All:
*** BE CAREFUL ***
Examine the following code from a single ASP script:
<%
my $mainvariable = $Session->{mysessionvar}; #as an example.
$Response->write( Mylocalsub() );
sub Myloccalsub{
return $mainvariable;
}
%>
The subroutine "Mylocalsub" simply returns a variable originally set in the
main script. One (at least naive me!) naturally assumed that Mylocalsub
will ALWAYS use the value set at the top of the script. Heck - the variable
and the subroutine are in the same file!
NOT! When multiple sessions are working the same $Application across
several processes, I have found that "Mylocalsub" often uses "$mainvariable"
from a different session! I believe that because of how "Mylocalsub" gets
compiled into the application namespace, $mainvariable in "Mylocalsub"
points to the "$mainvariable" of the first-to-be-started session.
Subsequent sessions will display the session data of the first person to get
in!
Because of how the scripts gets compiled (and how DynamicIncludes is set),
$Response->Include behaves the same as above. I do not think that it is
wise to write code dependent on the setting of DynamicIncludes.
I believe that this is one of several "mod_perl things" and that most
problems are caught with "use strict;" However, the example above is not,
and it is a tricky bug to track down.
One possible fix:
<%
$Response->write( &Mylocalsub($mainvariable) );
#with appropriate fixes to Mylocalsub still required.
or
$Response->Include( "mylocalsub.inc", $mainvariable ); #if using Includes!
%>
The lesson:
DO NOT DEPEND ON GLOBAL VARIABLES. ALWAYS PASS DATA TO SUBROUTINES VIA AN
ARGUMENT LIST. (Or set appropriate variables in the "Script_OnStart" or
store important stuff in the $Session.)
JL
> -----Original Message-----
> From: Philip Mak [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, September 12, 2001 4:46 PM
> To: Tim Pushor
> Cc: [EMAIL PROTECTED]
> Subject: Re: Includes revisited
>
>
> On Wed, 12 Sep 2001, Tim Pushor wrote:
>
> > When I use $Response->Include('filename'), does this script execute as
> > a perl block or something? I notice that local variables are not
> > visible inside the included file:
>
> If you want Apache::ASP to be more liberal about Globals, you can do
> "PerlSetVar DynamicIncludes 0" in your httpd.conf, and always use the
> <!--#include file="..."--> syntax instead of $Response->Include. This is
> not very efficient if the included files are used in many different
> scripts, because then it must be compiled separately each time. But it
> will put the include files inside the same namespace, allowing you to use
> global variables freely.
>
>
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