Script extracting group information from a text file

get-groups.rb

#!/usr/bin/ruby -w

Group = Struct.new :name, :primary, :secondary, :editors

GET_UID = /uid=([^,]*)/

EXTRACT = {
  "dn" =>           [:name, /cn=([^,]*)/],
  "owner" =>        [:primary, GET_UID],
  "seeAlso" =>      [:secondary, GET_UID],
  "uniquemember" => [lambda {|group, ed| (group.editors ||= []) << ed}, GET_UID],
}

groups = []
def groups.update(group)
  self << group if group
  nil
end

current = nil

ARGF.each_line do |line|
  if /^\s*$/ =~ line
    # empty line
    current = groups.update(current)
  else
    instructions = EXTRACT[line[/^\w+/]]

    if instructions
      where, rx = *instructions
      data = line[rx, 1]
      current ||= Group.new

      if Proc === where
        where[current, data]
      else
        current[where] = data
      end
    end
  end
end

current = groups.update(current)

groups.sort_by!(&:name)

# debug:
# require 'pp'
# pp groups

# proper output:
groups.each do |group|
  puts "Group: #{group.name}",
        "Primary: #{group.primary}",
        "Secondary: #{group.secondary}"
  group.editors.sort.each {|ed| puts "Editor: #{ed}"}
  puts
end

test_groups.txt

dn: cn=group2,ou=groups,dc=example,dc=com
owner: uid=user1,ou=people,dc=example,dc=com
seeAlso: uid=user2,ou=people,dc=example,dc=com
uniquemember: uid=user1,ou=people,dc=example,dc=com
uniquemember: uid=user2,ou=people,dc=example,dc=com

dn: cn=group1,ou=groups,dc=example,dc=com
owner: uid=user8,ou=people,dc=example,dc=com
seeAlso: uid=user6,ou=people,dc=example,dc=com
uniquemember: uid=user8,ou=people,dc=example,dc=com
uniquemember: uid=user11,ou=people,dc=example,dc=com
uniquemember: uid=user20,ou=people,dc=example,dc=com