# Template::Manual::Filters - phpMan

## NAME
    [Template::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 "&lt;", "&gt;",
    "&amp;", and "&quot;" 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 "&lt;=&gt;" 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 '"?"' to '"&eacute;"'). 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>>.

xml
    Same as the "html" filter, but adds "&apos;" 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 3986) 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 (since superceded by RFC2732 and RFC3986). So we
    fixed it in 2.16 and provided the url filter to implement the old
    behaviour of not encoding reserved characters.

    As of version 2.26 of the Template Toolkit, the "uri" and url filters
    use the unsafe character set defined by RFC3986. This means that certain
    characters ("(", ")", "~", "*", "!" and the single quote "'") are now
    deemed unsafe and will be escaped as hex character sequences. The double
    quote character ('"') is now deemed safe and will not be escaped.

    If you want to enable the old behaviour then call the "use_rfc2732()"
    method in [Template::Filters]

        use [Template::Filters]
        [Template::Filters]->use_rfc2732;

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, '&hellip;') %]
        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&hellip;

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).

