#No ip duc port forwarding full#
No special knowledge about socket programming is needed, if you use our event-driven tcpcom package (see for full information). This is not really necessary in this situation, but usual for more complicated client/server applications.Įxperiment 2: Easy coding with an event-driven socket library The client also starts a thread to handle the incoming data.
#No ip duc port forwarding code#
Print "done" Highlight program code (Ctrl+C copy, Ctrl+V paste) Print "Connection to %s:%d failed" % (IP_ADDRESS, IP_PORT) Sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # - End of Receiver - def startReceiver():ĭebug( "sendCommand() with cmd = " + cmd) Raise Exception( "Exception from blocking sock.recv()") # - class Receiver - class Receiver(Thread):ĭata = "" while data != "\0": # reply with end-of-message indicator try:ĭebug( "Received data block from server, len: " + \
# DataClient1.py from threading import Thread The clients just sends a "go" about every 2 seconds and displays the server reply. Once the program works successfully, the verbose mode can be turned off. It is recommended to define a simple flag to enter a "debug mode", where verbose information is written to stdout. Normally the main program could enter the listening state and wait for another client, but in our program the main thread just "hangs" in a loop without doing something special. Then a SocketHandler thread is started that handles the connection with the client. The server enters the listening state by calling the blocking function serverSocket.accept() that returns with connect information when a link with a client is established. Highlight program code (Ctrl+C copy, Ctrl+V paste) # necessary to terminate it at program termination: HOSTNAME = "" # Symbolic name meaning all available interfaces try: tsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) ServerSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) State = "Button released" print "Reporting current state:", state If cmd = "go": # remove trailing "\0" if GPIO.input(P_BUTTON) = GPIO.LOW: Waiting for next client."ĭebug( "Calling executeCommand() with cmd: " + cmd) # happens when connection is reset from the peer breakĭebug( "Received cmd: " + cmd + " len: " + str(len(cmd))) # - class SocketHandler - class SocketHandler(Thread): P_BUTTON = 24 # adapt to your wiring def setup(): # DataServer1.py from threading import Thread In the most single arrangement client and server are connected to the same router and use the same IP segment.
The client then creates a client socket (the plug counterpart) and tries to establish a communication link to the server using its IP address and port number. We say that the server is "listening" for an incoming client. When the server starts, it creates a server socket (like a electrical plug) that uses a particular port and goes in a wait state. In addition, server and client specify one of 65536 communication channels (IP ports). In order to identify the two computers on the Internet, their IP address is used.
Rather, first the server program must be started before the client program can engage a connection to it. Most important and somewhat unexpected is the fact that the communication partners, the server and the client, are not symmetrical. In this chapter we show typical programs for simple TCP communication without going into much details (consult other tutorials about socket programming to acquire a full understanding). In most situations the data link is established via TCP/IP and the well-established client/server technology based on socket programming is used.
#No ip duc port forwarding Pc#
Information exchange between a program running on the Raspberry Pi and a partner program running on a remote computer systems becomes important when the Raspberry Pi is a front end of a measurement system and transfers sensor data in real-time to a control station or when a remote PC sends commands a RPi based robot (remote control mode).
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