first draft of pyPlcTcpSocket

.gitignore

@@ -1,2 +1,3 @@
 /__pycache__/
 /doc/*.jar
+*.bat

demo_socket.py

@@ -1,43 +0,0 @@
-
-# explanation of socket handling:
-# https://realpython.com/python-sockets/
-#
-
-import socket
-import select
-
-
-
-print("Press Ctrl-Break for aborting")
-
-TCP_IP = 'fe80::e0ad:99ac:52eb:85d3'
-TCP_PORT = 15118 # The port for CCS
-BUFFER_SIZE = 1024  # Normally 1024
-
-ourSocket = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
-ourSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-
-ourSocket.bind((TCP_IP, TCP_PORT))
-ourSocket.listen(1)
-print("listening on port " + str(TCP_PORT))
-
-# example from https://stackoverflow.com/questions/5308080/python-socket-accept-nonblocking
-read_list = [ourSocket]
-while True:
-    # The select() function will block until one of the socket states has changed.
-    # We specify a timeout, to be able to run it in the main loop.
-    print("before select")
-    readable, writable, errored = select.select(read_list, [], [], 0.5)
-    for s in readable:
-        if s is ourSocket:
-            client_socket, address = ourSocket.accept()
-            read_list.append(client_socket)
-            print("Connection from", address)
-        else:
-            data = s.recv(1024)
-            if data:
-                print("received data:", data)
-            else:
-                print("connection closed")
-                s.close()
-                read_list.remove(s)

pyPlcTcpSocket.py

@@ -0,0 +1,163 @@
+
+# Server on a non-blocking socket
+#
+# explanation of socket handling:
+# https://docs.python.org/3/howto/sockets.html
+# https://realpython.com/python-sockets/
+# https://stackoverflow.com/questions/5308080/python-socket-accept-nonblocking
+#
+
+
+import socket
+import select
+import sys # for argv
+import time # for time.sleep()
+
+class pyPlcClientSocket():
+    def __init__(self):
+        self.sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+        self.isConnected = False
+        
+    def connect(self, host, port):
+        try:
+            self.sock.connect((host, port))
+            self.isConnected = True
+        except:
+            self.isConnected = False
+            
+    def mysend(self, msg):
+        totalsent = 0
+        MSGLEN = len(msg)
+        while (totalsent < MSGLEN) and (self.isConnected):
+            try:
+                sent = self.sock.send(msg[totalsent:])
+                if sent == 0:
+                    self.isConnected = False
+                    raise RuntimeError("socket connection broken")
+                totalsent = totalsent + sent
+            except:
+                self.isConnected = False
+    def isRxDataAvailable(self):
+        # todo
+        # ... = self.sock.recv(..., 2048))
+        return 0
+
+class pyPlcTcpServerSocket():
+    def __init__(self):
+        self.ipAdress = 'fe80::e0ad:99ac:52eb:85d3'
+        self.tcpPort = 15118 # The port for CCS
+        self.BUFFER_SIZE = 1024  # Normally 1024
+        # Concept explanation:
+        # We create a socket, that is just listening for incoming connections.
+        # Later in the cyclic loop, we use the "select" to wait for activity on this socket.
+        # In case there is a connection request, we create a NEW socket, which will handle the
+        # data exchange. The original socket is still listening for further incoming connections.
+        # This would allow to handle multiple connections.
+        self.ourSocket = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
+        self.ourSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        self.ourSocket.bind((self.ipAdress, self.tcpPort))
+        self.ourSocket.listen(1)
+        print("pyPlcTcpSocket listening on port " + str(self.tcpPort))
+        self.read_list = [self.ourSocket]
+        self.rxData = []
+        
+    def isRxDataAvailable(self):
+        return (len(self.rxData)>0)
+        
+    def getRxData(self):
+        # provides the received data, and clears the receive buffer
+        d = self.rxData
+        self.rxData = []
+        return d
+        
+    def transmit(self, txMessage):
+        numberOfSockets = len(self.read_list)
+        if (numberOfSockets!=2):
+            print("we have " + str(numberOfSockets) + ", we should have 2, one for accepting and one for data transfer. Will not transmit.")
+            return -1
+        totalsent = 0
+        MSGLEN = len(txMessage)
+        while totalsent < MSGLEN:
+            sent = self.read_list[1].send(txMessage[totalsent:])
+            if sent == 0:
+                print("socket connection broken")
+                return -1
+            totalsent = totalsent + sent
+        return 0
+        
+    def mainfunction(self):
+        # The select() function will block until one of the socket states has changed.
+        # We specify a timeout, to be able to run it in the main loop.
+        # print("before select")
+        timeout_s = 0.05 # 50ms
+        readable, writable, errored = select.select(self.read_list, [], [], timeout_s)
+        for s in readable:
+            if s is self.ourSocket:
+                # We received a connection request at ourSocket.
+                # -> we create a new socket (named client_socket) for handling this connection.
+                client_socket, address = self.ourSocket.accept()
+                # and we append this new socket to the list of sockets, which in the next loop will be handled by the select.
+                self.read_list.append(client_socket)
+                print("Connection from", address)
+            else:
+                # It is not the "listener socket", it is an above created "client socket" for talking with a client.
+                # Let's take the data from it:
+                try:
+                    data = s.recv(1024)
+                except:
+                    # The client closed the connection in the meanwhile.
+                    #print("The client closed the connection in the meanwhile.")
+                    data = None
+                if data:
+                    print("received data:", data)
+                    self.rxData = data
+                else:
+                    print("connection closed")
+                    s.close()
+                    self.read_list.remove(s)    
+
+
+
+
+def testServerSocket():
+    print("Testing the pyPlcTcpServerSocket...")
+    s = pyPlcTcpServerSocket()
+    print("Press Ctrl-Break for aborting")
+    nLoops = 0
+    while True:
+        s.mainfunction()
+        nLoops+=1
+        if ((nLoops % 10)==0):
+            print(str(nLoops) + " loops")
+            if (s.isRxDataAvailable()):
+                d = s.getRxData()
+                print("received " + str(d))
+                msg = "ok, you sent " + str(d)
+                s.transmit(bytes(msg, "utf-8"))
+
+def testClientSocket():
+    print("Testing the pyPlcTcpClientSocket...")
+    c = pyPlcClientSocket()
+    c.connect('fe80::e0ad:99ac:52eb:85d3', 15118)
+    print("connected="+str(c.isConnected))
+    print("sending something to the server")
+    c.mysend(bytes("Test", "utf-8"))
+    print("waiting 3s")
+    time.sleep(3)
+    if (c.isRxDataAvailable()):
+                d = c.getRxData()
+                print("received " + str(d))
+    print("end")
+
+
+if __name__ == "__main__":
+    if (len(sys.argv) == 1):
+        print("Use command line argument c for clientSocket or s for serverSocket")
+        exit()
+    if (sys.argv[1] == "c"):
+        testClientSocket()
+        exit()
+    if (sys.argv[1] == "s"):
+        testServerSocket()
+        exit()
+    print("Use command line argument c for clientSocket or s for serverSocket")