Class: Protocol::WebSocket::Frame

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/protocol/websocket/frame.rb

Constant Summary collapse

CONTINUATION =

Opcodes

0x0
TEXT = 
0x1
BINARY = 
0x2
CLOSE = 
0x8
PING = 
0x9
PONG = 
0xA

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fin = true, opcode = 0, mask = nil, payload = nil) ⇒ Frame

Returns a new instance of Frame.

Parameters:

  • length (Integer) —

    the length of the payload, or nil if the header has not been read yet.



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# File 'lib/protocol/websocket/frame.rb', line 37

def initialize(fin = true, opcode = 0, mask = nil, payload = nil)
  @fin = fin
  @opcode = opcode
  @mask = mask
  @length = payload&.bytesize
  @payload = payload
end

Instance Attribute Details

#fin ⇒ Object

The generic frame header uses the following binary representation:

0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

-------------------------——————————-+ |F|R|R|R| opcode|M| Payload len | Extended payload length | |I|S|S|S| (4) |A| (7) | (16/64) | |N|V|V|V| |S| | (if payload len==126/127) | | |1|2|3| |K| | | ------------------------- - - - - - - - - - - - - - - - + | Extended payload length continued, if payload len == 127 | + - - - - - - - - - - - - - - - ------------------------------- | |Masking-key, if MASK set to 1 | -------------------------------——————————-+ | Masking-key (continued) | Payload Data | ——————————– - - - - - - - - - - - - - - - : Payload Data continued … : + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + | Payload Data continued … | ---------------------------------------------------------------



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# File 'lib/protocol/websocket/frame.rb', line 92

def fin
  @fin
end

#length ⇒ Object

Returns the value of attribute length.



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# File 'lib/protocol/websocket/frame.rb', line 95

def length
  @length
end

#mask ⇒ Object

Returns the value of attribute mask.



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# File 'lib/protocol/websocket/frame.rb', line 94

def mask
  @mask
end

#opcode ⇒ Object

Returns the value of attribute opcode.



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# File 'lib/protocol/websocket/frame.rb', line 93

def opcode
  @opcode
end

#payload ⇒ Object

Returns the value of attribute payload.



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# File 'lib/protocol/websocket/frame.rb', line 96

def payload
  @payload
end

Class Method Details

.read(stream) ⇒ Object 



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# File 'lib/protocol/websocket/frame.rb', line 45

def self.read(stream)
  frame = self.new
  
  if frame.read(stream)
    return frame
  end
rescue EOFError
  return nil
end

Instance Method Details

#<=>(other) ⇒ Object 



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# File 'lib/protocol/websocket/frame.rb', line 55

def <=> other
  to_ary <=> other.to_ary
end

#continued? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/protocol/websocket/frame.rb', line 67

def continued?
  @fin == false
end

#control? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/protocol/websocket/frame.rb', line 63

def control?
  @opcode & 0x8
end

#pack(payload) ⇒ Object 



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# File 'lib/protocol/websocket/frame.rb', line 102

def pack(payload)
  @payload = payload
  @length = payload.bytesize
  
  if @length.bit_length > 64
    raise ProtocolError, "Frame length #{@length} bigger than allowed 64-bit field!"
  end
end

#read(stream) ⇒ Object 



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# File 'lib/protocol/websocket/frame.rb', line 111

def read(stream)
  buffer = stream.read(2) or raise EOFError
  first, second = buffer.unpack("CC")
  
  @fin = (first & 0b1000_0000 != 0)
  # rsv = byte & 0b0111_0000
  @opcode = first & 0b0000_1111
  
  @mask = (second & 0b1000_0000 != 0)
  @length = second & 0b0111_1111
  
  if @length == 126
    buffer = stream.read(2) or raise EOFError
    @length = buffer.unpack('n').first
  elsif @length == 127
    buffer = stream.read(4) or raise EOFError
    @length = buffer.unpack('Q>').first
  end
  
  if @mask
    @mask = stream.read(4) or raise EOFError
    @payload = read_mask(@mask, @length, stream)
  else
    @mask = nil
    @payload = stream.read(@length) or raise EOFError
  end
  
  if @payload&.bytesize != @length
    raise ProtocolError, "Invalid payload size: #{@length} != #{@payload.bytesize}!"
  end
  
  return true
end

#to_ary ⇒ Object 



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# File 'lib/protocol/websocket/frame.rb', line 59

def to_ary
  [@fin, @opcode, @mask, @length, @payload]
end

#unpack ⇒ Object 



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# File 'lib/protocol/websocket/frame.rb', line 98

def unpack
  @payload
end

#write(stream) ⇒ Object 



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# File 'lib/protocol/websocket/frame.rb', line 145

def write(stream)
  buffer = String.new.b
  
  if @payload&.bytesize != @length
    raise ProtocolError, "Invalid payload size: #{@length} != #{@payload.bytesize}!"
  end
  
  if @mask and @mask.bytesize != 4
    raise ProtocolError, "Invalid mask length!"
  end
  
  if length <= 125
    short_length = length
  elsif length.bit_length <= 16
    short_length = 126
  else
    short_length = 127
  end
  
  buffer << [
    (@fin ? 0b1000_0000 : 0) | @opcode,
    (@mask ? 0b1000_0000 : 0) | short_length,
  ].pack('CC')
  
  if short_length == 126
    buffer << [@length].pack('n')
  elsif short_length == 127
    buffer << [@length].pack('Q>')
  end
  
  if @mask
    buffer << @mask
    write_mask(@mask, @payload, buffer)
    stream.write(buffer)
  else
    stream.write(buffer)
    stream.write(@payload)
  end
end