Bluetooth comms - make event driven

[jtullis]

This basic code accepts commands from my PC sent over BT. At the moment it just loops and loops waiting from strings to come through.

How do I get it to fire a function whenever a bluetooth string is received, so it can sit idle until something is received?

Thanks.

import socket

PCadd=('00:15:83:b7:08:57', 2)

sock=socket.socket(socket.AF_BT, socket.SOCK_STREAM)
target=(PCadd)
sock.connect(target)

print 'Connected to ' + str(PCadd)

while 1:
	data = sock.recv(1024);
	if not data: break
	print data
sock.close()

[raf1hh]

I was just looking at something similar. In theory it should work by using the following:
1. Threading
2. Callback function

Here is a sample that works on a pc:

import time
from threading import Thread

class Test(Thread):
    def __init__(self):
        self.callback = None
        self.id = 0
        Thread.__init__(self)

    def run(self):
        start = time.time()
        dif = time.time()-start
        i1 = time.time()
        while dif < 20:
            dif = time.time()-start

            i2 = time.time()
            if (i2-i1 > 1):
                i1 = time.time()
                #print i1
                self.callback("This is an event from thread: %s" % self.id)


def event_fired(*args):
    print args[0]

if __name__ == '__main__':
    start = time.time()
    t1 = Test()
    t1.id=1
    t1.callback = event_fired

    t2 = Test()
    t2.id=2
    t2.callback = event_fired

    t3 = Test()
    t3.id=3
    t3.callback = event_fired


    print "started"
    t1.start()
    t2.start()
    t3.start()

    t1.join()
    t2.join()
    t3.join()

    print "end"

[jtullis]

Sorry....I don't really get it! I don't know anything about threads etc on Python, or in any language for that matter. If anyone can explain I'd be grateful. I've read about a .listen function, but it's not documented in the 1.4.2 library reference.

[raf1hh]

Try this:

http://www.devshed.com/c/a/Python/Ba...ing-in-Python/

[Skarabeus]

Hello

Have you checked "select" módule?

This code must work for reading ip sockets but
i don't now about BT sockets.

import socket
import select

PCadd=('00:15:83:b7:08:57', 2)

sock=socket.socket(socket.AF_BT, socket.SOCK_STREAM)
target=(PCadd)
sock.connect(target)

print 'Connected to ' + str(PCadd)

timeout = 5 # 5 seconds
while 1:
        l = select.select([sock],[],[],timeout)
        if not l: continue
	data = sock.recv(1024);
	if not data: break
	print data
sock.close()

[qcalv]

Hi everyone,

Ive been playing with thread somehow to retrieve the bluetooth messages in an asynchronous way. Well after blocking the nokia n95 few times and even had to take the battery out, I would like some tips if anyone knows anything more about threads.

So Ive been playing with the code given here

Here is my code:

#single line comment
"""multiline comment"""

#Api importations
import sys
sys.path.append('e:\\python\\lib')
import e32 
import socket
import appuifw
from appuifw import *
import threading

class MyThread ( threading.Thread ):

	def run ( self ):
		global sock
		print 'Entered in thread'
		try:
			sock.send("Hello World")
			print 'no error while sending'
		except:
			print 'error while sending'
		print 'Leaved the thread'
		
def quit():
	global sock
	try:
		sock.close()
		appuifw.note(u"Socket aus.","info")
		app_lock.signal()
	except NameError:
		appuifw.note(u"Socket war nicht an.","info")
		app_lock.signal()

def connect():
	global sock
	sock=socket.socket(socket.AF_BT, socket.SOCK_STREAM)
	sock.connect(('00:0e:9b:d9:5d:a2',1))	

def launchThread():
	MyThread().start()


#Code implementation
menu=appuifw.app.menu=[	(u"Quit",quit),
						(u"Connect",connect),
						(u"Start Thread",launchThread)]

print 'Connection starting...'
connect() #connect to the computer id hyperterminal
print 'Wait to be connected...'
e32.ao_sleep(5) #wait to be sure to be connected
print 'Starting thread...'
app_lock=e32.Ao_lock()
appuifw.app.exit_key_handler=quit
MyThread().start()
app_lock.wait()
#end of the program

Basically everything goes well till Entered Thread, and then nothing happens, the Python Console freeze and I have to wait till the Python Console crashes, and basically just closes. No error message, nothing since it bugged. Could anyone help me on that, Im sure the problem comes from send(), because whatever I put in this thread it is working, but as soon as i put the send() method then, doesnt work anymore...

Cheers,

fran

[kandyfloss]

This basic code accepts commands from my PC sent over BT. At the moment it just loops and loops waiting from strings to come through.

