RPSL/lib/rpsl.rb

# Library which provides functions for reading and writing Routing Policy Specification Language (RPSL, RFC2622).
module RPSL
  # Generic error when processing RPSL
  class RPSLError < StandardError; end

  # Error while loading RPSL
  class ParserError < RPSLError; end

  # Error while generating RPSL
  class DumpError < RPSLError; end

  # Parses a string as RPSL.
  # @param rpsl [String] The RPSL data as an object which can be iterated
  #   with each_line.
  # @return [Hash] Hash containing the RPSL data.
  # @example
  #   rpsl = <<EOF
  #   route6:             fd42:4242:2601:ffff::/64
  #   descr:              This is an ROA test object
  #   max-length:         112
  #   remarks:
  #                       This object is designed to test ROA scripts
  #                       in a number of ways.
  #   +
  #                       The expected output for this route should be:
  #                       roa fd42:4242:2601:ffff::/64 max 64 as 0;
  #   +
  #                       This is not a blank line
  #                       + ----- +
  #   +
  #                       The first test is to include a number of syntax
  #                       corner cases, designed to trip up parsers
  #   +
  #                       The first max-length line should be clamped
  #                       to the maximums defined in filter6.txt
  #   +
  #                       The second max-length is part of the remark
  #                       and should be ignored.
  #   +
  #                       max-length: 48
  #   +
  #   origin:             AS0
  #   mnt-by:             BURBLE-MNT
  #   source:             DN42
  #   EOF
  #
  #   RPSL.load(rpsl) # => {"route6"=>"fd42:4242:2601:ffff::/64\n",
  #                   #     "descr"=>"This is an ROA test object\n",
  #                   #     "max-length"=>"112\n",
  #                   #     "remarks"=>
  #                   #      "\n" +
  #                   #      "This object is designed to test ROA scripts\n" +
  #                   #      "in a number of ways.\n" +
  #                   #      "\n" +
  #                   #      "The expected output for this route should be:\n" +
  #                   #      "roa fd42:4242:2601:ffff::/64 max 64 as 0;\n" +
  #                   #      "\n" +
  #                   #      "This is not a blank line\n" +
  #                   #      "+ ----- +\n" +
  #                   #      "\n" +
  #                   #      "The first test is to include a number of syntax\n" +
  #                   #      "corner cases, designed to trip up parsers\n" +
  #                   #      "\n" +
  #                   #      "The first max-length line should be clamped\n" +
  #                   #      "to the maximums defined in filter6.txt\n" +
  #                   #      "\n" +
  #                   #      "The second max-length is part of the remark\n" +
  #                   #      "and should be ignored.\n" +
  #                   #      "\n" +
  #                   #      "max-length: 48\n" +
  #                   #      "\n",
  #                   #     "origin"=>"AS0\n",
  #                   #     "mnt-by"=>"BURBLE-MNT\n",
  #                   #     "source"=>"DN42\n"}
  def self.load(rpsl)
    obj = {}
    current_section = nil

    rpsl.to_s.each_line.with_index do |line, lineno|
      line.chomp!

      case line
      when /^([\d\w\-_]+): *(.*)$/
        current_section = $1

        obj[current_section] = "#{obj[current_section]}#{$2}\n"
      when /^[+ \s] *(.+)$/
        raise ParserError, "Value without key in line #{lineno + 1}" unless current_section

        obj[current_section] = "#{obj[current_section]}#{$1}\n"
      when /^\+ *$/
        raise ParserError, "Empty line without key in line #{lineno + 1}" unless current_section

        obj[current_section] = "#{obj[current_section]}\n"
      else
        raise ParserError, "Failed to parse line #{lineno + 1}."
      end
    end

    return obj
  end

  # Converts a hash into the RPSL format.
  # @param obj [Hash] Hash in which the data to be converted is stored.
  # @param value_column [Integer, NilClass] `nil` or the column where the
  #   value should start.
  # @example
  #   obj = {"route6"=>"fd42:4242:2601:ffff::/64",
  #          "descr"=>"This is an ROA test object",
  #          "max-length"=>"112",
  #          "remarks"=>
  #          "\n" +
  #          "This object is designed to test ROA scripts\n" +
  #          "in a number of ways.\n" +
  #          "\n" +
  #          "The expected output for this route should be:\n" +
  #          "roa fd42:4242:2601:ffff::/64 max 64 as 0;\n" +
  #          "\n" +
  #          "This is not a blank line\n" +
  #          "+ ----- +\n" +
  #          "\n" +
  #          "The first test is to include a number of syntax\n" +
  #          "corner cases, designed to trip up parsers\n" +
  #          "\n" +
  #          "The first max-length line should be clamped\n" +
  #          "to the maximums defined in filter6.txt\n" +
  #          "\n" +
  #          "The second max-length is part of the remark\n" +
  #          "and should be ignored.\n" +
  #          "\n" +
  #          "max-length: 48",
  #          "origin"=>"AS0",
  #          "mnt-by"=>"BURBLE-MNT",
  #          "source"=>"DN42"}
  #
  #   RPSL.dump(obj, 20) # => "route6:             fd42:4242:2601:ffff::/64\n" +
  #                      #    "descr:              This is an ROA test object\n" +
  #                      #    "max-length:         112\n" +
  #                      #    "remarks:            \n" +
  #                      #    "                    This object is designed to test ROA scripts\n" +
  #                      #    "                    in a number of ways.\n" +
  #                      #    "+\n" +
  #                      #    "                    The expected output for this route should be:\n" +
  #                      #    "                    roa fd42:4242:2601:ffff::/64 max 64 as 0;\n" +
  #                      #    "+\n" +
  #                      #    "                    This is not a blank line\n" +
  #                      #    "                    + ----- +\n" +
  #                      #    "+\n" +
  #                      #    "                    The first test is to include a number of syntax\n" +
  #                      #    "                    corner cases, designed to trip up parsers\n" +
  #                      #    "+\n" +
  #                      #    "                    The first max-length line should be clamped\n" +
  #                      #    "                    to the maximums defined in filter6.txt\n" +
  #                      #    "+\n" +
  #                      #    "                    The second max-length is part of the remark\n" +
  #                      #    "                    and should be ignored.\n" +
  #                      #    "+\n" +
  #                      #    "                    max-length: 48\n" +
  #                      #    "origin:             AS0\n" +
  #                      #    "mnt-by:             BURBLE-MNT\n" +
  #                      #    "source:             DN42\n"
  def self.dump(obj, value_column = nil)
    rpsl = ''

    obj.each do |key, value|
      lines = value.to_s.lines
      lines.map!(&:chomp)
      first_value = lines.shift

      key = key.to_s

      if value_column
        padding_length = value_column.to_i - 1 - key.length
        raise DumpError, 'Key too long.' if padding_length.negative?

        padding = ' ' * padding_length
      end

      rpsl += "#{key}:#{padding}#{first_value}\n"
      lines.each do |line|
        rpsl += if line.empty?
                  "+\n"
                elsif value_column
                  "#{' ' * value_column}#{line}\n"
                else
                  " #{line}\n"
                end
      end
    end

    return rpsl
  end
end