| HTML::Template::PerlInterface(3pm) | User Contributed Perl Documentation | HTML::Template::PerlInterface(3pm) |
HTML::Template::PerlInterface - perl interface of HTML::Template::Pro
This help is only on perl interface of HTML::Template::Pro. For syntax of html template files you should see "SYNOPSIS" in HTML::Template::SYNTAX.
First you make a template - this is just a normal HTML file with a few extra tags, the simplest being <TMPL_VAR>
For example, test.tmpl:
<html> <head><title>Test Template</title> <body> My Home Directory is <TMPL_VAR NAME=HOME> <p> My Path is set to <TMPL_VAR NAME=PATH> </body> </html>
See HTML::Template::SYNTAX for their syntax.
Now create a small CGI program:
#!/usr/bin/perl -w
use HTML::Template::Pro;
# open the html template
my $template = HTML::Template::Pro->new(
filename => 'test.tmpl',
case_sensitive=> 1);
# fill in some parameters
$template->param(HOME => $ENV{HOME});
$template->param(PATH => $ENV{PATH});
# send the obligatory Content-Type and print the template output
print "Content-Type: text/html\n\n";
# print output
$template->output(print_to=>\*STDOUT);
# this would also work.
# print $template->output();
# this would also work. It is faster,
# but (WARNING!) not compatible with original HTML::Template.
# $template->output();
If all is well in the universe this should show something like this in your browser when visiting the CGI:
My Home Directory is /home/some/directory My Path is set to /bin;/usr/bin
For the best performance it is recommended to use case_sensitive=>1 in new() and print_to=>\*STDOUT in output().
Note that (HTML::Template::Pro version 0.90+) output(), called in void context, also prints to stdout using built-in htmltmplpro C library calls, so the last call "$template->output();" might be, in fact, the fastest way to call output().
IMPORTANT NOTE: you can safely write
my $template = HTML::Template->new( ... options ...)
or even
my $template = HTML::Template::Expr->new( ... options ...)
with HTML::Template::Pro, because in absence of original HTML::Template and HTML::Template::Expr HTML::Template::Pro intercepts their calls.
You can also use all three modules and safely mix their calls (benchmarking may be the only reason for it). In case you want to mix calls to HTML::Template::Expr and HTML::Template::Pro, the only proper usage of their load is
use HTML::Template; use HTML::Template::Expr; use HTML::Template::Pro;
Of course, if you don't plan to mix them (in most cases) it is enough to simply write
use HTML::Template::Pro;
Simply use HTML::Template::Pro, it supports all functions of HTML::Template::Expr.
HTML::Template::Pro is a fast C/perl+XS implementation of HTML::Template and HTML::Template::Expr. See HTML::Template::Pro for details.
It fully supports template language of HTML::Template as described in HTML::Template::SYNTAX.
Briefly,
"This module attempts to make using HTML templates simple and natural. It extends standard HTML with a few new HTML-esque tags - <TMPL_VAR>, <TMPL_LOOP>, <TMPL_INCLUDE>, <TMPL_IF>, <TMPL_ELSE> and <TMPL_UNLESS>. The file written with HTML and these new tags is called a template. It is usually saved separate from your script - possibly even created by someone else! Using this module you fill in the values for the variables, loops and branches declared in the template. This allows you to separate design - the HTML - from the data, which you generate in the Perl script."
Here is described a perl interface of HTML::Template::Pro and HTML::Template + HTML::Template::Expr. See DISTINCTIONS for brief summary of distinctions between HTML::Template::Pro and HTML::Template.
Call new() to create a new Template object:
my $template = HTML::Template->new( filename => 'file.tmpl',
option => 'value'
);
You must call new() with at least one name => value pair specifying how to access the template text. You can use "filename => 'file.tmpl'" to specify a filename to be opened as the template. Alternately you can use:
my $t = HTML::Template->new( scalarref => $ref_to_template_text,
option => 'value'
);
and
my $t = HTML::Template->new( arrayref => $ref_to_array_of_lines ,
option => 'value'
);
These initialize the template from in-memory resources. In almost every case you'll want to use the filename parameter. If you're worried about all the disk access from reading a template file just use mod_perl and the cache option detailed below.
