class DNSSD::TextRecord

DNSSD::TextRecord is a Hash delegate that can encode its contents for DNSSD.

Public Class Methods

new(text_record = nil) click to toggle source

Creates a new TextRecord decoding an encoded text_record if given or from a given Hash.

DNSSD::TextRecord.new "\003k=v"

DNSSD::TextRecord.new 'k' => 'v'

Calls superclass method

# File lib/dnssd/text_record.rb, line 18
def initialize(text_record = nil)
  super case text_record
        when Hash then
          text_record.dup
        when String then
          decode(text_record.dup)
        else
          Hash.new
        end
end

Public Instance Methods

decode(text_record) click to toggle source

Decodes text_record and returns a Hash

# File lib/dnssd/text_record.rb, line 32
def decode(text_record)
  record = {}

  tr = text_record.unpack 'C*'

  until tr.empty? do
    size  = tr.shift

    next if size.zero?

    raise ArgumentError, 'ran out of data in text record' if tr.length < size

    entry = tr.shift(size).pack('C*')

    raise ArgumentError, 'key not found' unless entry =~ /^[^=]/

    key, value = entry.split '=', 2

    next unless key

    record[key] = value
  end

  record
end

encode() click to toggle source

Encodes this TextRecord. A key value pair must be less than 255 bytes in length. Keys longer than 14 bytes may not be compatible with all clients.

# File lib/dnssd/text_record.rb, line 63
def encode
  sort.map do |key, value|
    key = key.to_s

    raise DNSSD::Error, "empty key" if key.empty?
    raise DNSSD::Error, "key '#{key}' contains =" if key =~ /=/

    record = value ? [key, value.to_s].join('=') : key

    raise DNSSD::Error, "key value pair at '#{key}' too large to encode" if
      record.length > 255

    "#{record.length.chr}#{record}"
  end.join ''
end