1Template::Manual::FilteUrsse(r3)Contributed Perl DocumenTteamtpiloante::Manual::Filters(3)
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6 Template::Manual::Filters - Standard filters
7
9 The "format" filter takes a format string as a parameter (as per
10 "printf()") and formats each line of text accordingly.
11 [% FILTER format('<!-- %-40s -->') %]
13 This is a block of text filtered
14 through the above format.
15 [% END %]
16 Output:
18 <!-- This is a block of text filtered -->
20 <!-- through the above format. -->
21
23 Folds the input to UPPER CASE.
24 [% "hello world" FILTER upper %]
26 Output:
28 HELLO WORLD
30
32 Folds the input to lower case.
33 [% "Hello World" FILTER lower %]
35 Output:
37 hello world
39
41 Folds the first character of the input to UPPER CASE.
42 [% "hello" FILTER ucfirst %]
44 Output:
46 Hello
48
50 Folds the first character of the input to lower case.
51 [% "HELLO" FILTER lcfirst %]
53 Output:
55 hELLO
57
59 Trims any leading or trailing whitespace from the input text.
60 Particularly useful in conjunction with "INCLUDE", "PROCESS", etc.,
61 having the same effect as the "TRIM" configuration option.
62 [% INCLUDE myfile | trim %]
64
66 Collapse any whitespace sequences in the input text into a single
67 space. Leading and trailing whitespace (which would be reduced to a
68 single space) is removed, as per trim.
69 [% FILTER collapse %]
71 The cat
73 sat on
75 the mat
77 [% END %]
79 Output:
81 The cat sat on the mat
83
85 Converts the characters "<", ">", "&" and """ to "<", ">",
86 "&", and """ respectively, protecting them from being
87 interpreted as representing HTML tags or entities.
88 [% FILTER html %]
90 Binary "<=>" returns -1, 0, or 1 depending on...
91 [% END %]
92 Output:
94 Binary "<=>" returns -1, 0, or 1 depending on...
96
98 The "html" filter is fast and simple but it doesn't encode the full
99 range of HTML entities that your text may contain. The "html_entity"
100 filter uses either the "Apache::Util" module (which is written in C and
101 is therefore faster) or the "HTML::Entities" module (written in Perl
102 but equally as comprehensive) to perform the encoding.
103 If one or other of these modules are installed on your system then the
105 text will be encoded (via the "escape_html()" or "encode_entities()"
106 subroutines respectively) to convert all extended characters into their
107 appropriate HTML entities (e.g. converting '"e"' to '"é"'). If
108 neither module is available on your system then an '"html_entity"'
109 exception will be thrown reporting an appropriate message.
110 If you want to force TT to use one of the above modules in preference
112 to the other, then call either of the Template::Filters class methods:
113 use_html_entities() or use_apache_util().
114 use Template::Filters;
116 Template::Filters->use_html_entities;
117 For further information on HTML entity encoding, see
119 <http://www.w3.org/TR/REC-html40/sgml/entities.html>.
120
122 Same as the "html" filter, but adds "'" which is the fifth XML
123 built-in entity.
124
126 This filter formats a block of text into HTML paragraphs. A sequence
127 of two or more newlines is used as the delimiter for paragraphs which
128 are then wrapped in HTML "<p>"..."</p>" tags.
129 [% FILTER html_para %]
131 The cat sat on the mat.
132 Mary had a little lamb.
134 [% END %]
135 Output:
137 <p>
139 The cat sat on the mat.
140 </p>
141 <p>
143 Mary had a little lamb.
144 </p>
145
147 Similar to the html_para filter described above, but uses the HTML tag
148 sequence "<br><br>" to join paragraphs.
149 [% FILTER html_break %]
151 The cat sat on the mat.
152 Mary had a little lamb.
154 [% END %]
155 Output:
157 The cat sat on the mat.
159 <br>
160 <br>
161 Mary had a little lamb.
162
164 This filter replaces any newlines with "<br>" HTML tags, thus
165 preserving the line breaks of the original text in the HTML output.
166 [% FILTER html_line_break %]
168 The cat sat on the mat.
169 Mary had a little lamb.
170 [% END %]
171 Output:
173 The cat sat on the mat.<br>
175 Mary had a little lamb.<br>
176
178 This filter URI escapes the input text, converting any characters
179 outside of the permitted URI character set (as defined by RFC 2396)
180 into a %nn hex escape.
