querying properties in many computers using session relevance

main.rb

#!/usr/bin/env ruby

#
# Based on https://www.ibm.com/developerworks/community/blogs/e9d21113-aa93-467e-ac77-a0d20a21eaec/entry/Session_Relevance_Computer_Properties_query_Efficiency?lang=en
#

class App
  def initialize
    @properties = []
    @template = File
      .open("template.rel")
      .readlines
      .select {|line| !line.strip.start_with?('#')}
      .join
  end

  def add_properties(properties)
    @properties += properties
  end

  def set_bes_computers_criteria(crit)
    @crit = crit
  end

  def generate_bes_properties_rel
    (@properties.map do |prop|
      "(bes property \"#{prop}\")"
    end).join ','
  end

  def generate_pass_properties_rel
    ([*1..@properties.count].map {|n| "item #{n} of it"}).join ','
  end

  def generate_display_properties_rel
    (@properties.each_with_index.map do |prop, index|
      index += 1
      "(concatenation \";\" of values of results (item 0 of it, item #{index} of it))"
    end).join ",\n"
  end

  def generate_query
    retval = @template
    [
      [/<bes computers>/, "set of (#{@crit})"],
      [/<bes properties>/, generate_bes_properties_rel],
      [/<pass properties>/, "#{generate_pass_properties_rel}"],
      [/<display properties>/, "#{generate_display_properties_rel}"],
      [/\n/, ""]
    ].each do |matching_regex, replacement|
      retval.gsub!(matching_regex, replacement)
    end
    puts retval
  end
end

app = App.new
app.add_properties([
  "Computer Name",
  "DOE Number",
  "Computer Serial Number",
  "IP Addresses",
  "Mac Addresses",
  "Last Report Time"
])
app.set_bes_computers_criteria('(unique values of applicable computers of bes fixlets whose ((cve id list of it) contains "CVE-2019-0708"))')
puts app.generate_query

result.rel

((concatenation ";" of values of results (item 0 of it, item 1 of it)),(concatenation ";" of values of results (item 0 of it, item 2 of it)),(concatenation ";" of values of results (item 0 of it, item 3 of it)),(concatenation ";" of values of results (item 0 of it, item 4 of it)),(concatenation ";" of values of results (item 0 of it, item 5 of it)),(concatenation ";" of values of results (item 0 of it, item 6 of it))) of (elements of item 0 of it /*expand the computer set - gets you one line per computer*/, item 1 of it,item 2 of it,item 3 of it,item 4 of it,item 5 of it,item 6 of it) of (set of ((unique values of applicable computers of bes fixlets whose ((cve id list of it) contains "CVE-2019-0708"))), (bes property "Computer Name"),(bes property "DOE Number"),(bes property "Computer Serial Number"),(bes property "IP Addresses"),(bes property "Mac Addresses"),(bes property "Last Report Time"))

template.rel

(
<display properties>
) of (
elements of item 0 of it /*expand the computer set - gets you one line per computer*/
, <pass properties>
) of (
<bes computers>
, <bes properties>
)