Class: RABX::Message

Inherits:
Object
  • Object
show all
Defined in:
lib/rabx/message.rb,
lib/rabx/message/version.rb

Direct Known Subclasses

ErrorMessage, RequestMessage, SuccessMessage

Defined Under Namespace

Classes: Error, InterfaceError, ProtocolError

Constant Summary collapse

VERSION = 
"0.0.1"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(s) ⇒ Message

Returns a new instance of Message.

Parameters:

  • s (String) —

    a RABX message



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# File 'lib/rabx/message.rb', line 49

def initialize(s)
  if s.empty?
    raise ProtocolError, 'string is too short'
  end
  @s = s.dup # string
  @p = 1 # pointer
  @size = @s.size
  @version = getnetstring
  parse
end

Instance Attribute Details

#version ⇒ Object (readonly)

Returns the value of attribute version.



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# File 'lib/rabx/message.rb', line 46

def version
  @version
end

Class Method Details

.dump(type, *args) ⇒ String

Dumps a RABX message.

Parameters:

  • type (String) —

    a message type

  • args (Array) —

    message contents

Returns:

  • (String) —

    the REBX message



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# File 'lib/rabx/message.rb', line 14

def self.dump(type, *args)
  string = type + Netstring.dump('0')
  if type == 'R'
    string + Netstring.dump(args[0]) + _dump(args[1])
  elsif type == 'S'
    if args.size.zero?
      string
    else
      string + _dump(args[0])
    end
  elsif type == 'E'
    string + Netstring.dump(args[0].to_s) + Netstring.dump(args[1]) + _dump(args[2])
  end
end

.load(s) ⇒ Message

Loads a RABX message.

Parameters:

  • s (String) —

    a RABX message

Returns:



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# File 'lib/rabx/message.rb', line 33

def self.load(s)
  case s[0]
  when 'R'
    RequestMessage.new(s)
  when 'S'
    SuccessMessage.new(s)
  when 'E'
    ErrorMessage.new(s)
  else
    raise ProtocolError, %(unknown RABX message type "#{s[0]}")
  end
end

Instance Method Details

#eof? ⇒ Boolean

Returns whether the reader has reached the end-of-file.

Returns:

  • (Boolean) —

    whether the reader has reached the end-of-file



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# File 'lib/rabx/message.rb', line 77

def eof?
  @p == @size
end

#getnetstring ⇒ Netstring?

Loads a netstring from the current position in the message.

Returns:

  • (Netstring, nil) —

    a string, or nil if at end-of-file



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# File 'lib/rabx/message.rb', line 84

def getnetstring
  if eof?
    nil
  else
    string = Netstring.load(@s[@p..-1])
    @p += string.netstring.size
    string
  end
rescue Netstring::Error => e
  raise ProtocolError, "#{e.message} in netstring starting at #{@p}"
end

#gets ⇒ Object

Loads a typed netstring from the current position in the message.

Returns:

  • the contents of the netstring, or nil if at end-of-file



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# File 'lib/rabx/message.rb', line 99

def gets
  if eof?
    nil
  else
    type = @s[@p]
    @p += 1

    if type == 'N' # null
      return nil
    end

    case type
    when 'I' # integer
      value = getnetstring.to_s
      begin
        Integer(value)
      rescue ArgumentError
        raise ProtocolError, %(expected integer, got #{value.inspect} at position #{@p - value.size - 1})
      end
    when 'R' # real
      value = getnetstring.to_s
      begin
        Float(value)
      rescue ArgumentError
        raise ProtocolError, %(expected float, got #{value.inspect} at position #{@p - value.size - 1})
      end
    when 'T', 'B' # text, binary
      getnetstring
    when 'L' # list
      value = getnetstring.to_s
      begin
        size = Integer(value)
      rescue ArgumentError
        raise ProtocolError, %(expected integer, got #{value.inspect} at position #{@p - value.size - 1})
      end
      array = []
      size.times do |n|
        if eof?
          raise ProtocolError, %(expected #{size} items, got #{n} items at position #{@p})
        end
        array << gets
      end
      array
    when 'A' # associative array
      value = getnetstring.to_s
      begin
        size = Integer(value)
      rescue ArgumentError
        raise ProtocolError, %(expected integer, got #{value.inspect} at position #{@p - value.size - 1})
      end
      hash = {}
      size.times do |n|
        if eof?
          raise ProtocolError, %(expected #{size} items, got #{n} items at position #{@p})
        end
        key = gets # test for repeated keys?
        if eof?
          raise ProtocolError, %(expected value, got end-of-file at position #{@p})
        end
        hash[key] = gets
      end
      hash
    else
      raise ProtocolError, %(bad type character "#{type}" at position #{@p})
    end
  end
end

#to_s ⇒ String

Returns the RABX message.

Returns:

  • (String) —

    the RABX message



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# File 'lib/rabx/message.rb', line 63

def to_s
  @s
end

#type ⇒ String

Returns the message type.

Returns:

  • (String) —

    the message type



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# File 'lib/rabx/message.rb', line 70

def type
  @s[0]
end