def client_send_message(client_socket, message):
"""
Send a message and try to get a receive
"""
messages.send_message(client_socket, message)
message = messages.read_message(client_socket)
echo("[Client] Received: %s", message)
def server_thread_target(server):
"""
Accept thread
"""
# creating a TCP/IP socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
# binding socket to specified address
server_socket.bind(server.__address)
# start listening for connections
server_socket.listen(2)
# accept connection loop
while server.__accept_connections:
server.__started.set()
# wait for client connection
connection_socket, connection_addr = server_socket.accept()
# since closing listening socket not forces accept to throw exception we need to check a flag
if server.__accept_connections:
# the server has connection with the client and we need to start a message loop
thread = threading.Thread(target = SimpleBlockingServer.server_connection_thread_target, args=[connection_socket, connection_addr])
server.__connections.append((thread, connection_socket))
thread.start()
echo("[Server] Client %s connected", connection_addr)
finally:
# closing the server socket
server_socket.close()
echo("[Server] Closing server socket")
def __server_stop_listening(self):
"""
Stop server from listening
"""
self.__accept_connections = False
try:
# we're making dummy connection to force the server socket accept connection and return from blocking op
closing_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
closing_socket.connect(self.__address)
closing_socket.close()
except:
echo("[Server] Could connect to Server. Looks like server is down or not stared")
def client1(address):
# creating socket ...
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# ... and connecting to the server
client_socket.connect(address)
# send hello message and receive echo
client_send_message(client_socket, "Hello")
# shutting down sending
client_socket.shutdown(socket.SHUT_WR)
# getting bye message from the server
echo("[Client] Received: %s", messages.read_message(client_socket))
# waiting for the server to shut down
if messages.read_message(client_socket) is None:
echo("[Client] Got EOF from Server")
client_socket.close()
def server_connection_thread_target(connection_socket, address):
"""
Client-Server message loop. Just receiving messages and echoing back to the client.
Special message "Bye" closes the connection
WARNING: we assume that clients don't abuse the connection, i.e a client should end the connection, not the server
"""
can_send = True
try:
while True:
# reading one message from the client
message = messages.read_message(connection_socket)
if message is None:
# message is None, that means that the client has stopped sending data to the server
echo("[Server] Got EOF from Client")
# in that case we can shutdown reading
connection_socket.shutdown(socket.SHUT_RD)
# lets check if the server shut down sending first
if can_send:
# send bye message to the client ...
messages.send_message(connection_socket, "Bye bye Client")
# ... and shut down sending
connection_socket.shutdown(socket.SHUT_WR)
# nothing to send, nothing to receive, we can leave the message loop now
break
echo("[Server] Received [%s]: %s", address, message)
# lets check if the server can send messages
if can_send:
# echoing message from the client
messages.send_message(connection_socket, message)
# if we received special message from the client
if message == "Bye":
# shut down sending to the client and start only to listen for the remaining client messages
connection_socket.shutdown(socket.SHUT_WR)
can_send = False
except Exception:
echo("[Server] Connection error")
finally:
echo("[Server] Closing socket")
# close the socket
connection_socket.close()
def client2(address):
# creating socket ...
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# ... and connecting to the server
client_socket.connect(address)
# send hello message and receive echo
client_send_message(client_socket, "Hello")
# send bye message
client_send_message(client_socket, "Bye")
# the server should sent EOF
if messages.read_message(client_socket) is None:
echo("[Client] Got EOF from server")
# shutting down read
client_socket.shutdown(socket.SHUT_RD)
# sending bye message to the server
messages.send_message(client_socket, "Bye bye Server")
messages.send_message(client_socket, "Have a good day")
client_socket.shutdown(socket.SHUT_WR)
client_socket.close()
