def receive(self):
if self._closed:
raise WebSocketError("Connection is already closed")
try:
return uwsgi.websocket_recv_nb()
except IOError, e:
self.close()
raise WebSocketError(e)
def send_frame(self, message, opcode):
"""
Send a frame over the websocket with message as its payload
"""
if self._closed:
raise WebSocketError("Connection is already closed")
if opcode == self.OPCODE_TEXT:
message = self._encode_bytes(message)
elif opcode == self.OPCODE_BINARY:
message = str(message)
header = Header.encode_header(True, opcode, '', len(message), 0)
try:
self.stream.write(header + message)
except socket_error:
raise WebSocketError("Socket is dead")
def read_frame(self):
"""
Block until a full frame has been read from the socket.
This is an internal method as calling this will not cleanup correctly
if an exception is called. Use `receive` instead.
:return: The header and payload as a tuple.
"""
header = Header.decode_header(self.stream)
if header.flags:
raise WebSocketError
if not header.length:
return header, ''
try:
payload = self.stream.read(header.length)
except socket_error:
payload = ''
except Exception:
# TODO log out this exception
payload = ''
if len(payload) != header.length:
raise WebSocketError('Unexpected EOF reading frame payload')
if header.mask:
payload = header.unmask_payload(payload)
return header, payload
def get_file_descriptor(self):
"""Return the file descriptor for the given websocket"""
try:
return uwsgi.connection_fd()
except IOError, e:
self.close()
raise WebSocketError(e)
def read_message(self):
"""
Return the next text or binary message from the socket.
This is an internal method as calling this will not cleanup correctly
if an exception is called. Use `receive` instead.
"""
opcode = None
message = ""
while True:
header, payload = self.read_frame()
f_opcode = header.opcode
if f_opcode in (self.OPCODE_TEXT, self.OPCODE_BINARY):
# a new frame
if opcode:
raise WebSocketError(
"The opcode in non-fin frame is expected to be zero, got {0!r}"
.format(f_opcode))
# Start reading a new message, reset the validator
self.utf8validator.reset()
self.utf8validate_last = (True, True, 0, 0)
opcode = f_opcode
elif f_opcode == self.OPCODE_CONTINUATION:
if not opcode:
raise WebSocketError("Unexpected frame with opcode=0")
elif f_opcode == self.OPCODE_PING:
self.handle_ping(header, payload)
continue
elif f_opcode == self.OPCODE_PONG:
self.handle_pong(header, payload)
continue
elif f_opcode == self.OPCODE_CLOSE:
self.handle_close(header, payload)
return
else:
raise WebSocketError(
"Unexpected opcode={0!r}".format(f_opcode))
if opcode == self.OPCODE_TEXT:
self.validate_utf8(payload)
message += payload
if header.fin:
break
if opcode == self.OPCODE_TEXT:
self.validate_utf8(message)
return message
else:
return bytearray(message)
def decode_header(cls, stream):
"""
Decode a WebSocket header.
:param stream: A file like object that can be 'read' from.
:returns: A `Header` instance.
"""
read = stream.read
data = read(2)
if len(data) != 2:
raise WebSocketError("Unexpected EOF while decoding header")
first_byte, second_byte = struct.unpack('!BB', data)
header = cls(fin=first_byte & cls.FIN_MASK == cls.FIN_MASK,
opcode=first_byte & cls.OPCODE_MASK,
flags=first_byte & cls.HEADER_FLAG_MASK,
length=second_byte & cls.LENGTH_MASK)
has_mask = second_byte & cls.MASK_MASK == cls.MASK_MASK
if header.opcode > 0x07:
if not header.fin:
raise WebSocketError(
'Received fragmented control frame: {0!r}'.format(data))
# Control frames MUST have a payload length of 125 bytes or less
if header.length > 125:
raise FrameTooLargeException(
'Control frame cannot be larger than 125 bytes: {0!r}'.
format(data))
if header.length == 126:
# 16 bit length
data = read(2)
if len(data) != 2:
raise WebSocketError('Unexpected EOF while decoding header')
header.length = struct.unpack('!H', data)[0]
elif header.length == 127:
# 64 bit length
data = read(8)
if len(data) != 8:
raise WebSocketError('Unexpected EOF while decoding header')
header.length = struct.unpack('!Q', data)[0]
if has_mask:
mask = read(4)
if len(mask) != 4:
raise WebSocketError('Unexpected EOF while decoding header')
header.mask = mask
return header
def send(self, message, binary=False):
"""
Send a frame over the websocket with message as its payload
"""
if binary is None:
binary = not isinstance(message, (str, unicode))
opcode = self.OPCODE_BINARY if binary else self.OPCODE_TEXT
try:
self.send_frame(message, opcode)
except WebSocketError:
raise WebSocketError("Socket is dead")
def handle_close(self, header, payload):
"""
Called when a close frame has been decoded from the stream.
:param header: The decoded `Header`.
:param payload: The bytestring payload associated with the close frame.
"""
if not payload:
self.close(1000, None)
return
if len(payload) < 2:
raise WebSocketError('Invalid close frame: {0} {1}'.format(
header, payload))
code = struct.unpack('!H', str(payload[:2]))[0]
payload = payload[2:]
if payload:
validator = Utf8Validator()
val = validator.validate(payload)
if not val[0]:
raise UnicodeError
if not self._is_valid_close_code(code):
raise WebSocketError('Invalid close code {0}'.format(code))
self.close(code, payload)
def receive(self):
"""
Read and return a message from the stream. If `None` is returned, then
the socket is considered closed/errored.
"""
if self._closed:
raise WebSocketError("Connection is already closed")
try:
return self.read_message()
except UnicodeError:
logger.info('websocket.receive: UnicodeError')
self.close(1007)
except WebSocketError:
logger.info('websocket.receive: WebSocketError')
self.close(1002)
except Exception, e:
logger.info('websocket.receive: Unknown error %s', e)
raise e
def send(self, message, binary=None):
try:
uwsgi.websocket_send(message)
except IOError, e:
self.close()
raise WebSocketError(e)