You can also read the template from an already opened filehandle, either traditionally as a glob or as a FileHandle:
my $t = HTML::Template->new( filehandle => *FH, option => 'value');
The four new() calling methods can also be accessed as below, if you prefer.
my $t = HTML::Template->new_file('file.tmpl', option => 'value');
my $t = HTML::Template->new_scalar_ref($ref_to_template_text,
option => 'value');
my $t = HTML::Template->new_array_ref($ref_to_array_of_lines,
option => 'value');
my $t = HTML::Template->new_filehandle($fh,
option => 'value');
And as a final option, for those that might prefer it, you can call new as:
my $t = HTML::Template->new(type => 'filename',
source => 'file.tmpl');
Which works for all three of the source types.
If the environment variable HTML_TEMPLATE_ROOT is set and your filename doesn't begin with /, then the path will be relative to the value of $HTML_TEMPLATE_ROOT. Example - if the environment variable HTML_TEMPLATE_ROOT is set to "/home/sam" and I call HTML::Template->new() with filename set to "sam.tmpl", the HTML::Template will try to open "/home/sam/sam.tmpl" to access the template file. You can also affect the search path for files with the "path" option to new() - see below for more information.
You can modify the Template object's behavior with new(). The options are available:
HTML::Template::Pro always use die_on_bad_params => 0. It currently can't be changed, because HTML::Template::Pro can't know whether a parameter is bad until it finishes output.
Note that it is wrapper-only option: it is not implemented in the htmltmplpro C library.
In the original HTML::Template, if the "force_untaint" option is set an error occurs if you try to set a value that is tainted in the param() call. In HTML::Template::Pro, an error occurs when output is called.
Note that the tainted value will never be printed; but, to completely suppress output, one should use call to output() that returns string, like print $tmpl->output(); Then output() will die before it returns the string to print.
Note that it is wrapper-only perl-specific option: it is not implemented in the htmltmplpro C library.
<TMPL_HUH NAME=ZUH>
Would normally cause an error, but if you call new with strict => 0, HTML::Template will ignore it. Defaults to 1.
HTML::Template::Pro always implies strict => 0.
Since HTML::Template::Pro parses and outputs templates at once, it silently ignores those options.
Example:
my $template = HTML::Template->new( filename => 'file.tmpl',
path => [ '/path/to/templates',
'/alternate/path'
]
);
NOTE: the paths in the path list must be expressed as UNIX paths, separated by the forward-slash character ('/').
my $query = new CGI;
my $template = HTML::Template->new(filename => 'template.tmpl',
associate => $query);
Now, "$template->output()" will act as though
$template->param('FormField', $cgi->param('FormField'));
had been specified for each key/value pair that would be provided by the "$cgi->param()" method. Parameters you set directly take precedence over associated parameters.
You can specify multiple objects to associate by passing an anonymous array to the associate option. They are searched for parameters in the order they appear:
my $template = HTML::Template->new(filename => 'template.tmpl',
associate => [$query, $other_obj]);
NOTE: If the option case_sensitive => 0, the parameter names are matched in a case-insensitive manner. If you have two parameters in a CGI object like 'NAME' and 'Name' one will be chosen randomly by associate. This behavior can be changed by setting option case_sensitive to 1.
my $template = HTML::Template->new(filename => 'template.tmpl',
case_sensitive => 1);
$template->param(
FieldA => 'foo',
fIELDa => 'bar',
);
This option defaults to off to keep compatibility with HTML::Template. Nevertheless, setting case_sensitive => 1 is encouraged, because it significantly improves performance.
If case_sensitive is set to 0, the perl wrapper is forced to lowercase keys in every hash it will find in "param" tree, which is sometimes an expensive operation. To avoid this, set case_sensitive => 1.
If case conversion is necessary, there is an alternative lightweight option tmpl_var_case, which is HTML::Template::Pro specific.
Note that case_sensitive is wrapper-only option: it is not implemented in the htmltmplpro C library.
For example, in case of <tmpl_var name="CamelCaseName"> setting tmpl_var_case = ASK_NAME_AS_IS | ASK_NAME_LOWERCASE | ASK_NAME_UPPERCASE will cause HTML::Template::Pro to look into "param" tree for 3 names: CamelCaseName, camelcasename, and CAMELCASENAME.
By default, the name is asked "as is".
In addition to the above, a __counter__ var is also made available when loop context variables are turned on.
Example:
<TMPL_LOOP NAME="FOO">
<TMPL_IF NAME="__first__">
This only outputs on the first pass.
