Expanding variables inside the CGI module

filmo has asked for the wisdom of the Perl Monks concerning the following question:

All right, (a) I'm new at this. Nuff said. (b) I've looked in the CGI pod but didn't see an explaination. So, the question. I'm trying to expand a variable inside of a "param" call.

sub Handle_Media {
   my $name = shift;
   my @Files = $q->param("$name_files");  
   my @Delete = $q->param("$name_DEL");   
   more code here...
[download]

Thus, if I pass "LIBRARY" to the subroutine, I want to get all the values that are in the "LIBRARY_files" param and in the "LIBRARY_DEL" param. If I simply put my @Files = $q->param("LIBRARY_files"); I get the list like I expected, so I know the param exists and has data in it. However, I need for this routine to be variable instead of fixed. I'm sure I must be missing something simple Thanks in advance. -- Filmo the Klown

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Re: Expanding variables inside the CGI module by mirod (Canon) on Mar 03, 2001 at 13:40 UTC
I think your problem is that `$name_files` is interpreted as the name of a variable. You need to use either `"$name\_files"` or `"${name}_files"` or `$name . '_files'` so that the Perl interpreter knows what's part of the variable name and what's a string. If you had used `use strict` as you should _ALWAYS_ do, you would have gotten an error as the `$name_files` variable does not exist.	[reply]
Re: Expanding variables inside the CGI module by mr.nick (Chaplain) on Mar 03, 2001 at 20:53 UTC
A simpler answer to your question is best describe with this example :): `sub Handle_Media { my $name = shift; my @Files = $q->param($name."_files"); my @Delete = $q->param($name."_DEL"); ## more }` [download] Which is probably what you wanted, yes? still ... asleep ... must ... coffee ...	[reply] [d/l]
Re: Re: Expanding variables inside the CGI module by filmo (Scribe) on Mar 04, 2001 at 01:12 UTC
Many thanks, mr.nick's was exactly what I'm looking for. Seems so obvious now, but isn't that always the case. And yes, I'm learning to use STRICT... -- Filmo the Klown	[reply]
(boo) Re: Expanding variables inside the CGI module by boo_radley (Parson) on Mar 03, 2001 at 20:37 UTC
I suggest using the `import_names` feature of CGI, rather than trying to hack your way to something similar, but not quite as good. from CGI's POD : `IMPORTING ALL PARAMETERS INTO A NAMESPACE: $query->import_names('R'); This creates a series of variables in the 'R' namespace. For example, $R::foo, @R:foo. For keyword lists, a variable @R::keywords will appear. If no namespace is given, this method will assume 'Q'. WARNING: don't import anything into 'main'; this is a major security risk!!!!` pretty simple, huh? Just by putting `$q->import_names` just before you need to query them, you now have access to @Q::LIBRARY_files, @Q::BAKERY_files, @Q::HOSPITAL_files, or whatever else your CGI generates. If the 'Q' namespace isn't descriptive enough, you can `$q->import_names("All_my_Parameters")` and you'll have @All_my_Parameters::LIBRARY_files, and so on. Hope that helps.	[reply] [d/l] [select]