Wie erstelle ich eine 'Bitte Warten'-Seite?

Problem

Lösung

#!/usr/bin/perl

# background.pl
# Aufruf: http://server/background.pl?w=create;count=5

use strict;
use warnings;
use CGI;
use Fcntl qw(:flock);

my $cgi = CGI->new;
my $url = "http://server/background.pl";
                                                         
my $w = $cgi->param('w') || 'show';
if ($w eq 'show') {
    show($cgi);
}
elsif ($w eq 'create') {
    create($cgi);
}

sub create {
    my ($cgi) = @_;
    my $val = $cgi->param('count') || 5;
    if ($val =~ tr/0-9//c or $val > 10) {
        $val = 5;
    }
    my $id = time() . $$;
    my $filename = "background.id$id";
    $SIG{CHLD} = 'IGNORE';
    if (my $pid = fork) {
        # parent
        print $cgi->redirect("/background.pl?w=show;id=$id");
        close STDOUT;
        close STDERR;
        close STDIN;
        exit;
    }
    else {
        open my $fh, ">", $filename or die $!;
        flock $fh, LOCK_EX;
        close STDOUT;
        close STDERR;
        close STDIN;
        for my $i (1 .. $val) {
            print $fh "$i\n";
            sleep 2;
        }
        close $fh;
        exit;
    }
}

sub show {
    my ($cgi) = @_;
    my $id = $cgi->param('id') || '';
    $id =~ tr/0-9//cd;
    print $cgi->header;
    if (length $id > 20) {
        print $cgi->start_html;
        print "too long";
    }
    else {
        my $filename = "background.id$id";
        my $meta = $cgi->start_html(
            my $meta_refresh =
            -head => $cgi->meta(
                {
                    -http_equiv => 'refresh',
                    -content    => "2; $url?w=show;id=$id",
                }
            ));
        if (open my $fh, "<", $filename) {
            my $lock = flock $fh, LOCK_EX|LOCK_NB;
            if ($lock) {
                # success, got lock
                my $output = do { local $/; <$fh> };
                print "Result: $output";
            }
            else {
                print $meta;
                print "Not finished";
            }
            close $fh;
        }
        else {
            print $meta;
            print "File not yet created";
        }
    }
    print $cgi->end_html;
}

Ergänzungen, Kommentare

---+++ Main.??? - 14 Jul 2003 - Betreff