Introducing the Dynarex gem

The Dynarex gem makes it convenient to read Dynarex records as a hash.

Installation

sudo gem install dynarex

Successfully installed dynarex-0.1.0
1 gem installed
Installing ri documentation for dynarex-0.1.0...
Updating class cache with 2747 classes...
Installing RDoc documentation for dynarex-0.1.0...

Example

require 'dynarex'

url = 'http://www.jamesrobertson.eu/dynarex/scotruby2010-all.xml'
users = Dynarex.new(url).records

# display the top 5 twitter users with the most followers
users.sort_by {|x| -x[:followers_count].to_i}[0..4].each_with_index do |user, i|
  puts "%d %+4s %s" % [i+1, user[:followers_count], user[:twitter_name]]
end

output:

1 8947 timbray
2 2510 jimweirich
3 2228 marick
4 1837 chacon
5 1619 objo

Here's the code for the Dynarex class

class Dynarex
  include REXML 

  def initialize(location)
    open(location)
  end

  def summary
    @summary
  end

  def records
    @records
  end

  private

  def open(location)
    if location[/^https?:\/\//] then
      buffer = Kernel.open(location, 'UserAgent' => 'Dynarex-Reader').read
    else
      buffer = File.open(location,'r').read
    end
    @doc = Document.new buffer
    @summary = summary_to_h
    @records = records_to_h
  end

  def display()
    puts @doc.to_s
  end

  def records_to_h
    XPath.match(@doc.root, 'records/*').map do |row|
      XPath.match(row, '*').inject({}) do |r,node|
        r[node.name.to_s.to_sym] = node.text.to_s
        r
      end
    end
  end

  def summary_to_h
    XPath.match(@doc.root, 'summary/*').inject({}) do |r,node|
      r[node.name.to_s.to_sym] = node.text.to_s
      r
    end
  end

end

Resources

• Dynarex

update: 08-May-2010 @ 10:24pm

The latest Dynarex gem update means the above code runs as follows:

users.sort_by {|key,value| -value[:body][:followers_count].to_i}[0..4].each_with_index do |user, i|
  puts "%d %+4s %s" % ([i+1] + [:followers_count, :twitter_name].map {|x| user[1][:body][x]})
end

update: 09-May-2010 @ 9:59pm

The Dynarex gem now supports the method 'flat_record' to return a read-only snapshot of the dynarex records as a simple hash e.g.

users = Dynarex.new(url).flat_records

# display the top 5 twitter users with the most followers
users.sort_by {|x| -x[:followers_count].to_i}[0..4].each_with_index do |user, i|
  puts "%d %+4s %s" % [i+1, user[:followers_count], user[:twitter_name]]
end