"mod_perl Developer's Cookbook" by Geoffrey Young, Paul Lindner,
and Randy Kobes which was first printed by Sams Publishing in
January 2002 is a much-awaited addition to the
few existing books
which are exclusively about mod_perl.
mod_perl is the bridge that empowers Perl
and Apache users with the full strength of the Perl
programming language and the Apache web server.
The primary author, Geoffrey Young is an active member of
the mod_perl community and has written modules
such as Apache::Clean,
and Apache::Dispatch amongst others which
can be found on
(Comprehensive Perl Archive Network, a large collection of
Perl modules and documentation). Co-authors Paul Lindner, an
and Randy Kobes, a
professor of physics
at the University of Winnipeg in Canada, both use
mod_perl extensively and have contributed
modules such as
to CPAN. The latter is no stranger to Perl books as he has
"Perl Developer's Toolkit"
"Professional Perl Development"
in addition to implementing a
CPAN search engine.
Perl developers who want to create Web applications by harnessing
the flexibility of Apache, and mod_perl enabled
Apache web site administrators are the target audience of this book.
Meanwhile, the authors intended it to be a practical, hands-on
reference guide containing working, real-world examples. All
examples use perl 5.6.1, Apache 1.3.22, and
mod_perl 1.26 built with all supported options
This 650-page book has 17 chapters and 3 appendixes, grouped
under three main parts - Part I covers installing and
configuring mod_perl, Part II covers the
mod_perl API, and Part III covers each of
the Apache directives provided by mod_perl.
The essence of each part is summarised at the start before
moving on to the individual chapters. Each chapter begins
with an introduction, is then followed by subsections referred
to in the book as recipes. Each recipe is for a specific task
or problem and has the following format - it states the
objective of the task in just one sentence, proceeds to
provide the code for the task under the "Technique" subsection,
and then explains what the code does under the "Comments"
subsection. There are a total of 192 recipes.
Chapter 1 and 2 which are under Part I start off with the
basics of installing mod_perl by using
various methods from using a binary version to building it
statically or as a DSO (Dynamic Shared Object) module from
source on an assortment of platforms which include Linux,
Solaris, Microsoft Windows, and Mac OS X. It then talks about
how to configure the Apache httpd.conf file to make use of
mod_perl which has just been installed.
Part II can be considered the section where you learn the
theory of the fundamentals of Apache and
mod_perl API. It explains how Apache processes
requests in a series of phases, delves into how by using
mod_perl, Perl code could be executed during
any of these phases, and talks about how the
mod_perl API corresponds to them. It shows
you how to access the Apache request, server, and connection
records, manipulate all the fields in them, looks at how
Apache handles file operations, and teaches you how to write,
test, debug, fine-tune, configure, package, and distribute
your own mod_perl handler. The last chapter
in this section explains about mod_perl's
Part III is where you apply what you have learned in the
previous section in real world problems. It illustrates how
mod_perl handlers can be used within each
of the Apache phases, and shows how the
mod_perl API fits into each of the Apache
phases with a nice diagram. The seven chapters under this
segment explain in detail about each mod_perl
Perl*Handler directive and provide
scenarios where they can be used. Lastly, appendix A lists
all the mod_perl hooks and build options,
appendix B lists the constants to be used in
mod_perl API programming, and appendix C
has quite a complete list of resources followed by the index.
Overall, this is a good reference book as the source code
samples make up 50% of the content so you can readily customise
them to meet your requirements. The commentaries are easy to
understand as they are written in a simple, narrative, and
lucid style despite the numerous technical terms used. However,
it could use more diagrams to illustrate complex concepts as
currently flow charts, diagrams, and screen shots are used
sparingly but effectively to simplify abstract ideas.
In my opinion, the best way to make full use of this book is
to skim through the whole book and read only the the
introduction of each part and chapters, and then the objective
of each recipe. Then go back to the recipe that interests you
most and study the sample code while digesting the explanation
provided under the "Comments" subsection so that you may write
your own Perl module using the code as a guideline.
Although this book is aimed at all Perl developers, beginners
may find it difficult to grasp the concepts. The objective of
the recipes can be quite distinct at times and this can disrupt
the continuity and logical thought process of beginners as
they move from one recipe to another sequentially. As a result,
the mod_perl novice may find it difficult to
gather their thoughts and digest the wealth of information
provided. Therefore I find that Sams Publishing has correctly
categorised this book under "User Level: Intermediate-Advanced".
It is undeniable that those who are not familiar with Apache's
API and mod_perl at all will be totally lost
and drowning in this sea of recipes because in order for one
to be able to whip up a tasty meal by using a cookbook as a
guide, one must be able to identify and obtain the ingredients
of the recipe beforehand.
To be fair, the authors did recommend that readers use this
"Writing Apache Modules with Perl and C"
by Lincoln Stein and Doug MacEachern, and
the online mod_perl Guide
by Stas Bekman to achieve better understanding. The authors
also state that they assume and I quote them here: "that
the reader has a good background in Perl, a fair understanding
of Apache, and understands the basic concepts of building a
Web application, Web protocols, and HTML, and in some of the
more complex examples we may assume a level of mastery that
exceeds the typical audience.".
Although the authors cautioned that this book is by no means
comprehensive, I would say that this book is as close as a
book can get to become the bible of mod_perl
so if you are really serious about mod_perl,
then get it by all means! It may set you back nearly 30 pounds
(USD40) but it is well worth-it. Even if you
are a beginner, eventually you will find this book useful
after you are through with all the online
mod_perl guides and documentation. Experts
will have fun jumping right in, going through the recipes
and rediscovering the joy of finding a dish that they have
not tasted before.
For a taste of the meals yourself, you may drop in and pay
a visit to its
where you can read through the
table of contents
You may also wash, cut, chop, mix, bake, stir, whip, roast,
steam, sprinkle, stir-fry, fry, pinch, rinse, barbecue, eat,
drink, and swallow your way through its source code repository,
errata, and other resources provided. Enjoy!