It covers everything from basic network programming to multiplexing, threading and forking for high loads.

It also covers 'daemonizing', logging and other stuff you probably want to do.

In short: A perl program can perform well under high loads, it can even perform better than stuff written in other languages.
I'm longing to hear Marc Lehmans talk at German Perl Workshop, why he wrote his own web server for very high loads that couldn't be served by apache and thttp.

I picked up a copy at lunch since my next project involves a networked perl daemon. I'm only a couple hours into the book, but am quite impressed so far.

On a side note, merlyn benchmarked a trivial http-redirector written in perl at nearly 10x the throughput of apache. See his comments in this thread for details.

-Blake

Absolutely true. This book walks through this exact topic in detail and refines it to the point where you just use the modules you have written for daemons. Not only that but you will understand the modules quite well.

"Nothing is sure but death and taxes" I say combine the two and its death to all taxes!

--
Ilya Martynov (http://martynov.org/)

I forgot to add that I would not write MTA which listens to SMTP port. I don't trust myself to do it in proper, secure, DOS resistant way. Instead I would plug script written with usage of pperl into some "real" MTA like postfix or sendmail. Such script still is subject for security compromises but their changes are lower since your script would be simplier (thus lower probability of security holes) and it would handle only portion of possible attacks.

--
Ilya Martynov (http://martynov.org/)

I would whole-heartedly concur with this approach - In addition to minimising the work of the script author to write a robust and ruggedly network process, this approach would allow the program to be called 'as-needed' rather than as a daemon process.

Written as a plug-in to a more thoroughly tested and widely used MTA, the script could be called through an /etc/mail/aliases type of pipe such as:

test:          "|/usr/local/bin/myscript"
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With the corresponding script able to process mail received via reading STDIN. eg.

#!/usr/bin/perl -T

use strict;

undef $/;
my $message = <>;
my ($headers, $body) = split(/\n\n/, $message, 2);
$headers =~ s/\n\s+/ /g;

foreach (split(/\n/, $headers)) {
    # ... process headers ...
}
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An excellent suggestion IlyaM++

 

perl -e 's&&rob@cowsnet.com.au&&&split/[@.]/&&s&.com.&_&&&print'

use POSIX qw/setsid/;
sub daemonise
{
    my ($self) = @_;
    chdir('/') or die "Can't chdir to /: $!";
    open STDIN, "</dev/null";
    defined(my $pid = fork) or die "Can't fork: $!";
    exit if $pid;
    setsid();
    $SIG{HUP} = \&hup_handler($self); # you need to define this
   # we store our pid's for shutdown
    if ( $self->{pidfile} ) {
     open PIDFILE, "> " . $self->{pidfile};
     print PIDFILE "$$\n";
     close PIDFILE;
    }
}
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