Customer Reviews

The Apache Modules Book: Application Development with Apache

5 star:		(6)
4 star:		(2)
3 star:		(0)
2 star:		(0)
1 star:		(1)

 

 

This book easily earns five stars despite a few glaring issues. Why? It's the best, most consitent, and approachable guide you'll find to writing Apache modules.

I spent two weeks scouring the net for APR examples and explanations. I started with the O'Reilly books only to find they are incredibly out of date. I moved on to Apache sanctioned module source code. I dissected source code for other modules only to find that the examples fluctuated on approach and, apparently, on the author's grasp of the entire APR libraries. Some folks wrote against previous APR version libraries and macros. Others used the updated APR. Still others rolled their own versions of functions that were already written, just not discovered. Tutorials varied in reliability with similar issues. And my desk quickly filled with highlighted and sticky-noted annotated examples.

This book replaced all those loose inconsistent notes with a solid example-centric nicely bound guide. Five stars. Just for that.

This book is not without problems though. First, it makes reference to programming paradigms which, frankly, I've never heard of before and which this book inadequately explains. Brigade buckets is an example. Bridage buckets are incrementally explained as a ring data store (eh?), a doubly linked list (okay, firm ground), and then a mechanism for passing data through layered IO (another eh?). I couldn't get much from the explanation. Googling "brigade bucket" led to IEEE DSP circuit design and a heated debate on using solid state delay effects for guitar pedals. Apparently brigade buckets don't quote share the same prolific status as, say, something more Knuth-ess.

The book explained thread safety in a similarly gap toothed summary. It offers this fatherly advice: avoid shared memory and make sure functions are reentrant. That wasn't much help for me. I'd prefer to have a detailed explanation of why the APR libraries have both reentrant and non-reentrant versions of the same functions. Wouldn't any reasonable programmer always use the reentrant version? If not, I'd like to know why... with some precision.

The final gripe: the book includes RFC 2616 in it's entirety. This needlessly adds 200 pages of non-original and otherwise easily (and FREEly) accessibe volume. Granted, the publisher formatted the RFC nicely. It's a bit easier to read than the fixed format of the real RFC. But why not add a few notes? The author could have taken the edge off of the RFC-legalese and made it a bit more approachable (think learning bible with more notes than text). At the risk of discouraging future books of this level, the RFC is a blatant copout and just a really disgusting way of bumping page numbers.

So, those are the issues I had. I'm still giving this a solid five as it outshines any other information I've found to date.

I tried to write an Apache module using only the documentation and reference material available on the net, and failed. The documentation you can find on the net (even on Apache.org's own website) is either completely out of date or maddeningly vague. If you spend enough time in trial and error you might get your module to work. Then again, you might not.

If you're trying to write or maintain an Apache module, this book is an invaluable tutorial and resource. It saved me a great deal of time and frustration.

I was (pleasantly) surprised by this.

I drive my website with Perl cgi scripts - basically a home grown CMS that gives me the control I want. I'd never thought much about the inner workings of the modules I do use, and certainly never thought that I could replace a tremendous amount of my cgi Perl code with a direct module. But after reading this, I realized it wouldn't be all that hard to do.

Now it is true that I haven't done much with C for a long, long time. In spite of that, I feel reasonably confident that I could extend the examples given in Nick's book to do exactly what I need much more quickly and efficiently - sure, there are higher level tasks that might be more than I could tackle, but the basics seem quite easy and attainable.

Well written, easy to follow (and downloadable) examples, and at least as far as I can tell, quite comprehensive. Good job!

This book came recommended to me from a well-learned Apache module developer, and I can't laud it enough. It is simply impossible to find another reference text out there that covers this topic with this level of completeness. I'm not really sure why the HTTP RFC and the Apache Software License is tacked on to the end of the book, but the real content of the book make it well worth the relatively hefty price tag.

Apache is more than a popular Web server; it's a versatile and complex platform covered well in THE APACHE MODULES BOOK, the first guide for developers who already work with Apache and want to make the most of its features. From code security and basic processing to C-based shortcuts and techniques, APACHE MODULES BOOK uses real-world code examples and techniques to provide an excellent manual of basics. Perfect for any serious programmer's Apache reference collection.

