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
142 How can I find out the name of the main template being processed?
143 The "template" variable contains a reference to the Template::Document
144 object for the main template you're processing (i.e. the one provided
145 as the first argument to the Template process() method). The "name"
146 method returns its name.
147 [% template.name %] # e.g. index.html
149 How can I find out the name of the current template being processed?
151 The "template" variable always references the main template being
152 processed. So even if you call [% INCLUDE header %], and that calls [%
153 INCLUDE menu %], the "template" variable will be unchanged.
154 index.html:
156 [% template.name %] # index.html
158 [% INCLUDE header %]
159 header:
161 [% template.name %] # index.html
163 [% INCLUDE menu %]
164 menu:
166 [% template.name %] # index.html
168 In contrast, the "component" variable always references the current
170 template being processed.
171 index.html
173 [% component.name %] # index.html
175 [% INCLUDE header %]
176 header:
178 [% component.name %] # header
180 [% INCLUDE menu %]
181 menu:
183 [% component.name %] # menu
185 How do I print the modification time of the template or component?
187 The "template" and "component" variables reference the main template
188 and the current template being processed (see previous questions). The
189 "modtime" method returns the modification time of the corresponding
190 template file as a number of seconds since the Unix epoch (00:00:00 GMT
191 1st January 1970).
192 This number doesn't mean much to anyone (except perhaps serious Unix
194 geeks) so you'll probably want to use the Date plugin to format it for
195 human consumption.
196 [% USE Date %]
198 [% template.name %] last modified [% Date.format(template.modtime) %]
199 How can I configure variables on a per-request basis?
201 One easy way to achieve this is to define a single "PRE_PROCESS"
202 template which loads in other configuration files based on variables
203 defined or other conditions.
204 For example, my setup usually looks something like this:
206 PRE_PROCESS => 'config/main'
208 config/main:
210 [% DEFAULT style = 'text'
212 section = template.section or 'home';
213 PROCESS config/site
215 + config/urls
216 + config/macros
217 + "config/style/$style"
218 + "config/section/$section"
219 + ...
220 %]
221 This allows me to set a single 'style' variable to control which config
223 file gets pre-processed to set my various style options (colours, img
224 paths, etc). For example:
225 config/style/basic:
227 [% style = {
229 name = style # save existing 'style' var as 'style.name'
230 # define various other style variables....
232 col = {
233 back => '#ffffff'
234 text => '#000000'
235 # ...etc...
236 }
237 logo = {
239 # ...etc...
240 }
241 # ...etc...
243 }
244 %]
245 Each source template can declare which section it's in via a META
247 directive:
248 [% META
250 title = 'General Information'
251 section = 'info'
252 %]
253 ...
254 This controls which section configuration file gets loaded to set
256 various other variables for defining the section title, menu, etc.
257 config/section/info:
259 [% section = {
261 name = section # save 'section' var as 'section.name'
262 title = 'Information'
263 menu = [ ... ]
264 # ...etc...
265 }
266 %]
267 This illustrates the basic principal but you can extend it to perform
269 pretty much any kind of per-document initialisation that you require.
270 Why do I get rubbish for my utf-8 templates?
272 First of all, make sure that your template files define a Byte Order
273 Mark <http://en.wikipedia.org/wiki/Byte_Order_Mark>
274 If you for some reason don't want to add BOM to your templates, you can
276 force Template to use a particular encoding (e.g. "utf8") for your
277 templates with the "ENCODING" option.
278 my $template = Template->new({
280 ENCODING => 'utf8'
281 });
282
284 Why is this FAQ so short?
285 Because we don't have anyone maintaining it.
286 Can I help?
288 Yes please :-)
289perl v5.30.0 2019-07-26 Template::FAQ(3)