</TMPL_IF>
<TMPL_IF NAME="__odd__">
This outputs every other pass, on the odd passes.
</TMPL_IF>
<TMPL_UNLESS NAME="__odd__">
This outputs every other pass, on the even passes.
</TMPL_UNLESS>
<TMPL_IF NAME="__inner__">
This outputs on passes that are neither first nor last.
</TMPL_IF>
This is pass number <TMPL_VAR NAME="__counter__">.
<TMPL_IF NAME="__last__">
This only outputs on the last pass.
</TMPL_IF>
</TMPL_LOOP>
One use of this feature is to provide a "separator" similar in effect to the perl function join(). Example:
<TMPL_LOOP FRUIT>
<TMPL_IF __last__> and </TMPL_IF>
<TMPL_VAR KIND><TMPL_UNLESS __last__>, <TMPL_ELSE>.</TMPL_UNLESS>
</TMPL_LOOP>
Would output (in a browser) something like:
Apples, Oranges, Brains, Toes, and Kiwi.
Given an appropriate "param()" call, of course. NOTE: A loop with only a single pass will get both __first__ and __last__ set to true, but not __inner__.
NOTE: in the original HTML::Template with case_sensitive = 1 and loop_context_vars the special loop variables are available in lower-case only. In HTML::Template::Pro they are recognized regardless of case.
Example:
This is a normal variable: <TMPL_VAR NORMAL>.<P>
<TMPL_LOOP NAME=FROOT_LOOP>
Here it is inside the loop: <TMPL_VAR NORMAL><P>
</TMPL_LOOP>
Normally this wouldn't work as expected, since <TMPL_VAR NORMAL>'s value outside the loop is not available inside the loop.
The global_vars option also allows you to access the values of an enclosing loop within an inner loop. For example, in this loop the inner loop will have access to the value of OUTER_VAR in the correct iteration:
<TMPL_LOOP OUTER_LOOP>
OUTER: <TMPL_VAR OUTER_VAR>
<TMPL_LOOP INNER_LOOP>
INNER: <TMPL_VAR INNER_VAR>
INSIDE OUT: <TMPL_VAR OUTER_VAR>
</TMPL_LOOP>
</TMPL_LOOP>
NOTE: "global_vars" is not "global_loops" (which does not exist). That means that loops you declare at one scope are not available inside other loops even when "global_vars" is on.
Example: {{{ <TMPL_LOOP NAME=class>
<TMPL_LOOP NAME=person>
<TMPL_VAR NAME="../teacher_name"> <!-- access to
class.teacher_name -->
<TMPL_VAR NAME="name">
<TMPL_VAR NAME="/top_level_value"> <!-- access to top
level value -->
<TMPL_VAR NAME="age">
<TMPL_LOOP NAME="../../school"> <!-- enter loop before
accessing its vars -->
<TMPL_VAR NAME="school_name"> <!-- access to
[../../]school.school_name -->
</TMPL_LOOP>
</TMPL_LOOP> </TMPL_LOOP> }}}
In the most simple usage, you simply assign a code reference to the filter parameter. This subroutine will receive a single argument - a reference to a string containing the template file text. Here is an example that accepts templates with tags that look like "!!!ZAP_VAR FOO!!!" and transforms them into HTML::Template tags:
my $filter = sub {
my $text_ref = shift;
$$text_ref =~ s/!!!ZAP_(.*?)!!!/<TMPL_$1>/g;
};
# open zap.tmpl using the above filter
my $template = HTML::Template->new(filename => 'zap.tmpl',
filter => $filter);
More complicated usages are possible. You can request that your filter receive the template text as an array of lines rather than as a single scalar. To do that you need to specify your filter using a hash-ref. In this form you specify the filter using the "sub" key and the desired argument format using the "format" key. The available formats are "scalar" and "array". Using the "array" format will incur a performance penalty but may be more convenient in some situations.
my $template = HTML::Template->new(filename => 'zap.tmpl',
filter => { sub => $filter,
format => 'array' });
You may also have multiple filters. This allows simple filters to be combined for more elaborate functionality. To do this you specify an array of filters. The filters are applied in the order they are specified.
my $template = HTML::Template->new(filename => 'zap.tmpl',
filter => [
{ sub => \&decompress,
format => 'scalar' },
{ sub => \&remove_spaces,
format => 'array' }
]);
The specified filters will be called for any TMPL_INCLUDEed files just as they are for the main template file.
