1Catalyst::View::TT(3) User Contributed Perl DocumentationCatalyst::View::TT(3)
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NAME

6       Catalyst::View::TT - Template View Class
7

SYNOPSIS

9       # use the helper to create your View
10
11           myapp_create.pl view Web TT
12
13       # add custom configuration in View/Web.pm
14
15           __PACKAGE__->config(
16               # any TT configuration items go here
17               TEMPLATE_EXTENSION => '.tt',
18               CATALYST_VAR => 'c',
19               TIMER        => 0,
20               ENCODING     => 'utf-8'
21               # Not set by default
22               PRE_PROCESS        => 'config/main',
23               WRAPPER            => 'site/wrapper',
24               render_die => 1, # Default for new apps, see render method docs
25               expose_methods => [qw/method_in_view_class/],
26           );
27
28       # add include path configuration in MyApp.pm
29
30           __PACKAGE__->config(
31               'View::Web' => {
32                   INCLUDE_PATH => [
33                       __PACKAGE__->path_to( 'root', 'src' ),
34                       __PACKAGE__->path_to( 'root', 'lib' ),
35                   ],
36               },
37           );
38
39       # render view from lib/MyApp.pm or
40       lib/MyApp::Controller::SomeController.pm
41
42           sub message : Global {
43               my ( $self, $c ) = @_;
44               $c->stash->{template} = 'message.tt2';
45               $c->stash->{message}  = 'Hello World!';
46               $c->forward( $c->view('Web') );
47           }
48
49       # access variables from template
50
51           The message is: [% message %].
52
53           # example when CATALYST_VAR is set to 'Catalyst'
54           Context is [% Catalyst %]
55           The base is [% Catalyst.req.base %]
56           The name is [% Catalyst.config.name %]
57
58           # example when CATALYST_VAR isn't set
59           Context is [% c %]
60           The base is [% base %]
61           The name is [% name %]
62

