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|
# encoding: BINARY
module EventMachine
module WebSocket
module Framing07
def initialize_framing
@data = MaskedString.new
@application_data_buffer = '' # Used for MORE frames
@frame_type = nil
end
def process_data
error = false
while !error && @data.size >= 2
pointer = 0
fin = (@data.getbyte(pointer) & 0b10000000) == 0b10000000
# Ignoring rsv1-3 for now
opcode = @data.getbyte(pointer) & 0b00001111
pointer += 1
mask = (@data.getbyte(pointer) & 0b10000000) == 0b10000000
length = @data.getbyte(pointer) & 0b01111111
pointer += 1
# raise WebSocketError, 'Data from client must be masked' unless mask
payload_length = case length
when 127 # Length defined by 8 bytes
# Check buffer size
if @data.getbyte(pointer+8-1) == nil
debug [:buffer_incomplete, @data]
error = true
next
end
# Only using the last 4 bytes for now, till I work out how to
# unpack 8 bytes. I'm sure 4GB frames will do for now :)
l = @data.getbytes(pointer+4, 4).unpack('N').first
pointer += 8
l
when 126 # Length defined by 2 bytes
# Check buffer size
if @data.getbyte(pointer+2-1) == nil
debug [:buffer_incomplete, @data]
error = true
next
end
l = @data.getbytes(pointer, 2).unpack('n').first
pointer += 2
l
else
length
end
# Compute the expected frame length
frame_length = pointer + payload_length
frame_length += 4 if mask
if frame_length > @connection.max_frame_size
raise WSMessageTooBigError, "Frame length too long (#{frame_length} bytes)"
end
# Check buffer size
if @data.getbyte(frame_length - 1) == nil
debug [:buffer_incomplete, @data]
error = true
next
end
# Remove frame header
@data.slice!(0...pointer)
pointer = 0
# Read application data (unmasked if required)
@data.read_mask if mask
pointer += 4 if mask
application_data = @data.getbytes(pointer, payload_length)
pointer += payload_length
@data.unset_mask if mask
# Throw away data up to pointer
@data.slice!(0...pointer)
frame_type = opcode_to_type(opcode)
if frame_type == :continuation
if !@frame_type
raise WSProtocolError, 'Continuation frame not expected'
end
else # Not a continuation frame
if @frame_type && data_frame?(frame_type)
raise WSProtocolError, "Continuation frame expected"
end
end
# Validate that control frames are not fragmented
if !fin && !data_frame?(frame_type)
raise WSProtocolError, 'Control frames must not be fragmented'
end
if !fin
debug [:moreframe, frame_type, application_data]
@application_data_buffer << application_data
# The message type is passed in the first frame
@frame_type ||= frame_type
else
# Message is complete
if frame_type == :continuation
@application_data_buffer << application_data
message(@frame_type, '', @application_data_buffer)
@application_data_buffer = ''
@frame_type = nil
else
message(frame_type, '', application_data)
end
end
end # end while
end
def send_frame(frame_type, application_data)
debug [:sending_frame, frame_type, application_data]
if @state == :closing && data_frame?(frame_type)
raise WebSocketError, "Cannot send data frame since connection is closing"
end
frame = ''
opcode = type_to_opcode(frame_type)
byte1 = opcode | 0b10000000 # fin bit set, rsv1-3 are 0
frame << byte1
length = application_data.size
if length <= 125
byte2 = length # since rsv4 is 0
frame << byte2
elsif length < 65536 # write 2 byte length
frame << 126
frame << [length].pack('n')
else # write 8 byte length
frame << 127
frame << [length >> 32, length & 0xFFFFFFFF].pack("NN")
end
frame << application_data
@connection.send_data(frame)
end
def send_text_frame(data)
send_frame(:text, data)
end
private
FRAME_TYPES = {
:continuation => 0,
:text => 1,
:binary => 2,
:close => 8,
:ping => 9,
:pong => 10,
}
FRAME_TYPES_INVERSE = FRAME_TYPES.invert
# Frames are either data frames or control frames
DATA_FRAMES = [:text, :binary, :continuation]
def type_to_opcode(frame_type)
FRAME_TYPES[frame_type] || raise("Unknown frame type")
end
def opcode_to_type(opcode)
FRAME_TYPES_INVERSE[opcode] || raise(WSProtocolError, "Unknown opcode #{opcode}")
end
def data_frame?(type)
DATA_FRAMES.include?(type)
end
end
end
end
|
