1Template::FAQ(3) User Contributed Perl Documentation Template::FAQ(3)
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6 Template::FAQ - Frequently Asked Questions about the Template Toolkit
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9 Why doesn't [% a = b IF c %] work as expected?
10 There's a limitation in the TT2 parser which means that the following
11 code doesn't work as you might expect:
12 [% a = b IF c %]
14 The parser interprets it as an attempt to set "a" to the result of "b
16 IF c", like this:
17 [% a = (b IF c) %]
19 If you want to set "a = b" only if "c" is true, then do this instead:
21 [% SET a = b IF c %]
23 The explicit "SET" keyword gives the parser the clue it needs to do the
25 right thing.
26 NOTE: this will be fixed in TT3
28 If I'm using TT to write out a TT template, is there a good way to escape
30 [% and %]?
31 You can do something like this:
32 [% stag = "[\%"
34 etag = "%\]"
35 %]
36 and then:
38 [% stag; 'hello'; etag %]
40 Or you can use the "TAGS" directive, like so:
42 [% TAGS [- -] %]
44 [- INCLUDE foo -] # is a directive
45 [% INCLUDE foo %] # not a directive
46 How do I iterate over a hash?
48 This is covered in the Template::Manual::VMethods section of the
49 manual. A list of all the keys that are in the hash can be obtained
50 with the "keys" virtual method. You can then iterate over that list and
51 by looking up each key in turn get the value.
52 [% FOREACH key = product.keys %]
54 [% key %] => [% product.$key %]
55 [% END %]
56
58 How do I get the Table plugin to order data across rather than down?
59 Order the data into rows:
60 Steve Karen Jeff
62 Brooklyn Nantucket Fairfax
63 NY MA VA
64 [% USE table(data, rows=3) %]
66 Then ask for each column
68 [% FOREACH column = table.cols %]
70 And then print each item in the column going across the output rows
72 [% FOREACH item = column %]
74 <td>[% item %]</td>
75 [% END %]
76 Accessing Cookies
78 Jeff Boes <jboes@nexcerpt.com> asks:
79 Does anyone have a quick-n-dirty approach to accessing
81 cookies from templates?
82 Jonas Liljegren answers:
84 [% USE CGI %]
86 <p>The value is [% CGI.cookie('cookie_name') | html %]
88
90 Can I serve templates from a database?
91 Short answer: yes, Chris Nandor has done this for Slash. You need to
92 subclass Template::Provider. See the mailing list archives for further
93 info.
94 Can I fetch templates via http?
96 To do the job properly, you should subclass Template::Provider to
97 "Template::Provider::HTTP" and use a "PREFIX_MAP" option to bind the
98 "http" template prefix to that particular provider (you may want to go
99 digging around in the Changes file around version 2.01 for more info on
100 "PREFIX_MAP" - it may not be properly documented anywhere else...yet!).
101 e.g.
102 use Template::Provider::HTTP;
104 my $file = Template::Provider( INCLUDE_PATH => [...] );
106 my $http = Template::Provider::HTTP->new(...);
107 my $tt2 = Template->new({
108 LOAD_TEMPLATES => [ $file, $http ],
109 PREFIX_MAP => {
110 file => '0', # file:foo.html
111 http => '1', # http:foo.html
112 default => '0', # foo.html => file:foo.html
113 }
114 });
115 Now a template specified as:
117 [% INCLUDE foo %]
119 will be served by the 'file' provider (the default). Otherwise you can
121 explicitly add a prefix:
122 [% INCLUDE file:foo.html %]
124 [% INCLUDE http:foo.html %]
125 [% INCLUDE http://www.xyz.com/tt2/header.tt2 %]
126 This same principal can be used to create a DBI template provider.
128 e.g.
129 [% INCLUDE dbi:foo.html %]
131 Alas, we don't yet have a DBI provider as part of the Template Toolkit.
133 There has been some talk on the mailing list about efforts to develop
134 DBI and/or HTTP providers but as yet no-one has stepped forward to take
135 up the challenge...