"param()" can be called in a number of ways
1) To return a list of parameters in the template :
( this features is distinct in HTML::Template::Pro:
it returns a list of parameters _SET_ after new() )
my @parameter_names = $self->param();
2) To return the value set to a param :
my $value = $self->param('PARAM');
3) To set the value of a parameter :
# For simple TMPL_VARs:
$self->param(PARAM => 'value');
# with a subroutine reference that gets called to get the value
# of the scalar. The sub will receive the template object as a
# parameter.
$self->param(PARAM => sub { return 'value' });
# And TMPL_LOOPs:
$self->param(LOOP_PARAM =>
[
{ PARAM => VALUE_FOR_FIRST_PASS, ... },
{ PARAM => VALUE_FOR_SECOND_PASS, ... }
...
]
);
4) To set the value of a a number of parameters :
# For simple TMPL_VARs:
$self->param(PARAM => 'value',
PARAM2 => 'value'
);
# And with some TMPL_LOOPs:
$self->param(PARAM => 'value',
PARAM2 => 'value',
LOOP_PARAM =>
[
{ PARAM => VALUE_FOR_FIRST_PASS, ... },
{ PARAM => VALUE_FOR_SECOND_PASS, ... }
...
],
ANOTHER_LOOP_PARAM =>
[
{ PARAM => VALUE_FOR_FIRST_PASS, ... },
{ PARAM => VALUE_FOR_SECOND_PASS, ... }
...
]
);
5) To set the value of a a number of parameters using a hash-ref :
$self->param(
{
PARAM => 'value',
PARAM2 => 'value',
LOOP_PARAM =>
[
{ PARAM => VALUE_FOR_FIRST_PASS, ... },
{ PARAM => VALUE_FOR_SECOND_PASS, ... }
...
],
ANOTHER_LOOP_PARAM =>
[
{ PARAM => VALUE_FOR_FIRST_PASS, ... },
{ PARAM => VALUE_FOR_SECOND_PASS, ... }
...
]
}
);
Sets all the parameters to undef. Useful internally, if nowhere else!
output() returns the final result of the template. In most situations you'll want to print this, like:
print $template->output();
When output is called each occurrence of <TMPL_VAR NAME=name> is replaced with the value assigned to "name" via "param()". If a named parameter is unset it is simply replaced with ''. <TMPL_LOOPS> are evaluated once per parameter set, accumulating output on each pass.
Calling output() is guaranteed not to change the state of the Template object, in case you were wondering. This property is mostly important for the internal implementation of loops.
You may optionally supply a filehandle to print to automatically as the template is generated. This may improve performance and lower memory consumption. Example:
$template->output(print_to => *STDOUT);
The return value is undefined when using the "print_to" option.
This method is not supported in HTML::Template::Pro.
The main reason for small incompatibilities between HTML::Template and HTML::Template::Pro is the fact that HTML::Template builds parsed tree of template before anything else. So it has an additional information which HTML::Template::Pro obtains during output.
In cases when HTML::Template dies, such as no_includes, bad syntax of template, max_includes and so on, HTML::Template::Pro issues warning to STDERR and continue.
the following options are not supported in HTML::Template::Pro:
vanguard_compatibility_mode.
The options die_on_bad_params and strict are ignored.
HTML::Template::Pro behaves itself as HTML::Template called with
die_on_bad_params => 0, strict => 0.
It currently can't be changed, because HTML::Template::Pro can't know whether a parameter is bad before it start output. This may change in future releases.
To keep backward compatibility with HTML::Template, you should explicitly call its new() with die_on_bad_params => 0, strict => 0.
This method is not supported in HTML::Template::Pro.
param() without arguments should return a list of parameters in the template. In HTML::Template::Pro it returns a list of parameters set after new().
With case_sensitive and loop_context_vars the special loop variables should be available in lower-case only.
associate is case_sensitive inside loops.
When submitting bug reports, be sure to include full details, including the VERSION of the module, a test script and a test template demonstrating the problem!