181 [% 'my file.html' | uri %]
183 Output:
185 my%20file.html
187 The uri filter correctly encodes all reserved characters, including
189 "&", "@", "/", ";", ":", "=", "+", "?" and "$". This filter is
190 typically used to encode parameters in a URL that could otherwise be
191 interpreted as part of the URL. Here's an example:
192 [% path = 'http://tt2.org/example'
194 back = '/other?foo=bar&baz=bam'
195 title = 'Earth: "Mostly Harmless"'
196 %]
197 <a href="[% path %]?back=[% back | uri %]&title=[% title | uri %]">
198 The output generated is rather long so we'll show it split across two
200 lines:
201 <a href="http://tt2.org/example?back=%2Fother%3Ffoo%3Dbar%26
203 baz%3Dbam&title=Earth%3A%20%22Mostly%20Harmless%22">
204 Without the uri filter the output would look like this (also split
206 across two lines).
207 <a href="http://tt2.org/example?back=/other?foo=bar
209 &baz=bam&title=Earth: "Mostly Harmless"">
210 In this rather contrived example we've manage to generate both a broken
212 URL (the repeated "?" is not allowed) and a broken HTML element (the
213 href attribute is terminated by the first """ after "Earth: " leaving
214 "Mostly Harmless"" dangling on the end of the tag in precisely the way
215 that harmless things shouldn't dangle). So don't do that. Always use
216 the uri filter to encode your URL parameters.
217 However, you should not use the uri filter to encode an entire URL.
219 <a href="[% page_url | uri %]"> # WRONG!
221 This will incorrectly encode any reserved characters like ":" and "/"
223 and that's almost certainly not what you want in this case. Instead
224 you should use the url (note spelling) filter for this purpose.
225 <a href="[% page_url | url %]"> # CORRECT
227 Please note that this behaviour was changed in version 2.16 of the
229 Template Toolkit. Prior to that, the uri filter did not encode the
230 reserved characters, making it technically incorrect according to the
231 RFC 2396 specification. So we fixed it in 2.16 and provided the url
232 filter to implement the old behaviour of not encoding reserved
233 characters.
234
236 The url filter is a less aggressive version of the uri filter. It
237 encodes any characters outside of the permitted URI character set (as
238 defined by RFC 2396) into %nn hex escapes. However, unlike the uri
239 filter, the url filter does not encode the reserved characters "&",
240 "@", "/", ";", ":", "=", "+", "?" and "$".
241
243 Indents the text block by a fixed pad string or width. The '"pad"'
244 argument can be specified as a string, or as a numerical value to
245 indicate a pad width (spaces). Defaults to 4 spaces if unspecified.
246 [% FILTER indent('ME> ') %]
248 blah blah blah
249 cabbages, rhubard, onions
250 [% END %]
251 Output:
253 ME> blah blah blah
255 ME> cabbages, rhubard, onions
256
258 Truncates the text block to the length specified, or a default length
259 of 32. Truncated text will be terminated with '"..."' (i.e. the
260 '"..."' falls inside the required length, rather than appending to
261 it).
262 [% FILTER truncate(21) %]
264 I have much to say on this matter that has previously
265 been said on more than one occasion.
266 [% END %]
267 Output:
269 I have much to say...
271 If you want to use something other than '"..."' you can pass that as a
273 second argument.
274 [% FILTER truncate(26, '…') %]
276 I have much to say on this matter that has previously
277 been said on more than one occasion.
278 [% END %]
279 Output:
281 I have much to say…
283
285 Repeats the text block for as many iterations as are specified
286 (default: 1).
287 [% FILTER repeat(3) %]
289 We want more beer and we want more beer,
290 [% END %]
291 We are the more beer wanters!
292 Output:
294 We want more beer and we want more beer,
296 We want more beer and we want more beer,
297 We want more beer and we want more beer,
298 We are the more beer wanters!
299
301 Searches the input text for any occurrences of the specified string and
302 removes them. A Perl regular expression may be specified as the search
303 string.
304 [% "The cat sat on the mat" FILTER remove('\s+') %]
306 Output:
308 Thecatsatonthemat
310
312 Similar to the remove filter described above, but taking a second
313 parameter which is used as a replacement string for instances of the
314 search string.
