japhy — Mon, 13 Dec 1999 08:23:00 +0000

The aim of this thread is to discuss how to expand variables in templates; fairhousing, your reply opens the file for READING (and thus, you can't write $ref to it), and it doesn't accomplish what was first asked.

There are several Perl modules available that allow for text templates to have variables expanded in them. The method I usually use is this: in my text file, I'll have something like:

code:

Hello, %%name%%.  Today is %%date%%.
You've accessed this quiz %%num%% times.[/code]

Then, in my Perl program, I'll have the following code:

code:#!/usr/bin/perl -w

use CGI;
use CGI::Carp qw( fatalsToBrowser );
use strict;

my $q = new CGI;

open TPL, "templates/welcome.tpl" or
  die "can't open templates/welcome.tpl: $!";
while (<TPL> ) {
  s/%%([^%]+)%%/$q->param($1)/eg;
  print;
}
close TPL;[/code]

Let me explain the finer points of this example.  By placing the sections of the template I want replaced between %%'s, I can separate them and be sure I'm replacing ONLY the text I want.  The regular expression of s/%%([^%]+)%%/$q->param($1)/eg does quite a bit of work.  The left hand side means "match two %'s, then any number of NON-% characters, and then two %'s; store the non-% characters in $1."  The right hand side gets the value of this template key, "name", "date", or "num", for instance, and gets its value from the CGI query.

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MIDN 4/C PINYAN, NROTCURPI, USNR

fairhousing — Mon, 13 Dec 1999 05:53:00 +0000

here's some very simple code that may do what u want.

code:

#!/usr/bin/perl 
$ref=$ENV{'QUERY_STRING'}; 
open (FILE,"colo.txt");
print FILE "$ref";
close(FILE);
exit;
[/code]



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japhy — Mon, 13 Dec 1999 04:10:00 +0000

If I understand you correctly, you have a text file containing something like:

<html>
<body>
Query string is $ref
</body>
</html>

Your program sets the $ref variable, and when you print the contents of the file, you want the '$ref' in the file to be interpolated as the $ref variable's value.

It would be quite efficient like so:

#!/usr/bin/perl -w

use CGI::Carp qw( fatalsToBrowser );
use strict;
my $ref = $ENV{QUERY_STRING};

print "Content-type: text/html\n\n";

open FILE, "filename.txt" or
die "can't open filename.txt: $!";
while (<FILE> ) {
s/\$ref/$ref/g;
print;
}
close FILE;

CGI::Carp::fatalsToBrowser sends error messages to the browser, like the die() message, if the file can't be opened.

The regular expression, s/\$ref/$ref/g, changes every occurrence of '$ref' to the value of the $ref variable for the current line of text (that what the /g does -- makes the substitution global).

print without any arguments prints the $_ variable, which is set to each line of FILE from the while-loop.

For more info, look at the following documentation: perlre (for regular expressions), perlfaq4 (for expanding variables in text strings). That information can also be accessed in the following ways:

perldoc perlre

perldoc -q text strings
# or
perldoc perlfaq4

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--
MIDN 4/C PINYAN, NROTCURPI, USNR

sumengen — Sun, 05 Dec 1999 13:58:00 +0000

Hi,
You mention writing $ref to the file?? The code doesn't seem to do that.

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Rob Pengelly — Sat, 04 Dec 1999 18:06:00 +0000

What does each line of the text file look like?

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The longest recorded flight of a chicken is 13 seconds.