Programming Troubles

Johnny Quags posted this at 23:19 — 3rd December 1999.

They have: 2 posts

Joined: Dec 1999

Hi,
Well I hear this is a good place to go with programming troubles. I am having a problem with one script. The script is being used to track a referring urls for orders and it works great except now the guy I made it for wants templates so he can easily edit. Here is my base for the new files.

#!/usr/bin/perl
$ref=$ENV{'QUERY_STRING'};
open (FILE,"colo.txt");
@form=<FILE>;
close(FILE);
print "Content-type: text/html\n\n";
print<<EOF;
@form
EOF
exit;

That is the page code and it does work but when it opens the text file it prints
$ref (I actually put the $ref in the text files)
not the actual referring url.
Any ideas?
Thanks

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Clueless in cyberspace

Rob Pengelly posted this at 18:06 — 4th December 1999.

They have: 850 posts

Joined: Jul 1999

What does each line of the text file look like?

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The longest recorded flight of a chicken is 13 seconds.

sumengen posted this at 13:58 — 5th December 1999.

They have: 15 posts

Joined: Jun 2000

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

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japhy posted this at 04:10 — 13th December 1999.

They have: 161 posts

Joined: Dec 1999

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

fairhousing posted this at 05:53 — 13th December 1999.

They have: 1,587 posts

Joined: Mar 1999

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 posted this at 08:23 — 13th December 1999.

They have: 161 posts

Joined: Dec 1999

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