315 [% "The cat sat on the mat" | replace('\s+', '_') %]
317 Output:
319 The_cat_sat_on_the_mat
321
323 The "redirect" filter redirects the output of the block into a separate
324 file, specified relative to the "OUTPUT_PATH" configuration item.
325 [% FOREACH user IN myorg.userlist %]
327 [% FILTER redirect("users/${user.id}.html") %]
328 [% INCLUDE userinfo %]
329 [% END %]
330 [% END %]
331 or more succinctly, using side-effect notation:
333 [% FOREACH user IN myorg.userlist;
335 INCLUDE userinfo
336 FILTER redirect("users/${user.id}.html");
337 END
338 %]
339 A "file" exception will be thrown if the "OUTPUT_PATH" option is
341 undefined.
342 An optional "binmode" argument can follow the filename to explicitly
344 set the output file to binary mode.
345 [% PROCESS my/png/generator
347 FILTER redirect("images/logo.png", binmode=1) %]
348 For backwards compatibility with earlier versions, a single true/false
350 value can be used to set binary mode.
351 [% PROCESS my/png/generator
353 FILTER redirect("images/logo.png", 1) %]
354 For the sake of future compatibility and clarity, if nothing else, we
356 would strongly recommend you explicitly use the named "binmode" option
357 as shown in the first example.
358
360 The "eval" filter evaluates the block as template text, processing any
361 directives embedded within it. This allows template variables to
362 contain template fragments, or for some method to be provided for
363 returning template fragments from an external source such as a
364 database, which can then be processed in the template as required.
365 my $vars = {
367 fragment => "The cat sat on the [% place %]",
368 };
369 $template->process($file, $vars);
370 The following example:
372 [% fragment | eval %]
374 is therefore equivalent to
376 The cat sat on the [% place %]
378 The "evaltt" filter is provided as an alias for "eval".
380
382 The "perl" filter evaluates the block as Perl code. The "EVAL_PERL"
383 option must be set to a true value or a "perl" exception will be
384 thrown.
385 [% my_perl_code | perl %]
387 In most cases, the "[% PERL %]" ... "[% END %]" block should suffice
389 for evaluating Perl code, given that template directives are processed
390 before being evaluate as Perl. Thus, the previous example could have
391 been written in the more verbose form:
392 [% PERL %]
394 [% my_perl_code %]
395 [% END %]
396 as well as
398 [% FILTER perl %]
400 [% my_perl_code %]
401 [% END %]
402 The "evalperl" filter is provided as an alias for "perl" for backwards
404 compatibility.
405
407 The stdout filter prints the output generated by the enclosing block to
408 "STDOUT". The "binmode" option can be passed as either a named
409 parameter or a single argument to set "STDOUT" to binary mode (see the
410 binmode perl function).
411 [% PROCESS something/cool
413 FILTER stdout(binmode=1) # recommended %]
414 [% PROCESS something/cool
416 FILTER stdout(1) # alternate %]
417 The "stdout" filter can be used to force "binmode" on "STDOUT", or also
419 inside "redirect", "null" or "stderr" blocks to make sure that
420 particular output goes to "STDOUT". See the "null" filter below for an
421 example.
422
424 The stderr filter prints the output generated by the enclosing block to
425 "STDERR".
426
428 The "null" filter prints nothing. This is useful for plugins whose
429 methods return values that you don't want to appear in the output.
430 Rather than assigning every plugin method call to a dummy variable to
431 silence it, you can wrap the block in a null filter:
432 [% FILTER null;
434 USE im = GD.Image(100,100);
435 black = im.colorAllocate(0, 0, 0);
436 red = im.colorAllocate(255,0, 0);
437 blue = im.colorAllocate(0, 0, 255);
438 im.arc(50,50,95,75,0,360,blue);
439 im.fill(50,50,red);
440 im.png | stdout(1);
441 END;
442 -%]
443 Notice the use of the "stdout" filter to ensure that a particular
445 expression generates output to "STDOUT" (in this case in binary mode).
446
448 Hey! The above document had some coding errors, which are explained
449 below:
450 Around line 128:
452 Non-ASCII character seen before =encoding in ''C<e>''. Assuming
453 ISO8859-1
454perl v5.16.3 2011-12-20 Template::Manual::Filters(3)