class ClientHandler(threading.Thread):
"""
Handles communication;
Communication is divided in two parts:
1.authentication
2.actual data transfer
Main logic is in the `run` function
"""
FIRT_MESSAGE = '200 LOGIN\r\n'
TIMEOUUT = '501 SYNTAX ERROR\r\n'
PASSWORD_MESSAGE = '201 PASSWORD\r\n'
SECOND_MESSAGE = '202 OK\r\n'
LOGIN_FAILED = '500 LOGIN FAILED\r\n'
SYNTAX_ERROR = '501 SYNTAX ERROR\r\n'
TIMEOUT = '502 TIMEOUT\r\n'
BAD_CHECKSUM = '300 BAD CHECKSUM\r\n'
def __init__(self, connection: socket):
self.time_start = time.time()
self.connection = connection
self.buffer = Buffer(connection)
self.step = 0
self.username = None
self.stop_event = threading.Event()
self.username_wrong = None
self.start_time = time.time()
t = threading.Timer(30, self.after_done)
t.start()
super().__init__()
def after_done(self):
"""
Callback, gets called 45 sec after start of communication
"""
if self.stop_event.is_set():
return
self.end_with_message(self.TIMEOUUT)
def end_with_message(self, message):
"""
:param message: msg to be sent
send message, close connection
"""
self.stop_event.set()
self.connection.sendall(message.encode())
self.connection.close()
self.stop_event.set()
def send_message(self, message: str):
self.connection.sendall(message.encode())
def run(self, ):
"""
main logic, close thread on return
:return:
"""
try:
if not self.handle_login():
self.end_with_message(self.LOGIN_FAILED)
return
except ConnectionLost:
print('---[CONNECTION LOST]-----' + str(self.ident) + '---' * 5)
return
while not self.stop_event.is_set():
if time.time() - self.start_time >= (45
if settings.AWS else 1000000):
time.sleep(0.5)
self.end_with_message(self.TIMEOUT)
break
try:
time.sleep(0.5)
self.handle_command()
except FotoException:
time.sleep(0.5)
self.end_with_message(self.SYNTAX_ERROR)
break
except PhotoLengthNotNumber:
time.sleep(0.5)
self.end_with_message(self.SYNTAX_ERROR)
break
except BadCheckSum:
self.send_message(self.BAD_CHECKSUM)
except WrongSyntax:
time.sleep(0.5)
self.end_with_message(self.SYNTAX_ERROR)
break
except ConnectionLost:
print('---[CONNECTION LOST]' + str(self.ident) + '---' * 5)
break
return
def handle_login(self):
"""
reads username and password; performs validation based on the sum of the username
:return: True on username == password
"""
try:
self.send_message(self.FIRT_MESSAGE)
username = self.buffer.read_username()
print(str(username) + '+++++' + str(self.ident))
self.send_message(self.PASSWORD_MESSAGE)
password = self.buffer.read_password(
aprox_length=len(str(username)))
print(str(password) + '!!!!!!' + str(self.ident))
try:
if password == username and username >= 518: #Robot not in username
self.send_message(self.SECOND_MESSAGE)
return True
else:
return False
except WrongPassword:
return False
except OSError or TypeError:
# print('---' * 5 + str(self.ident) + '---' * 5)
raise ConnectionLost
def handle_command(self):
"""
handle according command, throw Exception on wrong syntax
"""
while True:
curr_byte = self.buffer.read_byte()
if curr_byte == '':
raise WrongSyntax()
if not self.buffer.possible_start_info(
) and not self.buffer.possible_start_photo():
raise WrongSyntax()
elif self.buffer == b'INFO ':
try:
self.handle_info()
except BlockingIOError:
self.end_with_message(self.SYNTAX_ERROR)
break
elif self.buffer == b'FOTO ':
self.handle_photo()
break
elif len(self.buffer) > 5:
raise WrongSyntax()
def handle_photo(self):
"""
Reads FOTO msg: number of bytes to read, data, checksum
Performs validation of checksum and data checksum;
saves the photo in the file named according to thread ident
"""
with open(f'out{self.ident}', 'wb') as f:
bytes_to_read = self.buffer.read_photo_length()
read_bytes = 0
checksum = 0
while read_bytes < bytes_to_read:
try:
byte = self.buffer.read_byte(MSG_DONTWAIT, fake=True)
except BlockingIOError:
self.end_with_message(self.SYNTAX_ERROR)
f.write(byte)
checksum += ord(byte)
read_bytes += 1
sent_checksum = bytearray()
for i in range(4):
try:
byte = self.buffer.read_byte(fake=True)
except BlockingIOError:
raise BadCheckSum()
sent_checksum.extend(byte)
parsed_checksum = struct.unpack('>HH', sent_checksum)
parsed_checksum = str(parsed_checksum[0]) + str(parsed_checksum[1])
parsed_checksum = int(parsed_checksum)
# if not settings.AWS: # this thingy is in settings module, telnet sends \r\n at the end of every message
# for i in range(2):
# self.buffer.read_byte(fake=True)
if parsed_checksum == checksum:
self.send_message(self.SECOND_MESSAGE)
else:
raise BadCheckSum()
def handle_info(self):
"""
read info msg
saves the msg in the file named according to thread ident
"""
try:
self.buffer.read_line()
print((f'[INFO] -- {self.ident}', self.buffer.buffer))
with open(f'out{self.ident}', 'wb') as f:
f.write(self.buffer.buffer + b' [INFO]')
self.buffer.buffer = bytearray()
self.send_message(self.SECOND_MESSAGE)
except PhotoLengthNotNumber:
self.end_with_message(self.SYNTAX_ERROR)
except OSError:
print(f'---exc in read info---')
self.send_message(self.SECOND_MESSAGE)
