Template::Manual::FiltUser3Contributed Perl DocumeTemplate::Manual::Filters(3)NAMETemplate::Manual::Filters - Standard filters
format(format)
The "format" filter takes a format string as a parameter (as per
"printf()") and formats each line of text accordingly.
[% FILTER format('<!-- %-40s -->') %]
This is a block of text filtered
through the above format.
[% END %]
Output:
<!-- This is a block of text filtered -->
<!-- through the above format. -->
upper
Folds the input to UPPER CASE.
[% "hello world" FILTER upper %]
Output:
HELLO WORLD
lower
Folds the input to lower case.
[% "Hello World" FILTER lower %]
Output:
hello world
ucfirst
Folds the first character of the input to UPPER CASE.
[% "hello" FILTER ucfirst %]
Output:
Hello
lcfirst
Folds the first character of the input to lower case.
[% "HELLO" FILTER lcfirst %]
Output:
hELLO
trim
Trims any leading or trailing whitespace from the input text.
Particularly useful in conjunction with "INCLUDE", "PROCESS", etc.,
having the same effect as the "TRIM" configuration option.
[% INCLUDE myfile | trim %]
collapse
Collapse any whitespace sequences in the input text into a single
space. Leading and trailing whitespace (which would be reduced to a
single space) is removed, as per trim.
[% FILTER collapse %]
The cat
sat on
the mat
[% END %]
Output:
The cat sat on the mat
html
Converts the characters "<", ">", "&" and """ to "<", ">",
"&", and """ respectively, protecting them from being
interpreted as representing HTML tags or entities.
[% FILTER html %]
Binary "<=>" returns -1, 0, or 1 depending on...
[% END %]
Output:
Binary "<=>" returns -1, 0, or 1 depending on...
html_entity
The "html" filter is fast and simple but it doesn't encode the full
range of HTML entities that your text may contain. The "html_entity"
filter uses either the "Apache::Util" module (which is written in C and
is therefore faster) or the "HTML::Entities" module (written in Perl
but equally as comprehensive) to perform the encoding.
If one or other of these modules are installed on your system then the
text will be encoded (via the "escape_html()" or "encode_entities()"
subroutines respectively) to convert all extended characters into their
appropriate HTML entities (e.g. converting '"e"' to '"é"'). If
neither module is available on your system then an '"html_entity"'
exception will be thrown reporting an appropriate message.
If you want to force TT to use one of the above modules in preference
to the other, then call either of the Template::Filters class methods:
use_html_entities() or use_apache_util().
use Template::Filters;
Template::Filters->use_html_entities;
For further information on HTML entity encoding, see
http://www.w3.org/TR/REC-html40/sgml/entities.html
<http://www.w3.org/TR/REC-html40/sgml/entities.html>.
xml
Same as the "html" filter, but adds "'" which is the fifth XML
built-in entity.
html_para
This filter formats a block of text into HTML paragraphs. A sequence
of two or more newlines is used as the delimiter for paragraphs which
are then wrapped in HTML "<p>"..."</p>" tags.
[% FILTER html_para %]
The cat sat on the mat.
Mary had a little lamb.
[% END %]
Output:
<p>
The cat sat on the mat.
</p>
<p>
Mary had a little lamb.
</p>
html_break / html_para_break
Similar to the html_para filter described above, but uses the HTML tag
sequence "<br><br>" to join paragraphs.
[% FILTER html_break %]
The cat sat on the mat.
Mary had a little lamb.
[% END %]
Output:
The cat sat on the mat.
<br>
<br>
Mary had a little lamb.
html_line_break
This filter replaces any newlines with "<br>" HTML tags, thus
preserving the line breaks of the original text in the HTML output.
[% FILTER html_line_break %]
The cat sat on the mat.
Mary had a little lamb.
[% END %]
Output:
The cat sat on the mat.<br>
Mary had a little lamb.<br>
uri
This filter URI escapes the input text, converting any characters
outside of the permitted URI character set (as defined by RFC 2396)
into a %nn hex escape.
[% 'my file.html' | uri %]
Output:
my%20file.html
The uri filter correctly encodes all reserved characters, including
"&", "@", "/", ";", ":", "=", "+", "?" and "$". This filter is
typically used to encode parameters in a URL that could otherwise be
interpreted as part of the URL. Here's an example:
[% path = 'http://tt2.org/example'
back = '/other?foo=bar&baz=bam'
title = 'Earth: "Mostly Harmless"'
%]
<a href="[% path %]?back=[% back | uri %]&title=[% title | uri %]">
The output generated is rather long so we'll show it split across two
lines:
<a href="http://tt2.org/example?back=%2Fother%3Ffoo%3Dbar%26
baz%3Dbam&title=Earth%3A%20%22Mostly%20Harmless%22">
Without the uri filter the output would look like this (also split
across two lines).
<a href="http://tt2.org/example?back=/other?foo=bar
&baz=bam&title=Earth: "Mostly Harmless"">
In this rather contrived example we've manage to generate both a broken
URL (the repeated "?" is not allowed) and a broken HTML element (the
href attribute is terminated by the first """ after "Earth: " leaving
"Mostly Harmless"" dangling on the end of the tag in precisely the way
that harmless things shouldn't dangle). So don't do that. Always use
the uri filter to encode your URL parameters.
However, you should not use the uri filter to encode an entire URL.
<a href="[% page_url | uri %]"> # WRONG!
This will incorrectly encode any reserved characters like ":" and "/"
and that's almost certainly not what you want in this case. Instead
you should use the url (note spelling) filter for this purpose.
