Practical mod_perl

honestpuck writes with the review below of O'Reilly's Practical mod_perl, which he describes as "a doorstop sized volume that provides more information on using mod_perl than you ever thought you needed." Read on for the rest of his review, and to see whether you actually do need to know what's in this book. Practical mod_perl author Stas Bekman & Eric Cholet pages 858 publisher O'Reilly rating 8 - Good book, some flaws reviewer Tony Williams ISBN 0596002270 summary Good overall guide for running and developing with mod_perl

The almost 900 pages are divided into five parts and a bunch of appendices. Part I, "mod_perl Administration" covers building, configuring and installing mod_perl, followed by some Apache details and an 80-page guide to coding with mod_perl in mind. Part II, 'mod_perl Performance' deals with ways of getting the best out of Apache and mod_perl, with a little about security. Part III deals with databases, including persistent connections and data sharing. Part IV is a great guide to debugging and troubleshooting. Part V is a brief look at Apache 2 and mod_perl 2.

The appendices are useful. The first is a short section of around a dozen small 'recipes' for performing various tasks using mod_perl. I found these a good base for more complex tasks, particularly when combined with examples from elsewhere in the book. The second is a list of Perl modules that extend Apache and mod_perl with a brief description of each. The third gives some strategies for providers wanting to host Apache with mod_perl. The fourth and fifth give good overviews of the Template Toolkit and AxKit, an XML application server built on mod_perl.

The book is readable, tending towards heavy writing and certainly dense, but I didn't feel this was a problem in a book meant for a fairly advanced audience. I think you'd want to be a fairly good Perl programmer and well versed in Apache before needing this volume and shouldn't expect to be spoon fed. I thought it well written.

In a book of this size you expect to find a lot of example code, and you won't be disappointed. The book is peppered with short Perl examples and example command lines and configurations, all well explained. The one shortcoming is that there aren't many examples of full-blown applications where you can see everything discussed and have it explained all in one place. I would have appreciated some more of this, the examples tend to be on the short side.

This book sits well in the marketplace. It provides more details on running, installing and configuring mod_perl and Apache than mod_perl Developer's Cookbook (and also delves more into the reasons for doing something one particular way and much more help on debugging), though the Developer's Cookbook becomes a good companion to this volume as it provides a lot more in the way of examples. For those that want to get deep into the high end of mod_perl there is Writing Apache Modules in Perl and C, which is at core a good book on high end mod_perl programming.

O'Reilly have their usual website with Table of Contents, an example chapter, and errata. The authors have their own website with some of the same information and all the code examples from the book as both individual files and one 40k tarball.

I would recommend this book to anyone who administers and writes for mod_perl, it fills the missing pieces in mod_perl Developers Cookbook and is a good companion volume to it.

You can purchase Practical mod_perl from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

Comments

thanks--

[garysears]

Thank you for the review.

There. Isn't a little common courtesy refreshing?

Re:Is there anything in there...

[consumer]

There are several things that can stop apache children from growing out of control, and yes, they are documented in the book. One thing that helps is the use of modules like Apache::SizeLimit and Apache::ResourceLimit. Another thing that helps is using a proxy server. You also need to set MaxClients correctly. Beyond that, writing code that doesn't suck goes a long way.

Re:general note: what is it

[ajs]

This is the common view of mod_perl, but it's also rather limited.

A more general view of mod_perl is that it's the Perl interface to the apache API. This means a lot of things to a lot of different kinds of developers, since the Apache API is so rich. It can be used for any of the following things:

• Writing one-shot programs that run "close to the server" (this is the primary, and rather limited use of mod_perl).
  
• Handling error conditions (e.g. file not found or failed execution)
  
• Writing your own page-generation caching system.
  
• Writing a content management system (e.g. bricolage)
  
• Redirecting requests. One example would be taking a request, examining the cookies, and redirecting based on "user".
  
• Proxying. You might, for example, like to proxy part of a request to one back-end and another part to another back-end with a minimum of overhead. That's easy with mod_perl and doesn't require as much work as you might think.
  
• SSL certificate integration with database of users.
  

You can go on and on with this. The bottom line is that mod_perl isn't really an application builder's toolkit, so much as it's the toolkit-builder's toolkit.

So many times, I've heard people try to compare mod_perl to full-fledged content management systems, and that's just not what mod_perl is. In fact, it's not even a templating system like PHP. It's just the Apache API mocked up into Perl. Granted, there's more than that. There are some utility features, but if you want templating, look at HTML::Mason. If you want content management, look at bricolage. These are systems build on top of mod_perl, and they will reduce (vastly) the number of wheels you need to re-invent.