [debug] Loaded plugins: |
1055 | .----------------------------------------------------------------------------. |
1056 | | Catalyst::Plugin::ConfigLoader 0.06 | |
1057 | | Catalyst::Plugin::StackTrace 0.04 | |
1058 | | Catalyst::Plugin::Static::Simple 0.14 | |
1059 | '----------------------------------------------------------------------------' |
4d583dd8 |
1060 | |
208513f1 |
1061 | [debug] Loaded dispatcher "Catalyst::Dispatcher" |
1062 | [debug] Loaded engine "Catalyst::Engine::HTTP" |
1063 | [debug] Found home "/home/me/MyApp" |
1064 | [debug] Loaded components: |
1065 | .-----------------------------------------------------------------+----------. |
1066 | | Class | Type | |
1067 | +-----------------------------------------------------------------+----------+ |
1068 | | MyApp::Controller::Books | instance | |
1069 | | MyApp::Controller::Root | instance | |
1070 | | MyApp::Model::MyAppDB | instance | |
1071 | | MyApp::Model::MyAppDB::Author | class | |
1072 | | MyApp::Model::MyAppDB::Book | class | |
1073 | | MyApp::Model::MyAppDB::BookAuthor | class | |
1074 | | MyApp::View::TT | instance | |
1075 | '-----------------------------------------------------------------+----------' |
4d583dd8 |
1076 | |
208513f1 |
1077 | [debug] Loaded Private actions: |
1078 | .----------------------+--------------------------------------+--------------. |
1079 | | Private | Class | Method | |
1080 | +----------------------+--------------------------------------+--------------+ |
1081 | | /default | MyApp::Controller::Root | default | |
1082 | | /end | MyApp::Controller::Root | end | |
1083 | | /books/index | MyApp::Controller::Books | index | |
1084 | | /books/list | MyApp::Controller::Books | list | |
1085 | '----------------------+--------------------------------------+--------------' |
4d583dd8 |
1086 | |
208513f1 |
1087 | [debug] Loaded Path actions: |
1088 | .-------------------------------------+--------------------------------------. |
1089 | | Path | Private | |
1090 | +-------------------------------------+--------------------------------------+ |
1091 | | /books/list | /books/list | |
1092 | '-------------------------------------+--------------------------------------' |
4d583dd8 |
1093 | |
8e956464 |
1094 | [info] MyApp powered by Catalyst 5.7000 |
208513f1 |
1095 | You can connect to your server at http://localhost.localdomain:3000 |
4d583dd8 |
1096 | |
1097 | Some things you should note in the output above: |
1098 | |
1099 | =over 4 |
1100 | |
1101 | =item * |
1102 | |
64ccd8a8 |
1103 | Catalyst::Model::DBIC::Schema took our C<MyAppDB::Book> and made it |
1104 | C<MyApp::Model::MyAppDB::Book> (and similar actions were performed on |
1105 | C<MyAppDB::Author> and C<MyAppDB::BookAuthor>). |
4d583dd8 |
1106 | |
1107 | =item * |
1108 | |
64ccd8a8 |
1109 | The "list" action in our Books controller showed up with a path of |
1110 | C</books/list>. |
4d583dd8 |
1111 | |
1112 | =back |
1113 | |
64ccd8a8 |
1114 | Point your browser to L<http://localhost:3000> and you should still get |
1115 | the Catalyst welcome page. |
4d583dd8 |
1116 | |
64ccd8a8 |
1117 | Next, to view the book list, change the URL in your browser to |
1118 | L<http://localhost:3000/books/list>. You should get a list of the five |
1119 | books loaded by the C<myapp01.sql> script above, with TTSite providing |
1120 | the formatting for the very simple output we generated in our template. |
1121 | The count and space-separated list of author last names appear on the |
1122 | end of each row. |
4d583dd8 |
1123 | |
64ccd8a8 |
1124 | Also notice in the output of the C<script/myapp_server.pl> that DBIC |
1125 | used the following SQL to retrieve the data: |
4d583dd8 |
1126 | |
1127 | SELECT me.id, me.title, me.rating FROM books me |
1128 | |
64ccd8a8 |
1129 | Along with a list of the following commands to retrieve the authors for |
1130 | each book (the lines have been "word wrapped" here to improve |
1131 | legibility): |
4d583dd8 |
1132 | |
1133 | SELECT author.id, author.first_name, author.last_name |
1134 | FROM book_authors me |
1135 | JOIN authors author ON ( author.id = me.author_id ) |
1136 | WHERE ( me.book_id = ? ): `1' |
1137 | |
208513f1 |
1138 | You should see 5 such lines of debug output as DBIC fetches the author |
1139 | information for each book. |
4d583dd8 |
1140 | |
1141 | |
1142 | =head1 AUTHOR |
1143 | |
1144 | Kennedy Clark, C<hkclark@gmail.com> |
1145 | |
c608fae5 |
1146 | Please report any errors, issues or suggestions to the author. The |
7d310f12 |
1147 | most recent version of the Catalyst Tutorial can be found at |
c608fae5 |
1148 | L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Runtime/lib/Catalyst/Manual/Tutorial/>. |
4d583dd8 |
1149 | |
71dedf57 |
1150 | Copyright 2006, Kennedy Clark, under Creative Commons License |
1151 | (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>). |
4d583dd8 |
1152 | |