I was trying to write a protocol like UDP in python, which include some details like three_handshake, but I can't run the server.py cause it told me like this:
Traceback (most recent call last): File "/Users/suiyoucheng/PycharmProjects/9331 ASS/receiver.py", line 38, in <module> BYTE_fh, senderAddress = receiverSocket.recvfrom(1024) OSError: [Errno 57] Socket is not connected
and my server.py code shown as below:
try: receiverSocket = socket(AF_INET, SOCK_STREAM) except: print("Failed to create receiver socket.") sys.exit() receivePort = 2000 try: receiverSocket.bind(('', receivePort)) except: print("Bind failed.") sys.exit() # First Hand Shake # receiver_ISN = 0 receiver_ITIME = time.time() BYTE_fh, senderAddress = receiverSocket.recvfrom(1024) #**where I got wrong**# first_hand = pickle.loads(BYTE_fh)
Could you guys tell me how to fix that? Thank you so much.
You will need a client socket as well to test the server. Below is a more complete ClientSocket class that can be used. You can use the function cnsdrcv() for a one time send-receive interaction. The same class can also be used on the server-side for interacting with the client connections -
connection, client_address = serverSocket.accept() clntCon = ClientSocket() clntCon.useSocket(connection).connect() dataBytes = clntCon.rcvAllSent() # Process all the "dataBytes" and then respond back clntCon.send(responseBytes) clntCon.close() #---------------------------------------------------------------------------------------------------------- def cnsdrcv(host, port, data, timeout=1): # data - bytes() # returns data chunks as list of bytes() # Create a TCP/IP socket sock = ClientSocket() sock.useHost(host, port, timeout) try: sock.connect() # Send data sock.send(data) return sock.rcvUntilTimeout() finally: sock.close()
The complete class below -
class ClientSocket: def __init__(self, name=None): logging.debug("ClientSocket [{}] : __init__()".format(name)) self.Name = name self.sock = None self.server_address = None @property def Name(self): if self.__Name is None and self.server_address is not None: self.Name = str(self.server_address[1]) return self.__Name @Name.setter def Name(self, name): self.__Name = name @Name.deleter def Name(self): del self.__Name def useSocket(self, sock, timeout=1): # Socket is assumed to be already connected logging.debug("ClientSocket [{}] : useSocket()".format(self.Name)) if sock is None: raise ValueError("ClientSocket.useSocket() : sock arg cannot be None") if self.sock is None: self.server_address = sock.getpeername() self.sock = sock self.timeout = timeout self.sock.settimeout(self.timeout) return self else: raise AttributeError("ClientSocket.useSocket() : is already in use") def useHost(self, host, port, timeout=1): logging.debug("ClientSocket [{}] : useHost()".format(self.Name)) if host == None or len(host) == 0: host = socket.gethostname() self.server_address = (host, port) self.timeout = timeout def connect(self): logging.debug("ClientSocket [{}] : connect()".format(self.Name)) if self.sock is None: # Create a TCP/IP socket self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) logging.info('connecting to {} port {}'.format(*self.server_address)) # Connect the socket to the port where the server is listening self.sock.connect(self.server_address) self.sock.settimeout(self.timeout) else: self.isValid() def isValid(self): if not self.sock: return False try: if self.sock.fileno() == -1: except: return False try: self.sock.getsockname() except socket.error as e: if e.args[0] == errno.EBADF: # Socket is CLOSED pass return False try: self.sock.getpeername() except socket.error as e: if e.args[0] in [errno.EBADF, errno.ENOTCONN]: # Socket is CLOSED pass return False return True def send(self, data): # data must be a bytes or Data object logging.debug("ClientSocket [{}] : send()".format(self.Name)) logging.debug('sending {!r}'.format(data)) if not self.isValid() : logging.error("Client Socket in BAD state, cannot send") if isinstance(data, str): data = data.encode() try: # Send data self.sock.sendall(data) except: raise def rcvOnce(self, rcvSz, timeout=5): # receive at least one byte, waiting for timeout secs # returns bytes containing max rcvSz bytes logging.debug("ClientSocket [{}] : rcvOnce()".format(self.Name)) if not self.isValid() : logging.error("Client Socket in BAD state, cannot receive") return None strtTime = time.time() while True: try: chunk = self.sock.recv(rcvSz) break except socket.timeout: logging.debug("Socket recv timedout, re-trying") if time.time() - strtTime >= timeout: raise continue except: logging.exception("Receive exception") raise if chunk is None or len(chunk) == 0: logging.debug("Received len [0]") else: logging.debug("Received len [{}]".format(len(chunk))) return chunk def rcvAllSent(self, timeout=5): # Returns a Data object logging.debug("ClientSocket [{}] : rcvAllSent()".format(self.Name)) if not self.isValid() : logging.error("Client Socket in BAD state, cannot receive") return None chunks = [] strtTime = time.time() while True: try: chunk = self.sock.recv(1024) except socket.timeout as e: logging.debug("Read Timeout occurred [{}]".format(e)) if time.time() - strtTime >= timeout: raise continue except socket.error as e: logging.error("Some Socket error occurred [{}]".format(e)) break else: if len(chunk) == 0: logging.info("Received empty chunk, could be due to socket close()") break else: chunks.append(chunk) if len(chunk) < 1024: break else: continue return b''.join(chunks) def rcvUntilTimeout(self, rcvSz=2048): # returns a list of received bytes() objects logging.debug("ClientSocket [{}] : rcvUntilTimeout()".format(self.Name)) if not self.isValid() : logging.error("Client Socket in BAD state, cannot receive") return None chunks = [] tchunkb = [] chunk = self.rcvOnce(rcvSz) if chunk is None or len(chunk) == 0: # Socket closed by the remote return None else: chunks.append(chunk) while True: try: chunkb = self.sock.recv(rcvSz) except socket.timeout as e: logging.debug("Socket recv timedout") break except socket.error: logging.exception("Socket recv error") raise except: logging.exception("Unknown Exception while recv") raise else: if len(chunkb) == 0: logging.info("Received empty chunk indicating remote end closed the socket") break else: logging.debug("Received len [{}]".format(len(chunkb))) tchunkb.append(chunkb) if len(chunkb) < rcvSz: chunks.append(b''.join(tchunkb)) tchunkb = [] else: continue return chunks def close(self): logging.debug("ClientSocket [{}] : close()".format(self.Name)) if self.isValid(): self.sock.shutdown(socket.SHUT_RDWR) self.sock.close()
You need to start listening for connections before you can read the data from the socket. Please add receiverSocket.listen() and receiverSocket.accept() after the bind(). Rather than using raw socket, you can use the socketserver as well.
The overall steps that need to be taken for creating a server (without exception handling):
srvsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server_address = (socket.gethostname(), 25000) srvsock.bind(server_address) srvsock.listen(5) connection, client_address = srvsock.accept() data = connection.recv(1024)
