Once again it has become time to refresh the site design. Looking back, it appears the last site refresh was in July of 2007—I’m not sure if 5 years on the same design demonstrates longevity and consistency, or if it just means I’m horribly overdue.
Regardless, now everything is nice and shiny. One of the goals of the new design was to do my best to leverage HTML5 and CSS3, including new HTML5 tags and use of many of the newer CSS features. As a consequence, the only image file is the background. Everything else is CSS effects along with a couple CSS fonts.
I also used the refresh as an excuse to experiment with responsive design. I haven’t had a chance to test a wide array of small-screen devices yet, but on the ones I have access to (various iDevices), the site is usable. I’d love to hear your experience, good or bad, on any kind of smaller-screen device.
Other changes include numerous updates to the software stack (Rails 3.2, etc.), better syntax highlighting (now with line numbers!), and improved (in theory) spam filtering.
It’s clearly time that I catch up with the world around me. It’s curious how much can pass you by while you’re consumed with other priorities. Now that some of those have passed, I’m rediscovering several things that got pushed aside.
Among them is hopefully writing at least a little more often here. Apparently, that won’t be a difficult bar to jump over—it’s been 2 1/2 years since my last post. Ack!
Apart from writing here, the process of catching up looks like it will include a bunch of software upgrades (Rails 3 a part of that), a new design for here, and migrating a bunch of stuff to git.
This is part 5 of my ongoing series on Ruby on Rails performance. Today’s topic is a bit more complicated that some of the previous parts.
I’m going to explore an alternative to using the method 1ActiveRecord::Base.to_xml.
Before I get into that, I probably should explain why. After all, 1ActiveRecord::Base.to_xml is really easy to use. The alternative I’m going to demonstrate isn’t very easy to use.
The problem is that 1ActiveRecord::Base.to_xml can be really slow—even after making the optimizations I’ve explored in the previous parts to this series. For fairly simple AR objects, this won’t be a problem. However, when you have a deep object hierarchy and need substantial portions of it to be included in the XML response, it becomes a problem.
One instance where I encountered this was a nested has_many tree. That is, the object tree looks something like this:
ParentObject has_many ChildObjects
Each ChildObject has_many OtherObjects
The XML output is often 100k or more, and representing a few dozen or more total objects.
In part 3 of my Ruby on Rails Performance Series we’ll look at how to improve the parsing speed of XML content.
Rails will automatically parse XML in two key places:
1. When XML content is sent to a controller/action pair via POST or PUT. (Your app is an API server.)
2. When XML content is received from an ActiveResource request. (Your app is an API client.)
The default XML parser is REXML. It’s written in pure Ruby which makes it very portable. And slow. Very slow.
So, we need to replace REXML with something faster. The key is the 1libxml-ruby gem which is just a binding to the very fast libxml2 C library.
libxml-ruby has a different set of methods from REXML and is not drop in compatible. If you’re planning on moving your own REXML parsing code to libxml-ruby, it will take some work. However, it’s worth it. In one particular project, I had about a 100x speed improvement!
Rails, as it often does, makes the switch to libxml-ruby super easy. First, install the gem (requires a functioning compiler, the libxml2 library, and headers for libxml2):
1gem install libxml-ruby
Then, just add a new file to 1config/initializers/. Let’s call it 1config/initializers/xml_config.rb. In that file, put this:
1ActiveSupport::XmlMini.backend = 'LibXML'
This was only added in recent versions of Rails, I believe in 2.3.