@@ -33,7 +33,7 @@ First, lets get a simple array of our types: For each type, we’ll get a handle on the class with that name: -{% highlight ruby %}types.each { |type| model = Object.const_get(type){% endhighlight %} +{% highlight ruby %}types.each do |type| model = Object.const_get(type){% endhighlight %} We’ll execute our ActiveRecord statement @@ -41,15 +41,15 @@ We’ll execute our ActiveRecord statement Get an array of the “name” property -{% highlight ruby %}map = listing.map(&:name);{% endhighlight %} +{% highlight ruby %}names = listing.map(&:name);{% endhighlight %} Now, we’ll create those instance variables on the object, the first being a comma-separated listing of the names: -{% highlight ruby %}self.instance_variable_set("@" + type, map.join(", ")){% endhighlight %} +{% highlight ruby %}self.instance_variable_set("@" + type, names.join(", ")){% endhighlight %} The second being a count of the elements: -{% highlight ruby %}self.instance_variable_set("@" + type + "_count", map.length) }{% endhighlight %} +{% highlight ruby %}self.instance_variable_set("@" + type + "_count", names.length) }{% endhighlight %} We could get into why we need those two variables (one for the list and another for the count), but I think this is a nice example of how to use instance_variable_set anyway. Ruby. Dynamic. Awesome. @@ -57,12 +57,12 @@ The full snippet: {% highlight ruby %} types = ["Manufacturer", "Architecture", "Platform"] -types.each { |type| +types.each do |type| model = Object.const_get(type) listing = model.find(:all, :select =>"name") type = type.downcase - map = listing.map(&:name); - self.instance_variable_set("@" + type, map.join(", ")) - self.instance_variable_set("@" + type + "_count", map.length) -} + names = listing.map(&:name); + self.instance_variable_set("@" + type, names.join(", ")) + self.instance_variable_set("@" + type + "_count", names.length) +end {% endhighlight %} \ No newline at end of file _posts/2007-11-04-dancing-with-dynamic-features-in-ruby.textile @@ -71,3 +71,9 @@ Loading development environment (Rails 2.1.0) {% endhighlight %} Note: 30.minutes.from_now.time will result in a Time class, and will work equally as well as (Time.now + 30.minutes). It's up to you which of those two are more readable and intention revealing. + +h4. Caution: Feed parsing is hard + +The best part about feed standards is that there are so many to choose from! The code above is trivial, and will only handle feeds that fit that particular convention. Since I'm consuming feeds that I am also responsible for creating, I can opt for this _simplest thing that could possibly work_ approach. + +As soon as you start consuming several feeds, you'll start to see just how diverse these feeds can be. Empty channels, posts without titles, non-unique identifiers... these are just the beginning. I'd love to hear what robust feed parsers folks are using in Ruby. The best feed parser I know of, and that some Rubists even use, is "Universal Feed Parser":http://www.feedparser.org/, a Python library with 3k unit tests. Good luck! \ No newline at end of file _posts/2008-11-28-quick-and-easy-cache-rss-feeds-rails.textile _posts/2008-04-05-using-ajax-to-load-rails-partials.textile cd2cdb44e82f76c938a39db94cf022a53e3106d6 Brian Doll brian@emphaticsolutions.com http://github.com/briandoll/emphaticsolutions.com/commit/a7a4bb0c7432bee00b62c501267df8514c69b492 a7a4bb0c7432bee00b62c501267df8514c69b492 2009-05-11T08:52:15-07:00 2009-05-11T08:52:15-07:00 some post cleanup ef2f895f2b6c4d0b3249cdbd7676c16707240403 Brian Doll brian@emphaticsolutions.com