Socket and thread issues with UI programming

[mcloke74]

Hi there,

I've had a good, but frustrating, weekend trying to do a bit of client / server socket communication betweem my phone and my pc.

I am trying to write an app (similar to something described in the PyS60 documentation) that has a UI in the main thread and a socket listening in another thread. When the listening thread receives information it should notify the UI via a callback. I have studied both the rssreader.py example and the applicationskeleton example.py to lead where I am going

The problem i have is that once the connection has been made (and despite launching a new thread for this purpose) the UI no longer responds (to either softkeys) and I can't exit the application. I end up having to restart my phone to regain control (I can't run under an emulator as the connection is over bluetooth and I am connecting to a machine not supported by Nokias emulators :-(.

I have done a number of google searches and whilst the PythonGotchas page (on the post neo wiki) has a topic called Series60Threading, the resultant page has been spammed and there is no useful information.

Can someone take a look below and let me know what I am doing wrong. In my head I am either getting my socket programming mixed up or I have forgotten how to do threading as I have been using J2EE containers for too long!

Thanks in advance and thanks for producing something that has let me lose my weekend :-)


import e32
import appuifw, socket

commands = {1:'hello'}

class UnSunkClientListener:
def __init__(self, target):
self.lock=e32.Ao_lock()
self.callbacks=[]
self.target = target
self.soc = socket.socket(socket.AF_BT, socket.SOCK_STREAM)

def registerCallback(self, callback):
self.callbacks.append(callback)

def _notifyCallbacks(self, *args):
for x in self.callbacks:
x(*args)

def _process(self):
while 1:
op = self.soc.recv(1)
print op

def connect(self):
self.soc.connect(self.target)
import thread
if e32.is_ui_thread() == True:
self.t = thread.start_new_thread(self._process, ())

def disconnect(self):
self.t.exit()
self.soc.disconnect()

class UnSunkClientUI:
def __init__(self):
self.lock = e32.Ao_lock()
self.exitFlag=False
self.oldExitKeyHandler=appuifw.app.exit_key_handler
self.oldAppBody=appuifw.app.body
self.oldTitle=appuifw.app.title
appuifw.app.title=u'UnSunk Client'
appuifw.app.exit_key_handler = self.abort
appuifw.app.menu=[(u"Connect...", self.connect)]

def run(self):
try:
self.lock.wait()
while not self.exitFlag:
self.refresh()
self.lock.wait()
finally:
self.close()

def close(self):
appuifw.app.menu = []
appuifw.app.body = self.oldAppBody
appuifw.app.exit_key_handler = self.oldExitKeyHandler
appuifw.app.title = self.oldTitle

def notify(self, context):
#invoked when action happens from the listener
self.lock.signal()
pass

def refresh(self):
#update UI following an update
pass

def connect(self):
address,services=socket.bt_discover()
if len(services)>1:
choices=services.keys()
choices.sort()
choice=appuifw.popup_menu([unicode(services[x])+": "+x for x in choices],u'Choose port:')
target=(address,services[choices[choice]])
else:
target=(address,services.values()[0])
self.listener = UnSunkClientListener(target)
self.listener.registerCallback(self.notify)
self.listener.connect()
appuifw.app.menu=[(u"Disconnect", self.disconnect),(u"Exit", self.abort)]

def disconnect(self):
self.listener.disconnect()
appuifw.app.menu=[(u"Connect...", self.connect)]

def abort(self):
# Exit-key handler.
self.exitFlag = True
self.lock.signal()


def main():
client = UnSunkClientUI()
client.run()

if __name__ == "__main__":
main()

[mcloke74]

Ok, so I didn't seem to get much response to this ;-) Therefore I'll ask the question in another way, does anyone have any examples (other than the rssreader or applicationskeleton) that shows threading and socket interaction?

Alternatively, what documentation can I read as I am obviously mis understanding what is in the documentation bundled with the Python release.

Thanks in advance

M

[yemir]

Your listener class creates a socket in one thread and then tries to receive from it in another. This is not allowed; you can't share file descriptors between threads.

-Ken

[mcloke74]

Ken,

Thanks for the tip, I'll re-structure the code and see what happens next.

M