To define a new function, pass a "functions" option to new:
$t = HTML::Template::Pro->new(filename => 'foo.tmpl',
functions =>
{ func_name => \&func_handler });
or
$t = HTML::Template::Expr->new(filename => 'foo.tmpl',
functions =>
{ func_name => \&func_handler });
Or, you can use "register_function" class method to register the function globally:
HTML::Template::Pro->register_function(func_name => \&func_handler); or HTML::Template::Expr->register_function(func_name => \&func_handler);
You provide a subroutine reference that will be called during output. It will receive as arguments the parameters specified in the template. For example, here's a function that checks if a directory exists:
sub directory_exists {
my $dir_name = shift;
return 1 if -d $dir_name;
return 0;
}
If you call HTML::Template::Expr->new() with a "functions" arg:
$t = HTML::Template::Expr->new(filename => 'foo.tmpl',
functions => {
directory_exists => \&directory_exists
});
Then you can use it in your template:
<tmpl_if expr="directory_exists('/home/sam')">
This can be abused in ways that make my teeth hurt.
"register_function()" can be called in a number of ways
1) To fetch the names of registered functions in the template:
list of function's that set _after_ or _in_ new():
my @registered_functions_names = $self->register_function();
my @all_avalible_functions_names =
HTML::Template::Pro->register_function();
2) To fetching the function by name:
my $function = $self->register_function('FUNCTION_NAME');
3) To set a new function:
# Set function, that can be called in templates, wich are processed
# by the current object:
$self->register_function(foozicate => sub { ... });
# Set global function:
HTML::Template::Pro->register_function(barify => sub { ... });
for details of "how to defined a function" see in "EXPR: DEFINING NEW FUNCTIONS".
"register_function" class method can be called in mod_perl's startup.pl to define widely used common functions to HTML::Template::Expr. Add something like this to your startup.pl:
use HTML::Template::Pro;
HTML::Template::Pro->register_function(foozicate => sub { ... });
HTML::Template::Pro->register_function(barify => sub { ... });
HTML::Template::Pro->register_function(baznate => sub { ... });
HTML::Template::Pro does not forces the HTML::Template global_vars option to be set, whereas currently HTML::Template::Expr does. Anyway, this also will hopefully go away in a future version of HTML::Template::Expr, so if you need global_vars in your templates then you should set it explicitly.
to Sam Tregar, sam@tregar.com
Original credits of HTML::Template:
This module was the brain child of my boss, Jesse Erlbaum ( jesse@vm.com ) at Vanguard Media ( http://vm.com ) . The most original idea in this module - the <TMPL_LOOP> - was entirely his.
Fixes, Bug Reports, Optimizations and Ideas have been generously provided by:
Richard Chen Mike Blazer Adriano Nagelschmidt Rodrigues Andrej Mikus Ilya Obshadko Kevin Puetz Steve Reppucci Richard Dice Tom Hukins Eric Zylberstejn David Glasser Peter Marelas James William Carlson Frank D. Cringle Winfried Koenig Matthew Wickline Doug Steinwand Drew Taylor Tobias Brox Michael Lloyd Simran Gambhir Chris Houser <chouser@bluweb.com> Larry Moore Todd Larason Jody Biggs T.J. Mather Martin Schroth Dave Wolfe uchum Kawai Takanori Peter Guelich Chris Nokleberg Ralph Corderoy William Ward Ade Olonoh Mark Stosberg Lance Thomas Roland Giersig Jere Julian Peter Leonard Kenny Smith Sean P. Scanlon Martin Pfeffer David Ferrance Gyepi Sam Darren Chamberlain Paul Baker Gabor Szabo Craig Manley Richard Fein The Phalanx Project Sven Neuhaus
Thanks!
Original credits of HTML::Template::Expr:
The following people have generously submitted bug reports, patches and ideas:
Peter Leonard Tatsuhiko Miyagawa
Thanks!
You can find information about HTML::Template::Pro at:
http://html-tmpl-pro.sourceforge.net
You can find information about HTML::Template and other related modules at:
http://html-template.sourceforge.net
Sam Tregar, sam@tregar.com (Main text)
I. Vlasenko, <viy@altlinux.org> (Pecularities of HTML::Template::Pro)
HTML::Template : A module for using HTML Templates with Perl Copyright (C) 2000-2002 Sam Tregar (sam@tregar.com) This module is free software; you can redistribute it and/or modify it under the terms of either: a) the GNU General Public License as published by the Free Software Foundation; either version 1, or (at your option) any later version, or b) the "Artistic License" which comes with this module. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See either the GNU General Public License or the Artistic License for more details. You should have received a copy of the Artistic License with this module, in the file ARTISTIC. If not, I'll be glad to provide one. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
| 2022-10-19 | perl v5.36.0 |