DESCRIPTION

64       This is the Catalyst view class for the Template Toolkit.  Your
65       application should defined a view class which is a subclass of this
66       module. Throughout this manual it will be assumed that your application
67       is named MyApp and you are creating a TT view named Web; these names
68       are placeholders and should always be replaced with whatever name
69       you've chosen for your application and your view. The easiest way to
70       create a TT view class is through the myapp_create.pl script that is
71       created along with the application:
72
73           $ script/myapp_create.pl view Web TT
74
75       This creates a MyApp::View::Web.pm module in the lib directory (again,
76       replacing "MyApp" with the name of your application) which looks
77       something like this:
78
79           package FooBar::View::Web;
80           use Moose;
81
82           extends 'Catalyst::View::TT';
83
84           __PACKAGE__->config(DEBUG => 'all');
85
86       Now you can modify your action handlers in the main application and/or
87       controllers to forward to your view class.  You might choose to do this
88       in the end() method, for example, to automatically forward all actions
89       to the TT view class.
90
91           # In MyApp or MyApp::Controller::SomeController
92
93           sub end : Private {
94               my( $self, $c ) = @_;
95               $c->forward( $c->view('Web') );
96           }
97
98       But if you are using the standard auto-generated end action, you don't
99       even need to do this!
100
101           # in MyApp::Controller::Root
102           sub end : ActionClass('RenderView') {} # no need to change this line
103
104           # in MyApp.pm
105           __PACKAGE__->config(
106               ...
107               default_view => 'Web',
108           );
109
110       This will Just Work.  And it has the advantages that:
111
112       •   If you want to use a different view for a given request, just set
113           << $c->stash->{current_view} >>.  (See Catalyst's "$c->view" method
114           for details.
115
116       •   << $c->res->redirect >> is handled by default.  If you just forward
117           to "View::Web" in your "end" routine, you could break this by
118           sending additional content.
119
120       See Catalyst::Action::RenderView for more details.
121
122   CONFIGURATION
123       There are a three different ways to configure your view class.  The
124       first way is to call the config() method in the view subclass.  This
125       happens when the module is first loaded.
126
127           package MyApp::View::Web;
128           use Moose;
129           extends 'Catalyst::View::TT';
130
131           __PACKAGE__->config({
132               PRE_PROCESS  => 'config/main',
133               WRAPPER      => 'site/wrapper',
134           });
135
136       You may also override the configuration provided in the view class by
137       adding a 'View::Web' section to your application config.
138
139       This should generally be used to inject the include paths into the view
140       to avoid the view trying to load the application to resolve paths.
141
142           .. inside MyApp.pm ..
143           __PACKAGE__->config(
144               'View::Web' => {
145                   INCLUDE_PATH => [
146                       __PACKAGE__->path_to( 'root', 'templates', 'lib' ),
147                       __PACKAGE__->path_to( 'root', 'templates', 'src' ),
148                   ],
149               },
150           );
151
152       You can also configure your view from within your config file if you're
153       using Catalyst::Plugin::ConfigLoader. This should be reserved for
154       deployment-specific concerns. For example:
155
156           # MyApp_local.conf (Config::General format)
157
158           <View Web>
159             WRAPPER "custom_wrapper"
160             INCLUDE_PATH __path_to('root/templates/custom_site')__
161             INCLUDE_PATH __path_to('root/templates')__
162           </View>
163
164       might be used as part of a simple way to deploy different instances of
165       the same application with different themes.
166
167   DYNAMIC INCLUDE_PATH
168       Sometimes it is desirable to modify INCLUDE_PATH for your templates at
169       run time.
170
171       Additional paths can be added to the start of INCLUDE_PATH via the
172       stash as follows:
173
174           $c->stash->{additional_template_paths} =
175               [$c->config->{root} . '/test_include_path'];
176
177       If you need to add paths to the end of INCLUDE_PATH, there is also an
178       include_path() accessor available:
179
180           push( @{ $c->view('Web')->include_path }, qw/path/ );
181
182       Note that if you use include_path() to add extra paths to INCLUDE_PATH,
183       you MUST check for duplicate paths. Without such checking, the above
184       code will add "path" to INCLUDE_PATH at every request, causing a memory
185       leak.
186
187       A safer approach is to use include_path() to overwrite the array of
188       paths rather than adding to it. This eliminates both the need to
189       perform duplicate checking and the chance of a memory leak:
190
191           @{ $c->view('Web')->include_path } = qw/path another_path/;
192
193       If you are calling "render" directly then you can specify dynamic paths
194       by having a "additional_template_paths" key with a value of additional
195       directories to search. See "CAPTURING TEMPLATE OUTPUT" for an example
196       showing this.
197
198   Unicode (pre Catalyst v5.90080)
199       NOTE Starting with Catalyst v5.90080 unicode and encoding has been
200       baked into core, and the default encoding is UTF-8.  The following
201       advice is for older versions of Catalyst.
202
203       Be sure to set "ENCODING => 'utf-8'" and use
204       Catalyst::Plugin::Unicode::Encoding if you want to use non-ascii
205       characters (encoded as utf-8) in your templates.  This is only needed
206       if you actually have UTF8 literals in your templates and the BOM is not
207       properly set.  Setting encoding here does not magically encode your
208       template output.  If you are using this version of Catalyst you need to
209       all the Unicode plugin, or upgrade (preferred)
210
211   Unicode (Catalyst v5.90080+)
212       This version of Catalyst will automatically encode your body output to
213       UTF8. This means if your variables contain multibyte characters you
214       don't need top do anything else to get UTF8 output.  However if your
215       templates contain UTF8 literals (like, multibyte characters actually in
216       the template text), then you do need to either set the BOM mark on the
217       template file or instruct TT to decode the templates at load time via
218       the ENCODING configuration setting.  Most of the time you can just do:
219
220           MyApp::View::HTML->config(
221               ENCODING => 'UTF-8');
222
223       and that will just take care of everything.  This configuration setting
224       will force Template to decode all files correctly, so that when you hit
225       the finalize_encoding step we can properly encode the body as UTF8.  If
226       you fail to do this you will get double encoding issues in your output
227       (but again, only for the UTF8 literals in your actual template text.)
228
229       Again, this ENCODING configuration setting only instructs template
230       toolkit how (and if) to decode the contents of your template files when
231       reading them from disk.  It has no other effect.
232
233   RENDERING VIEWS
234       The view plugin renders the template specified in the "template" item
235       in the stash.
236
237           sub message : Global {
238               my ( $self, $c ) = @_;
239               $c->stash->{template} = 'message.tt2';
240               $c->forward( $c->view('Web') );
241           }
242
243       If a stash item isn't defined, then it instead uses the stringification
244       of the action dispatched to (as defined by $c->action) in the above
245       example, this would be "message", but because the default is to append
246       '.tt', it would load "root/message.tt".
247
248       The items defined in the stash are passed to the Template Toolkit for
249       use as template variables.
250
251           sub default : Private {
252               my ( $self, $c ) = @_;
253               $c->stash->{template} = 'message.tt2';
254               $c->stash->{message}  = 'Hello World!';
255               $c->forward( $c->view('Web') );
256           }
257
258       A number of other template variables are also added:
259
260           c      A reference to the context object, $c
261           base   The URL base, from $c->req->base()
262           name   The application name, from $c->config->{ name }
263
264       These can be accessed from the template in the usual way:
265
266       <message.tt2>:
267
268           The message is: [% message %]
269           The base is [% base %]
270           The name is [% name %]
271
272       The output generated by the template is stored in "$c->response->body".
273
274   CAPTURING TEMPLATE OUTPUT
275       If you wish to use the output of a template for some other purpose than
276       displaying in the response, e.g. for sending an email, this is possible
277       using other views, such as Catalyst::View::Email::Template.
278
279   TEMPLATE PROFILING
280       See ""TIMER"" property of the "config" method.
281

