August 1998
Intermediate to advanced
800 pages
39h 20m
English
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Creating HTML Templates
Problem
You want to store a parameterized template in an external file, read it in from your CGI script, and substitute your own variables for escapes embedded in the text. This way you can separate your program from the static parts of the document.
Solution
To expand only variable references, use this
template function:
sub template {
my ($filename, $fillings) = @_;
my $text;
local $/; # slurp mode (undef)
local *F; # create local filehandle
open(F, "< $filename\0") || return;
$text = <F>; # read whole file
close(F); # ignore retval
# replace quoted words with value in %$fillings hash
$text =~ s{ %% ( .*? ) %% }
{ exists( $fillings->{$1} )
? $fillings->{$1}
: ""
}gsex;
return $text;
}On a data file like this:
<!-- simple.template for internal template() function --> <HTML><HEAD><TITLE>Report for %%username%%</TITLE></HEAD> <BODY><H1>Report for %%username%%</H1> %%username%% logged in %%count%% times, for a total of %%total%% minutes.
Or use the CPAN module Text::Template to expand full expressions if you can guarantee the data file is secure from tampering. A data file for Text::Template looks like this:
<!-- fancy.template for Text::Template -->
<HTML><HEAD><TITLE>Report for {$user}</TITLE></HEAD>
<BODY><H1>Report for {$user}</H1>
{ lcfirst($user) } logged in {$count} times, for a total of
{ int($total / 60) } minutes.Discussion
Parameterized output for your CGI scripts is a good idea for many reasons. Separating your program from its data lets you give other ...