Network Programming with Perl

Author: Lincoln D. Stein



Publisher: Addison-Wesley

Reviewed by: Simon Wistow

Any book that gets a glowing review from Jon Orwant can't be all bad. Plus at 20 odd quid ($39.99) for a 700+ page book you get good LART value too. But what's it like as a Networking guide?

Well, in a word, excellent. Neatly separated into 4 sections (Basics, Developing Clients for Common Services, Developing TCP Client/Server systems and Advanced Topics) the book picks its way neatly around the minefield that is trying to be a reference book and a tutorial simultaneously.

The first section starts off with an introduction to networking and how it pertains to Perl and then provides a useful example of how the IO::* modules make shifting from local files to remote files is easy.

        #!/usr/bin/perl -w

        use strict;
        use IO::File;

        my $file = shift;
        my $fh   = IO::File->new($file);
        my $line = %gt;$fh<;
        print $line;

goes to

        #!/usr/bin/perl -w

        use strict;
        use IO::Socket;

        my $server = shift;
        my $fh     = IO::Socket::INET->new($server);
        my $line   = %gt;$fh<;
        print $line;

for example.

It then goes on to explain about pipes, processes and signals, tutors on Berkley sockets and the TCP protocol and then a more in depth look at the IO::Socket API.

All of this is presented as an easily readable, well paced tutorial which functions as an excellent reference guide.

The second section goes on to deal with common clients such as FTP, Telnet, Mail (POP, IMAP and SMTP) and web clients including a complete news to mail gateway.

The third section is probably the best despite the fact that it could easily have been the worst. It begins by explaining how to write a forking sever and using the inetd daemon and then gradually ramps up the complexity going into, in turn, multithreaded servers, multiplexed servers, nonblock I/O, bulletproofing, pre forking and threading and non-blocking TCP clients using IO::Poll.

Again, each stage is clearly explained and the drawbacks of each method are laid out in an easy to understand manner.

The final section, on Advanced Topics, seems daunting at first but by the time you've read the first three chapters they seem like a natural progression. It deals with topics that you normally won't have to deal with but which are useful for those odd moments when you really do need to know about TCP urgent and out of band data. Oddly, UDP is counted as an advanced topic along with broadcasting, multicasting and UNIX domain sockets but hey ho.

There's also a load of source code including a Markov Chain-a-like called Text::Travesty.

Which is nice.

All in all, a nice book, two thumbs up, highly recommended, fun for all the family. Although perfect binding might have been nice :)