METHODS

283   new
284       The constructor for the TT view. Sets up the template provider, and
285       reads the application config.
286
287   process($c)
288       Renders the template specified in "$c->stash->{template}" or
289       "$c->action" (the private name of the matched action).  Calls render to
290       perform actual rendering. Output is stored in "$c->response->body".
291
292       It is possible to forward to the process method of a TT view from
293       inside Catalyst like this:
294
295           $c->forward('View::Web');
296
297       N.B. This is usually done automatically by
298       Catalyst::Action::RenderView.
299
300   render($c, $template, \%args)
301       Renders the given template and returns output. Throws a
302       Template::Exception object upon error.
303
304       The template variables are set to %$args if $args is a hashref, or
305       "$c->stash" otherwise. In either case the variables are augmented with
306       "base" set to "$c->req->base", "c" to $c, and "name" to
307       "$c->config->{name}". Alternately, the "CATALYST_VAR" configuration
308       item can be defined to specify the name of a template variable through
309       which the context reference ($c) can be accessed. In this case, the
310       "c", "base", and "name" variables are omitted.
311
312       $template can be anything that Template::process understands how to
313       process, including the name of a template file or a reference to a test
314       string.  See Template::process for a full list of supported formats.
315
316       To use the render method outside of your Catalyst app, just pass a
317       undef context.  This can be useful for tests, for instance.
318
319       It is possible to forward to the render method of a TT view from inside
320       Catalyst to render page fragments like this:
321
322           my $fragment = $c->forward("View::Web", "render", $template_name, $c->stash->{fragment_data});
323
324       Backwards compatibility note
325
326       The render method used to just return the Template::Exception object,
327       rather than just throwing it. This is now deprecated and instead the
328       render method will throw an exception for new applications.
329
330       This behaviour can be activated (and is activated in the default
331       skeleton configuration) by using "render_die => 1". If you rely on the
332       legacy behaviour then a warning will be issued.
333
334       To silence this warning, set "render_die => 0", but it is recommended
335       you adjust your code so that it works with "render_die => 1".
336
337       In a future release, "render_die => 1" will become the default if
338       unspecified.
339
340   template_vars
341       Returns a list of keys/values to be used as the catalyst variables in
342       the template.
343
344   config
345       This method allows your view subclass to pass additional settings to
346       the TT configuration hash, or to set the options as below:
347
348   paths
349       The list of paths TT will look for templates in.
350
351   expose_methods
352       The list of methods in your View class which should be made available
353       to the templates.
354
355       For example:
356
357         expose_methods => [qw/uri_for_css/],
358
359         ...
360
361         sub uri_for_css {
362           my ($self, $c, $filename) = @_;
363
364           # additional complexity like checking file exists here
365
366           return $c->uri_for('/static/css/' . $filename);
367         }
368
369       Then in the template:
370
371         [% uri_for_css('home.css') %]
372
373   content_type
374       This lets you override the default content type for the response.  If
375       you do not set this and if you do not set the content type in your
376       controllers, the default is "text/html; charset=utf-8".
377
378       Use this if you are creating alternative view responses, such as text
379       or JSON and want a global setting.
380
381       Any content type set in your controllers before calling this view are
382       respected and have priority.
383
384   "CATALYST_VAR"
385       Allows you to change the name of the Catalyst context object. If set,
386       it will also remove the base and name aliases, so you will have access
387       them through <context>.
388
389       For example, if CATALYST_VAR has been set to "Catalyst", a template
390       might contain:
391
392           The base is [% Catalyst.req.base %]
393           The name is [% Catalyst.config.name %]
394
395   "TIMER"
396       If you have configured Catalyst for debug output, and turned on the
397       TIMER setting, "Catalyst::View::TT" will enable profiling of template
398       processing (using Template::Timer). This will embed HTML comments in
399       the output from your templates, such as:
400
401           <!-- TIMER START: process mainmenu/mainmenu.ttml -->
