move towards single implementation for socket client/server using asyncore and threads

datagram/UdpMulticastClient.py

@@ -0,0 +1,29 @@
+import socket
+import struct
+import sys
+
+multicast_group = '224.3.29.71'
+server_address = ('', 10000)
+
+# Create the socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+
+# Bind to the server address
+sock.bind(server_address)
+
+# Tell the operating system to add the socket to the multicast group
+# on all interfaces.
+group = socket.inet_aton(multicast_group)
+mreq = struct.pack('4sL', group, socket.INADDR_ANY)
+sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
+
+# Receive/respond loop
+while True:
+    print >>sys.stderr, '\nwaiting to receive message'
+    data, address = sock.recvfrom(1024)
+    
+    print >>sys.stderr, 'received %s bytes from %s' % (len(data), address)
+    print >>sys.stderr, data
+
+    print >>sys.stderr, 'sending acknowledgement to', address
+    sock.sendto('ack', address)

datagram/UdpMulticastServer.py

@@ -0,0 +1,39 @@
+import socket
+import struct
+import sys
+
+message = 'very important data'
+multicast_group = ('224.3.29.71', 10000)
+
+# Create the datagram socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+
+# Set a timeout so the socket does not block indefinitely when trying
+# to receive data.
+sock.settimeout(0.2)
+
+# Set the time-to-live for messages to 1 so they do not go past the
+# local network segment.
+ttl = struct.pack('b', 1)
+sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
+
+try:
+
+    # Send data to the multicast group
+    print >>sys.stderr, 'sending "%s"' % message
+    sent = sock.sendto(message, multicast_group)
+
+    # Look for responses from all recipients
+    while True:
+        print >>sys.stderr, 'waiting to receive'
+        try:
+            data, server = sock.recvfrom(16)
+        except socket.timeout:
+            print >>sys.stderr, 'timed out, no more responses'
+            break
+        else:
+            print >>sys.stderr, 'received "%s" from %s' % (data, server)
+
+finally:
+    print >>sys.stderr, 'closing socket'
+    sock.close()

datagram/UdpSender.py

@@ -0,0 +1,23 @@
+import socket
+import sys
+
+# Create a UDP socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+
+server_address = ('localhost', 10000)
+message = 'This is the message.  It will be repeated.'
+
+try:
+
+    # Send data
+    print >>sys.stderr, 'sending "%s"' % message
+    sent = sock.sendto(message, server_address)
+
+    # Receive response
+    print >>sys.stderr, 'waiting to receive'
+    data, server = sock.recvfrom(4096)
+    print >>sys.stderr, 'received "%s"' % data
+
+finally:
+    print >>sys.stderr, 'closing socket'
+    sock.close()

datagram/UdpServer.py

@@ -0,0 +1,21 @@
+import socket
+import sys
+
+# Create a TCP/IP socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+
+# Bind the socket to the port
+server_address = ('localhost', 10000)
+print >>sys.stderr, 'starting up on %s port %s' % server_address
+sock.bind(server_address)
+
+while True:
+    print >>sys.stderr, '\nwaiting to receive message'
+    data, address = sock.recvfrom(4096)
+    
+    print >>sys.stderr, 'received %s bytes from %s' % (len(data), address)
+    print >>sys.stderr, data
+    
+    if data:
+        sent = sock.sendto(data, address)
+        print >>sys.stderr, 'sent %s bytes back to %s' % (sent, address)