Until today we were happy users of Hpricot (0.8.1) . Easy to use, nice API, fast (enough)… but today we had to move a project over to Nokogiri.Why? Hpricot does not support XPath with namespaces. Worse: it does not even complain when you use a namespaced XPath query. It just keeps telling you that your XPath ended up in Nirvana and that there is no result.“Hey pal, you are using namespaces in XPath and i do not understand this” would have been a nice message.Since Hpricot does properly parse the namespaces, you can work around the problem using the at (aliased as %) method. But we need full XPath support hence the switch to Nokogiri.Some links i came across while researching the issue:

• http://enfranchisedmind.com/blog/posts/hpricot-does-namespaces
• http://www.rubyinside.com/nokogiri-ruby-html-parser-and-xml-parser-1288.html

Wan’t to know what language a text is written in? Maybe a comment on your Blog, an e-Mail you received, let your CMS guess the language of an article? Enter the babel gem!

Babel uses a n-gram approach to build reference profiles for languages. It also builds a profile for the input text and then calculates the distance between each reference profile and the input profile. The closest profile is probably the one with the language of the input text. Proabably. Chances are that Babel gives you wrong results on short sentences or single words.  You want to know more? Here is a paper that describes and compares different approaches.

We’ve setup a demo app so you can try out babel. And of course you can get the gem from github.

Thanks to the neat Inflector if ActiveSupport we know that the plural of tax is taxes. But if you ask for the singular form of taxes the inflector will try to convince you that it’s taxis!

>> "tax".pluralize.singularize
=>"taxis"

The reason we even found out about this was, that our tests (you do write tests, do you?) blew up when we used the taxes() fixture with a FixtureClassNotFound error. Of course: we do not have a Taxis class.

So how do you fix this? Simple: Edit config/inflections and add your own rule:

ActiveSupport::Inflector.inflections do |inflect|
  inflect.irregular 'tax', 'taxes'
end

>> "tax".pluralize.singularize
=> "tax"

Be sure to prefix Inflector with the ActiveSupport module. Otherwise you’ll face `load_missing_constant’:NameError: uninitialized constant Inflector

Railsworld now tells the world about new rails sites through twitter.

New additions are tweeted when they are ranked the first time. We do not tweet changes to the ranks as this would be a bit noisy. Follow @railsworld if you are interested.

Railsworld is our demo application. We use it to show customers how rails development works.We will add more tiny features from time to time…

We’ve written up a tiny ruby gem for the compete api. It can be used to query the compete service for ranking and trust information about a domain. We’ll eventually integrate it into railsworld.com so we have another source for ranking information (right now it’s alexa).

 Find more at the github repo for the compete gem

We are happy that we won Docuteam as a new customer. During the next months we will be implementing a proof of concept application using Ruby on Rails and ActiveFedora.

Lots of people seem to have troubles getting the MySQL gem installed on OS X. Here is what i use:

sudo gem install mysql -- --with-mysql-config=/opt/local/lib/mysql5/bin/mysql_config 

On my machine MySQL5 was installed using port then the path to the config should be correct. Otherwise either you know where the config file is (because you’ve installed MySQL yourself and you know what you are doing but then you would not need to read this) or you have to search for it. Try

which mysql_config 

and if this does not work try

find / -name mysql_config

(and go get a cup of coffee).

We’ve recently moved the Nicole’s site from a Rails version 1.youdontwannaknow to a Radiant based system. With some extensions (reorder, redirect and a custom permission system) the site was easy to develop and is now faster (thanks caching, i like you) and easier to manage. Kudos to the Radiant Team.

We’ve just added a small bugfix to the has_setting gem. Latest version is now 0.3.8.

has_setting is a dead simple ActiveRecord extension to store settings.

I just pushed a new version of the scriptaculous multi drag and drop addon. It’s much cleaner, supports mere Draggables and can react on shift clicks too. Check it out at http://simplificator.com/scriptaculous-multidrag/ (source is available on Github).