def from_file(cls, fp):
"""
read a websockets frame header
"""
first_byte = utils.bytes_to_int(fp.safe_read(1))
second_byte = utils.bytes_to_int(fp.safe_read(1))
fin = utils.getbit(first_byte, 7)
rsv1 = utils.getbit(first_byte, 6)
rsv2 = utils.getbit(first_byte, 5)
rsv3 = utils.getbit(first_byte, 4)
# grab right-most 4 bits
opcode = first_byte & 15
mask_bit = utils.getbit(second_byte, 7)
# grab the next 7 bits
length_code = second_byte & 127
# payload_lengthy > 125 indicates you need to read more bytes
# to get the actual payload length
if length_code <= 125:
payload_length = length_code
elif length_code == 126:
payload_length = utils.bytes_to_int(fp.safe_read(2))
elif length_code == 127:
payload_length = utils.bytes_to_int(fp.safe_read(8))
# masking key only present if mask bit set
if mask_bit == 1:
masking_key = fp.safe_read(4)
else:
masking_key = None
return cls(
fin=fin,
rsv1=rsv1,
rsv2=rsv2,
rsv3=rsv3,
opcode=opcode,
mask=mask_bit,
length_code=length_code,
payload_length=payload_length,
masking_key=masking_key,
)
def __init__(self, key):
self.key = key
self.masks = [utils.bytes_to_int(byte) for byte in key]
self.offset = 0
def __init__(self, key):
self.key = key
self.masks = [utils.bytes_to_int(byte) for byte in key]
self.offset = 0