402           <!-- TIMER START: include mainmenu/cssindex.tt -->
403           <!-- TIMER START: process mainmenu/cssindex.tt -->
404           <!-- TIMER END: process mainmenu/cssindex.tt (0.017279 seconds) -->
405           <!-- TIMER END: include mainmenu/cssindex.tt (0.017401 seconds) -->
406
407           ....
408
409           <!-- TIMER END: process mainmenu/footer.tt (0.003016 seconds) -->
410
411   "TEMPLATE_EXTENSION"
412       a suffix to add when looking for templates bases on the "match" method
413       in Catalyst::Request.
414
415       For example:
416
417         package MyApp::Controller::Test;
418         sub test : Local { .. }
419
420       Would by default look for a template in <root>/test/test. If you set
421       TEMPLATE_EXTENSION to '.tt', it will look for <root>/test/test.tt.
422
423   "PROVIDERS"
424       Allows you to specify the template providers that TT will use.
425
426           MyApp->config(
427               name     => 'MyApp',
428               root     => MyApp->path_to('root'),
429               'View::Web' => {
430                   PROVIDERS => [
431                       {
432                           name    => 'DBI',
433                           args    => {
434                               DBI_DSN => 'dbi:DB2:books',
435                               DBI_USER=> 'foo'
436                           }
437                       }, {
438                           name    => '_file_',
439                           args    => {}
440                       }
441                   ]
442               },
443           );
444
445       The 'name' key should correspond to the class name of the provider you
446       want to use.  The _file_ name is a special case that represents the
447       default TT file-based provider.  By default the name is will be
448       prefixed with 'Template::Provider::'.  You can fully qualify the name
449       by using a unary plus:
450
451           name => '+MyApp::Provider::Foo'
452
453       You can also specify the 'copy_config' key as an arrayref, to copy
454       those keys from the general config, into the config for the provider:
455
456           DEFAULT_ENCODING    => 'utf-8',
457           PROVIDERS => [
458               {
459                   name    => 'Encoding',
460                   copy_config => [qw(DEFAULT_ENCODING INCLUDE_PATH)]
461               }
462           ]
463
464       This can prove useful when you want to use the
465       additional_template_paths hack in your own provider, or if you need to
466       use Template::Provider::Encoding
467
468   "CLASS"
469       Allows you to specify a custom class to use as the template class
470       instead of Template.
471
472           package MyApp::View::Web;
473           use Moose;
474           extends 'Catalyst::View::TT';
475
476           use Template::AutoFilter;
477
478           __PACKAGE__->config({
479               CLASS => 'Template::AutoFilter',
480           });
481
482       This is useful if you want to use your own subclasses of Template, so
483       you can, for example, prevent XSS by automatically filtering all output
484       through "| html".
485
486   HELPERS
487       The Catalyst::Helper::View::TT and Catalyst::Helper::View::TTSite
488       helper modules are provided to create your view module.  There are
489       invoked by the myapp_create.pl script:
490
491           $ script/myapp_create.pl view Web TT
492
493           $ script/myapp_create.pl view Web TTSite
494
495       The Catalyst::Helper::View::TT module creates a basic TT view module.
496       The Catalyst::Helper::View::TTSite module goes a little further.  It
497       also creates a default set of templates to get you started.  It also
498       configures the view module to locate the templates automatically.
499

NOTES

501       If you are using the CGI module inside your templates, you will
502       experience that the Catalyst server appears to hang while rendering the
503       web page. This is due to the debug mode of CGI (which is waiting for
504       input in the terminal window). Turning off the debug mode using the
505       "-no_debug" option solves the problem, eg.:
506
507           [% USE CGI('-no_debug') %]
508

SEE ALSO

510       Catalyst, Catalyst::Helper::View::TT, Catalyst::Helper::View::TTSite,
511       Template::Manual
512

AUTHORS

514       Sebastian Riedel, "sri@cpan.org"
515
516       Marcus Ramberg, "mramberg@cpan.org"
517
518       Jesse Sheidlower, "jester@panix.com"
519
520       Andy Wardley, "abw@cpan.org"
521
522       Luke Saunders, "luke.saunders@gmail.com"
523
525       This program is free software. You can redistribute it and/or modify it
526       under the same terms as Perl itself.
527
528
529
530perl v5.38.0                      2023-07-20             Catalyst::View::TT(3)
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