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npyscreen EXAMPLE of a socket connection updating widgets
#!/usr/bin/env python
import npyscreen, curses
# Incorporates code
# from http://www.binarytides.com/python-socket-server-code-example/
# Socket server in python using select function
import socket, select
class MyTestApp(npyscreen.NPSAppManaged):
# socket code
def onStart(self):
self.keypress_timeout_default = 1
self.addForm("MAIN", MainForm, name="Screen 1", color="IMPORTANT",)
self.addForm("SECOND", MainForm, name="Screen 2", color="WARNING", )
# socket code
self.CONNECTION_LIST = [] # list of socket clients
self.RECV_BUFFER = 4096 # Advisable to keep it as an exponent of 2
PORT = 5000
self.server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# this has no effect, why ?
self.server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.server_socket.bind(("0.0.0.0", PORT))
self.server_socket.listen(10)
# Add server socket to the list of readable connections
self.CONNECTION_LIST.append(self.server_socket)
self.sent=""
self.received="Chat server started on port " + str(PORT)
self.currentform = None
def while_waiting(self):
# Get the list sockets which are ready to be read through select
read_sockets,write_sockets,error_sockets = select.select(self.CONNECTION_LIST,[],[],0.01)
for sock in read_sockets:
#New connection
if sock == self.server_socket:
# Handle the case in which there is a new connection recieved through self.server_socket
sockfd, addr = self.server_socket.accept()
self.CONNECTION_LIST.append(sockfd)
self.received = "Client (%s, %s) connected" % addr
#Some incoming message from a client
else:
# Data recieved from client, process it
try:
#In Windows, sometimes when a TCP program closes abruptly,
# a "Connection reset by peer" exception will be thrown
data = sock.recv(self.RECV_BUFFER)
# echo back the client message
if data:
response = 'OK ... ' + data
sock.send(response)
self.sent = response
self.received = data
# client disconnected, so remove from socket list
except:
#print "Client (%s, %s) is offline" % addr
sock.close()
self.CONNECTION_LIST.remove(sock)
continue
def onCleanExit(self):
npyscreen.notify_wait("Goodbye!")
self.server_socket.close()
def change_form(self, name):
self.switchForm(name)
self.resetHistory()
class MainForm(npyscreen.ActionForm):
def create(self):
self.keypress_timeout_default = 1
self.add(npyscreen.TitleText, name = "Text:", value= "Press ^T to change screens" )
self.sentfield = self.add(npyscreen.TitleText, name = "Sent:", value="", editable=False )
self.receivedfield = self.add(npyscreen.TitleText, name = "Received:", value="", editable=False )
self.add_handlers({"^T": self.change_forms})
def while_waiting(self):
self.sentfield.value = self.parentApp.sent
self.receivedfield.value = self.parentApp.received
self.sentfield.display()
self.receivedfield.display()
def on_ok(self):
# Exit the application if the OK button is pressed.
self.parentApp.switchForm(None)
def change_forms(self, *args, **keywords):
if self.name == "Screen 1":
change_to = "SECOND"
else:
change_to = "MAIN"
# Tell the MyTestApp object to change forms.
self.parentApp.change_form(change_to)
def main():
TA = MyTestApp()
TA.run()
if __name__ == '__main__':
main()
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