This should be considered a required resource if you need to learn about writing apache modules. It is the best introduction available to writing modules for Apache 2, and holds up well as a reference.

With all the buzz in recent years about various scripting languages like PHP or Perl, it is refreshing to see a book that takes an unabashed advocacy of plain old C. This is a solidly C programming book, showing how you can change a module or, more ambitiously, add a new module to Apache. It shows the conceptual framework of Apache; deliberately designed to permit third party extensions.

The text also describes an important practical case, where you are making a module, but want to link to a pre-existing library. In essence, your module extends both Apache and that library. Then there are the usual complications, like several modules linking to different versions of a library. Kew suggests avoiding linking in libraries, because of reasons like this. But he allows that other opinions exist.

Some programmers should look at the sections on filter chains. A very useful way to understand and arrange analysis. Decomposing an intricate analysis into different filtering stages can be useful in terms of writing and debugging the code. Apache is well suited to let you take this approach.

Of course, those of you programming in C should be well aware that this runs into scaling limits as the source code lengthens. Which is one of the reasons that many C programmers moved to C++ or Java. But so long as your modules are under 100 000 lines [roughly], then using C should be fine.

Well written with enough good examples to get you started. Nick is a current apache contributor and really understands the architecture. The section on debugging is invaluable. I buy one for each engineer who I have work on custom modules. Apache has an amazing and well thought out architecture, but is is different from other "c" language products that you might be used to, so expect to spend a few days getting your head around it. This book makes getting started much easier.

I have no idea why this book got consistantly high ratings. I can only surmise that the people who have used this book are already Apache geeks.

I have a lot of development experience in server development, and have developed in IIS among many other things. I've only used Apache to serve static pages and I wanted to develop an Apache module to replace my use of the IIS ISAPI (i.e. building a DLL). No matter how sophisticated or smart you are, when starting on a new project you need basic direction on how to get started, ESPECIALLY with the development environment. We're all familiar with the "Hello World" concept. Let me give you my "Hello World" experience with this lousy book:

It starts off encouraging as it give some broad concepts of Apache.

But it rapidly degrades into massive amounts of information with no conceptual framework on how all these things fit together. The first 4 chapters read largely like a reference book (i.e. you see lots of information that might be useful in the future, but you're totally confused). But it's not as good as a reference book because it's not indexed that way.

Finally in Chapter 5 it gets to the Hello World applicaiton. Again, extremely confusing, but at least there is a source code example. I thought to myself, "OK, finally I'm going to see if I can something basic working by just typing in the code". I'm working on Windows in Developer Studio. So I went to [...] and downloaded the binaries and the source. The book, said NOTHING about how to download Apache and what components you need, but I figure, OK, well apache is widely used, so this should be pretty straight forward...... NOT if you're developing modules!!!

I typed in the code example, and immediatley I couldn't figure out how to compile it as I was missing headers. I installed the apache source components, and found headers, but not all of them!. Then I saw, OK, I have to use a tool called "apxs" which is clearly indicated in the book. OK, I thought I'll try that instead of first trying to compile it in my development environment. Guess what? "apxs" is not installed with Apache!!!! I thought, "OK this is frustrating, OK, well it can't be difficult to find". Well after several hours I some some win32 version that had to be installed with perl. OK, so I downloaded Active Perl, and ran that scripts. Well that failed, because it toldPme I needed "libhttpd". What the heck is that? I'm smart, but I can't read the minds of the Apache developers and the author of the book. I started looking around for the apache-dev module which appears to contain "apxs", but that is nowhere to be found. I found something in Debian but that was a rat hole of confusion and wasted time. Well needless to say after googling around for 2 DAYS! I found no solution! Can you imagine how aggravating that is.

So I'm going to return this %^&^#%%# book

And I still don't understand how development works. This lousy author provided no conceptual framework! Can you use your own compiler (e.g. Dev Studio)? How do you test, how do you debug. I have to build an interface to MySQL, and I want to debug that in my environment first then debug while the server is running. a There appears to be some information at the end of the book, but I quite frankly have no desire to continue wasting my time with this crappy book!