lib/websocket/frame/data.rb
# frozen_string_literal: true
module WebSocket
module Frame
class Data < String
def initialize(*args)
super(*convert_args(args))
@masking_key = nil
end
def <<(*args)
super(*convert_args(args))
end
# Convert all arguments to ASCII-8BIT for easier traversing
def convert_args(args)
args.collect { |arg| arg.dup.force_encoding('ASCII-8BIT') }
end
# Extract mask from 4 first bytes according to spec
def set_mask
raise WebSocket::Error::Frame::MaskTooShort if bytesize < 4
@masking_key = self[0..3].bytes.to_a
end
# Remove mask flag - it will still be present in payload
def unset_mask
@masking_key = nil
end
# Extract `count` bytes starting from `start_index` and unmask it if needed.
def getbytes(start_index, count)
data = self[start_index, count]
data = mask(data.bytes.to_a, @masking_key).pack('C*') if @masking_key
data
end
# Mask whole payload using mask key
def mask(payload, mask)
return mask_native(payload, mask) if respond_to?(:mask_native)
result = []
payload.each_with_index do |byte, i|
result[i] = byte ^ mask[i % 4]
end
result
end
end
end
end