If you want to implement TCP/IP communication using sockets, you can use Python and the socket API. The socket API is a BSD
implementation and is well documented in the Python help system. Using sockets, you have to decide if your Scorpion application is going
to be the server or the client. This example shows how you can be a server. Example 31 shows a tcp/ip client.

Look in Central.Start for the initialization code which sets up the serversocket. Then look in the script socktrig
for the code that checks if a request is inbound on the serversocket. If so, a clientsocket is used for subsequent operation. If the client socket
is closed, a new incoming connection will be allowed. In this fashion the client can connect and close without any protocol handshakes.

What should the client side code look like? In Python you can use this script:

from socket import *
def Trigger():
    ip='localhost' 
    port=9901
    csock=socket(AF_INET,SOCK_STREAM)
    csock.settimeout(1.0) 
    csock.connect( (ip,port) )
    csock.send('PartPresent')
    print csock.recv(100)
    csock.close()

The example is contained in the example profile SocketServer.zip.  The example requires python 2.3 or higher to be installed.

Example : Socket Server - server side

Central Start

import sys
from socket import *
ip='localhost'
port=9901

ssock=socket(AF_INET,SOCK_STREAM)
ssock.settimeout(0.2)
ssock.bind ( (ip,port) )
ssock.listen(1)
csock=0
connected=0
tries=0

Central Stop

ssock.close()

SockTrig

# called from scheduler

def socktrig():

  import socket

  global csock
  global connected

  if connected:
    # socket is there
    try:
      msg=csock.recv(256)
      if msg=='':
         # socket closed
         print 'Client disconnected'
         csock.close()
         csock=0
         connected=0
      elif msg==GetValue('Trigger.Text'):   # contains PartPresent
        print 'PartPresent'
        ExecuteCmd('GrabExecute','')
      else:
        print 'Unknown command',msg
    except socket.timeout:
      pass                                  #no data in buffer yet, no error condition
    except:
      try:
        csock,addr=ssock.accept()
        csock.settimeout(0.2)
        print 'Client connected',addr
        connected=1
      except:
        print 'Timeout waiting for connection'
  else:
    # accept new connection if not connected
    try: 
      csock,addr=ssock.accept()
      csock.settimeout(0.2)
      print 'Client connected',addr
      connected=1
    except:
      print 'Still waiting for connection'

Sending response # sends message in external tool

global csock

if connected:csock.send(GetValue('ResponsePass.Text'))