How do I get it to fire a function whenever a bluetooth string is received, so it can sit idle until something is received?

Thanks.

import socket

PCadd=('00:15:83:b7:08:57', 2)

sock=socket.socket(socket.AF_BT, socket.SOCK_STREAM)
target=(PCadd)
sock.connect(target)

print 'Connected to ' + str(PCadd)

while 1:
	data = sock.recv(1024);
	if not data: break
	print data
sock.close()

Have you tried the any of the debugging techniques to find out due to which error the python shell is crashing?

You could use the exception harness method to do it, or any of the method from this article

[jtullis]

I wonder if

sock.send("Hello World")

needs a 'u' before the string?

sock.send(u"Hello World")

[qcalv]

So I tried the different debugging techniques, but the problem is that not any exception are thrown out, so impossible to catch them.

Here is my code...

try:
    # Actual program is here.
	#Code implementation
	menu=appuifw.app.menu=[	(u"Quit",quit),
							(u"Connect",connect),
							(u"Start Thread",launchThread)]
	# Set up the server:
	server = socket.socket ( socket.AF_BT, socket.SOCK_STREAM )
	adress='00:0e:9b:d9:5d:a2'
	app_lock=e32.Ao_lock()
	appuifw.app.exit_key_handler=quit
	print 'Connection starting...'
	server.connect((adress,1))
	#time=server.gettimeout()
	#print 'Time out', time
	print 'Wait to be connected...'
	e32.ao_sleep(5) #wait to be sure to be connected
	print 'Connected...'
	ClientThread ( server, adress ).start()
	print 'wait before going to wait!'
	e32.ao_sleep(10)
	print 'wait now hoping thread launched'
	app_lock.wait()
	#End of program
	1 / 0
except:
	import sys
	import traceback
	import e32
	import appuifw
	appuifw.app.screen="normal"               # Restore screen to normal size.
	appuifw.app.focus=None                    # Disable focus callback.
	body=appuifw.Text()
	appuifw.app.body=body                     # Create and use a text control.
	applock=e32.Ao_lock()
	def quit():applock.signal()
	appuifw.app.exit_key_handler=quit         # Override softkey handler.
	appuifw.app.menu=[(u"Exit", quit)]        # Override application menu.
	body.set(unicode("\n".join(traceback.format_exception(*sys.exc_info()))))
	applock.wait()                            # Wait for exit key to be pressed.
	appuifw.app.set_exit()

As u can see, i tried to put some temporisation to be sure everything is started, but anyway after seeing on the console the message: Received connection blabla, then everything freezes, i can barely go back to the menu of the nokia n95, and anyway python shell doesnt work any more, and still no error message?!

Anyone idea?

cheers,
fran

[reallife47]

I had seen somewhere a procedure that allowed to make a text file which would work as the error log?
Where could I find it?

Thanks

[croozeus]

I had seen somewhere a procedure that allowed to make a text file which would work as the error log?
Where could I find it?

Thanks

You could use the below code for that,

def main():
    try:
        Your main code goes here.
    except:
        import sys
        import traceback
        import appuifw
        cla, exc, trbk = sys.exc_info()
        excName = cla.__name__
        try:
            excArgs = exc.__dict__["args"]
        except KeyError:
            excArgs = "<no args>"
        excTb = traceback.format_tb(trbk, 5)
        errorString = repr(excName) + '-' + repr(excArgs) + '-' + repr(excTb) + '\n'
        print errorString
        appuifw.note(u'Application errors, see log file for more information', "error")
        file = open(u'C:\\Log.txt','a')
        file.write(errorString)
        file.close()
        raise
 
if __name__ == "__main__":
    main()

Errors would be recorded to C:\\Log.txt

Best Regards,
Croozeus

[JOM]

I had seen somewhere a procedure that allowed to make a text file which would work as the error log? Where could I find it?

I can recommend using "trace", sample code here by Yours Truly

Cheers,

--jouni

[croozeus]

I can recommend using "trace", sample code here by Yours Truly

Cheers,

--jouni

Aha, So we have one more debugging tool here

Jouni, I would be nice if you add this to the Wiki article having Python Debugging Techniques,


Best Regards,
Croozeus

[JOM]

Jouni, I would be nice if you add this to the Wiki article having Python Debugging Techniques

I know, I know... but it's a bit more complicated system, not just fixed lines to copy & paste in certain fixed location.

For example last night I was experimenting how to filter trace output, in order to keep the log file smaller and more useful. I should create a library, define API etc. However it was much more fun to write a new game

But definitely it's on my to-do list!

Cheers,

--jouni in Budapest