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 '"?"' 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 3986)
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 (since superceded by RFC2732 and RFC3986). So
232 we fixed it in 2.16 and provided the url filter to implement the old
233 behaviour of not encoding reserved characters.
234 As of version 2.28 of the Template Toolkit, the "uri" and url filters
236 use the unsafe character set defined by RFC3986. This means that
237 certain characters ("(", ")", "*", "!", "'", and '"') are now deemed
238 unsafe and will be escaped as hex character sequences.
239 The ability to use the RFC3986 character set was added in 2.26 but not
241 enabled by default; double quote was incorrectly deemed safe in 2.26
242 but correctly escaped in 2.27.
243 If you want to enable the old behaviour then call the "use_rfc2732()"
245 method in Template::Filters
246 use Template::Filters
248 Template::Filters->use_rfc2732;
249
251 The url filter is a less aggressive version of the uri filter. It
252 encodes any characters outside of the permitted URI character set (as
253 defined by RFC 2396) into %nn hex escapes. However, unlike the uri
254 filter, the url filter does not encode the reserved characters "&",
255 "@", "/", ";", ":", "=", "+", "?" and "$".
256
258 Indents the text block by a fixed pad string or width. The '"pad"'
259 argument can be specified as a string, or as a numerical value to
260 indicate a pad width (spaces). Defaults to 4 spaces if unspecified.
261 [% FILTER indent('ME> ') %]
263 blah blah blah
264 cabbages, rhubard, onions
265 [% END %]
266 Output:
268 ME> blah blah blah
270 ME> cabbages, rhubard, onions
271
273 Truncates the text block to the length specified, or a default length
274 of 32. Truncated text will be terminated with '"..."' (i.e. the
275 '"..."' falls inside the required length, rather than appending to
276 it).
277 [% FILTER truncate(21) %]
279 I have much to say on this matter that has previously
280 been said on more than one occasion.
281 [% END %]
282 Output:
284 I have much to say...
286 If you want to use something other than '"..."' you can pass that as a
288 second argument.
289 [% FILTER truncate(26, '…') %]
291 I have much to say on this matter that has previously
292 been said on more than one occasion.
293 [% END %]
294 Output:
296 I have much to say…
298
300 Repeats the text block for as many iterations as are specified
301 (default: 1).
302 [% FILTER repeat(3) %]
304 We want more beer and we want more beer,
305 [% END %]
306 We are the more beer wanters!
307 Output:
309 We want more beer and we want more beer,
311 We want more beer and we want more beer,
312 We want more beer and we want more beer,
313 We are the more beer wanters!
314
316 Searches the input text for any occurrences of the specified string and
317 removes them. A Perl regular expression may be specified as the search
318 string.
319 [% "The cat sat on the mat" FILTER remove('\s+') %]
321 Output:
323 Thecatsatonthemat
325
327 Similar to the remove filter described above, but taking a second
328 parameter which is used as a replacement string for instances of the
329 search string.
330 [% "The cat sat on the mat" | replace('\s+', '_') %]
332 Output:
334 The_cat_sat_on_the_mat
336
338 The "redirect" filter redirects the output of the block into a separate
339 file, specified relative to the "OUTPUT_PATH" configuration item.
340 [% FOREACH user IN myorg.userlist %]
342 [% FILTER redirect("users/${user.id}.html") %]
343 [% INCLUDE userinfo %]
344 [% END %]
345 [% END %]
346 or more succinctly, using side-effect notation:
348 [% FOREACH user IN myorg.userlist;
350 INCLUDE userinfo
351 FILTER redirect("users/${user.id}.html");
352 END
353 %]
354 A "file" exception will be thrown if the "OUTPUT_PATH" option is
356 undefined.
357 An optional "binmode" argument can follow the filename to explicitly
359 set the output file to binary mode.
360 [% PROCESS my/png/generator
362 FILTER redirect("images/logo.png", binmode=1) %]
363 For backwards compatibility with earlier versions, a single true/false
365 value can be used to set binary mode.
366 [% PROCESS my/png/generator
368 FILTER redirect("images/logo.png", 1) %]
369 For the sake of future compatibility and clarity, if nothing else, we
371 would strongly recommend you explicitly use the named "binmode" option
372 as shown in the first example.
373
375 The "eval" filter evaluates the block as template text, processing any
376 directives embedded within it. This allows template variables to
377 contain template fragments, or for some method to be provided for
378 returning template fragments from an external source such as a
379 database, which can then be processed in the template as required.
380 my $vars = {
382 fragment => "The cat sat on the [% place %]",
383 };
384 $template->process($file, $vars);
385 The following example:
387 [% fragment | eval %]
389 is therefore equivalent to
391 The cat sat on the [% place %]
393 The "evaltt" filter is provided as an alias for "eval".
395
397 The "perl" filter evaluates the block as Perl code. The "EVAL_PERL"
398 option must be set to a true value or a "perl" exception will be
399 thrown.
400 [% my_perl_code | perl %]
402 In most cases, the "[% PERL %]" ... "[% END %]" block should suffice
404 for evaluating Perl code, given that template directives are processed
405 before being evaluate as Perl. Thus, the previous example could have
406 been written in the more verbose form:
407 [% PERL %]
409 [% my_perl_code %]
410 [% END %]
411 as well as
413 [% FILTER perl %]
415 [% my_perl_code %]
416 [% END %]
417 The "evalperl" filter is provided as an alias for "perl" for backwards
419 compatibility.
420
422 The stdout filter prints the output generated by the enclosing block to
423 "STDOUT". The "binmode" option can be passed as either a named
424 parameter or a single argument to set "STDOUT" to binary mode (see the
425 binmode perl function).
426 [% PROCESS something/cool
428 FILTER stdout(binmode=1) # recommended %]
429 [% PROCESS something/cool
431 FILTER stdout(1) # alternate %]
432 The "stdout" filter can be used to force "binmode" on "STDOUT", or also
434 inside "redirect", "null" or "stderr" blocks to make sure that
435 particular output goes to "STDOUT". See the "null" filter below for an
436 example.
437
439 The stderr filter prints the output generated by the enclosing block to
440 "STDERR".
441
443 The "null" filter prints nothing. This is useful for plugins whose
444 methods return values that you don't want to appear in the output.
445 Rather than assigning every plugin method call to a dummy variable to
446 silence it, you can wrap the block in a null filter:
447 [% FILTER null;
449 USE im = GD.Image(100,100);
450 black = im.colorAllocate(0, 0, 0);
451 red = im.colorAllocate(255,0, 0);
452 blue = im.colorAllocate(0, 0, 255);
453 im.arc(50,50,95,75,0,360,blue);
454 im.fill(50,50,red);
455 im.png | stdout(1);
456 END;
457 -%]
458 Notice the use of the "stdout" filter to ensure that a particular
460 expression generates output to "STDOUT" (in this case in binary mode).
461perl v5.34.0 2022-01-21 Template::Manual::Filters(3)