136 In the mean time, Craig Barrat's post from the mailing list has some
138 useful pointers on how to achieve this using existing modules. See
139 http://tt2.org/pipermail/templates/2001-May/000954.html
140 <http://tt2.org/pipermail/templates/2001-May/000954.html>
141
143 How can I find out the name of the main template being processed?
144 The "template" variable contains a reference to the Template::Document
145 object for the main template you're processing (i.e. the one provided
146 as the first argument to the Template process() method). The "name"
147 method returns its name.
148 [% template.name %] # e.g. index.html
150 How can I find out the name of the current template being processed?
152 The "template" variable always references the main template being
153 processed. So even if you call [% INCLUDE header %], and that calls [%
154 INCLUDE menu %], the "template" variable will be unchanged.
155 index.html:
157 [% template.name %] # index.html
159 [% INCLUDE header %]
160 header:
162 [% template.name %] # index.html
164 [% INCLUDE menu %]
165 menu:
167 [% template.name %] # index.html
169 In constrast, the "component" variable always references the current
171 template being processed.
172 index.html
174 [% component.name %] # index.html
176 [% INCLUDE header %]
177 header:
179 [% component.name %] # header
181 [% INCLUDE menu %]
182 menu:
184 [% component.name %] # menu
186 How do I print the modification time of the template or component?
188 The "template" and "component" variables reference the main template
189 and the current template being processed (see previous questions). The
190 "modtime" method returns the modification time of the corresponding
191 template file as a number of seconds since the Unix epoch (00:00:00 GMT
192 1st January 1970).
193 This number doesn't mean much to anyone (except perhaps serious Unix
195 geeks) so you'll probably want to use the Date plugin to format it for
196 human consumption.
197 [% USE Date %]
199 [% template.name %] last modified [% Date.format(template.modtime) %]
200 How can I configure variables on a per-request basis?
202 One easy way to achieve this is to define a single "PRE_PROCESS"
203 template which loads in other configuration files based on variables
204 defined or other conditions.
205 For example, my setup usually looks something like this:
207 PRE_PROCESS => 'config/main'
209 config/main:
211 [% DEFAULT style = 'text'
213 section = template.section or 'home';
214 PROCESS config/site
216 + config/urls
217 + config/macros
218 + "config/style/$style"
219 + "config/section/$section"
220 + ...
221 %]
222 This allows me to set a single 'style' variable to control which config
224 file gets pre-processed to set my various style options (colours, img
225 paths, etc). For example:
226 config/style/basic:
228 [% style = {
230 name = style # save existing 'style' var as 'style.name'
231 # define various other style variables....
233 col = {
234 back => '#ffffff'
235 text => '#000000'
236 # ...etc...
237 }
238 logo = {
240 # ...etc...
241 }
242 # ...etc...
244 }
245 %]
246 Each source template can declare which section it's in via a META
248 directive:
249 [% META
251 title = 'General Information'
252 section = 'info'
253 %]
254 ...
255 This controls which section configuration file gets loaded to set
257 various other variables for defining the section title, menu, etc.
258 config/section/info:
260 [% section = {
262 name = section # save 'section' var as 'section.name'
263 title = 'Information'
264 menu = [ ... ]
265 # ...etc...
266 }
267 %]
268 This illustrates the basic principal but you can extend it to perform
270 pretty much any kind of per-document initialisation that you require.
271 Why do I get rubbish for my utf-8 templates?
273 First of all, make sure that your template files define a Byte Order
274 Mark <http://en.wikipedia.org/wiki/Byte_Order_Mark>
275 If you for some reason don't want to add BOM to your templates, you can
277 force Template to use a particular encoding (e.g. "utf8") for your
278 templates with the "ENCODING" option.
279 my $template = Template->new({
281 ENCODING => 'utf8'
282 });
283
285 Why is this FAQ so short?
286 Because we don't have anyone maintaining it.
287 Can I help?
289 Yes please :-)
290perl v5.12.0 2009-07-20 Template::FAQ(3)