I have a cgi script that takes a while to process some information, so I'd like to write a 'Please wait' message to the browser while the script processes. I have a little .gif that spins to show the user we're processing their request. Searched the web and found some ideas, but it is this little spinner that is the issue... none of what I found seems to allow the spinning object to do just that -- spin.
Some sample code that hopefully explains what I'm trying to do...
When I get the spinning object to display -- the code looks like this:
## Main
{
my $q = new CGI;
if(my $pid = fork ) { # parent
print $q->header( -type => "text/html",
),
$q->start_html( -class => 'parent',
-title => 'Please Wait',
),
$q->start_form( -method => 'get',
-name => 'form1',
),
'<center>',
$q->p( 'Please wait while we collect requested data' ),
$q->br x 2,
"<img id='spinner' class='spinner' name='spinner' src='/images/spinner.gif' alt='' />",
'</center>',
$q->end_form,
$q->end_html;
}
elsif(defined($pid)) { # child
sleep(10);
print $q->header( -type => "text/html",
),
$q->start_html( -class => 'child',
-title => 'Child Page',
),
$q->start_form( -method => 'get',
-name => 'form1',
),
'<center>',
$q->p( 'Print my child -- print.'),
$q->br x 2,
'</center>',
$q->end_form,
$q->end_html;
exit 0;
}
else { # uh oh
die "Cannot fork.";
}
exit;
}
For actually printing the output from the child to the browser:
## Main
{
my $q = new CGI;
if(my $pid = fork ) { # parent
print $q->header( -type => "text/html",
),
$q->start_html( -class => 'parent',
-title => 'Please Wait',
),
$q->start_form( -method => 'get',
-name => 'form1',
),
'<center>',
$q->p( 'Please wait while we collect requested data' ),
$q->br x 2,
"<img id='spinner' class='spinner' name='spinner' src='/images/spinner.gif' alt='' />",
'</center>',
$q->end_form,
$q->end_html;
waitpid($pid,0);
}
elsif(defined($pid)) { # child
sleep(10);
print $q->header( -type => "text/html",
),
$q->start_html( -class => 'child',
-title => 'Child Page',
),
$q->start_form( -method => 'get',
-name => 'form1',
),
'<center>',
$q->p( 'Print my child -- print.'),
$q->br x 2,
'</center>',
$q->end_form,
$q->end_html;
exit 0;
}
else { # uh oh
die "Cannot fork.";
}
exit;
}
So sample #1 above will write my 'Please wait' message complete with an actively spinning object, but I never get the child's output written to the browser; and sample #2 above will write the output from the child, but I get no neat spinning object before the child's output. I know the problem lies somewhere in the realm of not being able to rewrite to the browser (meaning I have to redirect or submit somehow), but I'm not sure exactly how to get where I need to go. Forking seemed to be the a solution, but I'm obviously missing something here.
Any help would be appreciated.
perl: 5.8.5
CGI: 3.29
OS: Linux <hostname> 2.6.9-55.EL #1 Fri Apr 20 16:35:59 EDT 2007 i686 athlon i386 GNU/Linux