<a href="[% page_url | url %]"> # CORRECT
Please note that this behaviour was changed in version 2.16 of the
Template Toolkit. Prior to that, the uri filter did not encode the
reserved characters, making it technically incorrect according to the
RFC 2396 specification. So we fixed it in 2.16 and provided the url
filter to implement the old behaviour of not encoding reserved
characters.
url
The url filter is a less aggressive version of the uri filter. It
encodes any characters outside of the permitted URI character set (as
defined by RFC 2396) into %nn hex escapes. However, unlike the uri
filter, the url filter does not encode the reserved characters "&",
"@", "/", ";", ":", "=", "+", "?" and "$".
indent(pad)
Indents the text block by a fixed pad string or width. The '"pad"'
argument can be specified as a string, or as a numerical value to
indicate a pad width (spaces). Defaults to 4 spaces if unspecified.
[% FILTER indent('ME> ') %]
blah blah blah
cabbages, rhubard, onions
[% END %]
Output:
ME> blah blah blah
ME> cabbages, rhubard, onions
truncate(length,dots)
Truncates the text block to the length specified, or a default length
of 32. Truncated text will be terminated with '"..."' (i.e. the
'"..."' falls inside the required length, rather than appending to
it).
[% FILTER truncate(21) %]
I have much to say on this matter that has previously
been said on more than one occasion.
[% END %]
Output:
I have much to say...
If you want to use something other than '"..."' you can pass that as a
second argument.
[% FILTER truncate(26, '…') %]
I have much to say on this matter that has previously
been said on more than one occasion.
[% END %]
Output:
I have much to say…
repeat(iterations)
Repeats the text block for as many iterations as are specified
(default: 1).
[% FILTER repeat(3) %]
We want more beer and we want more beer,
[% END %]
We are the more beer wanters!
Output:
We want more beer and we want more beer,
We want more beer and we want more beer,
We want more beer and we want more beer,
We are the more beer wanters!
remove(string)
Searches the input text for any occurrences of the specified string and
removes them. A Perl regular expression may be specified as the search
string.
[% "The cat sat on the mat" FILTER remove('\s+') %]
Output:
Thecatsatonthemat
replace(search, replace)
Similar to the remove filter described above, but taking a second
parameter which is used as a replacement string for instances of the
search string.
[% "The cat sat on the mat" | replace('\s+', '_') %]
Output:
The_cat_sat_on_the_mat
redirect(file, options)
The "redirect" filter redirects the output of the block into a separate
file, specified relative to the "OUTPUT_PATH" configuration item.
[% FOREACH user IN myorg.userlist %]
[% FILTER redirect("users/${user.id}.html") %]
[% INCLUDE userinfo %]
[% END %]
[% END %]
or more succinctly, using side-effect notation:
[% FOREACH user IN myorg.userlist;
INCLUDE userinfo
FILTER redirect("users/${user.id}.html");
END
%]
A "file" exception will be thrown if the "OUTPUT_PATH" option is
undefined.
An optional "binmode" argument can follow the filename to explicitly
set the output file to binary mode.
[% PROCESS my/png/generator
FILTER redirect("images/logo.png", binmode=1) %]
For backwards compatibility with earlier versions, a single true/false
value can be used to set binary mode.
[% PROCESS my/png/generator
FILTER redirect("images/logo.png", 1) %]
For the sake of future compatibility and clarity, if nothing else, we
would strongly recommend you explicitly use the named "binmode" option
as shown in the first example.
eval / evaltt
The "eval" filter evaluates the block as template text, processing any
directives embedded within it. This allows template variables to
contain template fragments, or for some method to be provided for
returning template fragments from an external source such as a
database, which can then be processed in the template as required.
my $vars = {
fragment => "The cat sat on the [% place %]",
};
$template->process($file, $vars);
The following example:
[% fragment | eval %]
is therefore equivalent to
The cat sat on the [% place %]
The "evaltt" filter is provided as an alias for "eval".
perl / evalperl
The "perl" filter evaluates the block as Perl code. The "EVAL_PERL"
option must be set to a true value or a "perl" exception will be
thrown.
[% my_perl_code | perl %]
In most cases, the "[% PERL %]" ... "[% END %]" block should suffice
for evaluating Perl code, given that template directives are processed
before being evaluate as Perl. Thus, the previous example could have
been written in the more verbose form:
[% PERL %]
[% my_perl_code %]
[% END %]
as well as
[% FILTER perl %]
[% my_perl_code %]
[% END %]
The "evalperl" filter is provided as an alias for "perl" for backwards
compatibility.
stdout(options)
The stdout filter prints the output generated by the enclosing block to
"STDOUT". The "binmode" option can be passed as either a named
parameter or a single argument to set "STDOUT" to binary mode (see the
binmode perl function).
[% PROCESS something/cool
FILTER stdout(binmode=1) # recommended %]
[% PROCESS something/cool
FILTER stdout(1) # alternate %]
The "stdout" filter can be used to force "binmode" on "STDOUT", or also
inside "redirect", "null" or "stderr" blocks to make sure that
particular output goes to "STDOUT". See the "null" filter below for an
example.
stderr
The stderr filter prints the output generated by the enclosing block to
"STDERR".
null
The "null" filter prints nothing. This is useful for plugins whose
methods return values that you don't want to appear in the output.
Rather than assigning every plugin method call to a dummy variable to
silence it, you can wrap the block in a null filter:
[% FILTER null;
USE im = GD.Image(100,100);
black = im.colorAllocate(0, 0, 0);
red = im.colorAllocate(255,0, 0);
blue = im.colorAllocate(0, 0, 255);
im.arc(50,50,95,75,0,360,blue);
im.fill(50,50,red);
im.png | stdout(1);
END;
-%]
Notice the use of the "stdout" filter to ensure that a particular
expression generates output to "STDOUT" (in this case in binary mode).
perl v5.14.3 2011-12-20 Template::Manual::Filters(3)
