From: Jano Svitok <jan.svitok@...>
Date: 2008-05-14T06:18:06+09:00
Subject: Re: modify output of script

On Tue, May 13, 2008 at 10:28 PM, Kt Br wrote:
> I've got some LDAP data I'm trying to pipe into a ruby script.
>
>  Here is an example of the data there are multiple groups (dn) in the
>  real data set.  Sometimes the groups (dn) don't have a "seeAlso" or
>  "owner" associated with it:
>
>  dn: cn=test_group,ou=groups,dc=example,dc=com
>  owner: uid=jsmith,ou=people,dc=example,dc=com
>  seeAlso: uid=bwilliams,ou=people,dc=example,dc=com
>
>  Here is my script:
>
>  ----------------------------------------------------------

Try simple state machine - either you are processing first group (then
nothing is needed), or any other (prefix with newline),
and processing the first user/address/howyoucallit (do nothing) or
later (prefix with ',')

#!/usr/bin/ruby

unless STDIN.tty?
  first_group, first_user = true, true
  while((line = STDIN.gets))
    case line
    when /dn: cn=(.*),ou=groups,dc=example,dc=com/ # it's possible to
use regexps in case statements
      puts unless first_group
      print $1
      first_group, first_user = false, true
    when /(?:owner|seeAlso): uid=(.*),ou=people,dc=example,dc=com/  #
joined the two in one regexp, notice (?:) non-capturing group
      print ',' unless first_user
      print " #{$1}@example.com"
      first_user = false
    end
  end
  puts # final newline
end

Alternative approach would be to create a hash indexed by groups, and
values would be arrays of users.
i.e. info = Hash.new{ |h,k| h[k] = [] }
then when dn: group = $1
otherwise: info[group] << $1
When finished, just iterate over keys and values

puts info.map {|k,v| "#{k} #{v.join(', ')"}.join("\n")

Note that this approach will reorder the groups.