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PORestarting socket connection following client disconnect
 

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  1. PORestarting socket connection following client disconnect
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    <p>I have this code which listens/sends from/to a Scratch program with remote sensor connections enabled (e.g communicates by Port 42001 on 127.0.0.1)</p> <pre><code># This code is copyright Simon Walters under GPL v2 # This code is derived from scratch_handler by Thomas Preston # Version 5dev 11Aug08 Much better looping supplied by Stein @soilandreyes # and someone else @MCrRaspJam who've name I've forgotton! # Version 6dev - Moved Allon/AllOff to be processed before single pins :) # Vesion 7dev - start to tidy up changes # Vesion 8dev - use gpio-output system and broadcast allon, 1on system # V0.1 - change to 6 out 2 in and sanitise the code # V0.2 - from array import * import threading import socket import time import sys import struct import RPi.GPIO as GPIO GPIO.setmode(GPIO.BOARD) GPIO.setup(11,GPIO.OUT) GPIO.setup(12,GPIO.OUT) GPIO.setup(13,GPIO.OUT) GPIO.setup(15,GPIO.OUT) GPIO.setup(16,GPIO.OUT) GPIO.setup(18,GPIO.OUT) GPIO.setup(22,GPIO.IN,pull_up_down=GPIO.PUD_UP) GPIO.setup(7,GPIO.IN,pull_up_down=GPIO.PUD_UP) ''' from Tkinter import Tk from tkSimpleDialog import askstring root = Tk() root.withdraw() ''' PORT = 42001 DEFAULT_HOST = '127.0.0.1' #HOST = askstring('Scratch Connector', 'IP:') BUFFER_SIZE = 240 #used to be 100 SOCKET_TIMEOUT = 1 SCRATCH_SENSOR_NAME_INPUT = ( 'gpio-input0', 'gpio-input1' ) SCRATCH_SENSOR_NAME_OUTPUT = ( 'gpio-output0', 'gpio-output1', 'gpio-output2', 'gpio-output3', 'gpio-output4', 'gpio-output5' ) SCRATCH_BROADCAST_NAME_OUTPUT = ( '1on','1off','2on','2off','3on','3off','4on','4off','5on','5off','6on','6off' ) #Map gpio to real connector P1 Pins GPIO_PINS = array('i',[11,12,13,15,16,18,22,7]) GPIO_PIN_OUTPUT = array('i') GPIO_PIN_INPUT = array('i') print "Output Pins are:" for i in range(0,len(SCRATCH_SENSOR_NAME_OUTPUT)): print GPIO_PINS[i] GPIO_PIN_OUTPUT.append(GPIO_PINS[i]) print "Input Pins are:" for i in range(len(SCRATCH_SENSOR_NAME_OUTPUT),8): print GPIO_PINS[i] GPIO_PIN_INPUT.append(GPIO_PINS[i]) class ScratchSender(threading.Thread): #Not needed as its a Listening issue ... class ScratchListener(threading.Thread): def __init__(self, socket): threading.Thread.__init__(self) self.scratch_socket = socket self._stop = threading.Event() def stop(self): self._stop.set() def stopped(self): return self._stop.isSet() def physical_pin_update(self, pin_index, value): physical_pin = GPIO_PIN_OUTPUT[pin_index] print 'setting GPIO %d (physical pin %d) to %d' % (pin_index,physical_pin,value) GPIO.output(physical_pin, value) def run(self): #This is main listening routine while not self.stopped(): #time.sleep(0.1) # be kind to cpu try: data = self.scratch_socket.recv(BUFFER_SIZE) dataraw = data[4:].lower() print 'Length: %d, Data: %s' % (len(dataraw), dataraw) if len(dataraw) == 0: #This is probably due to client disconnecting #I'd like the program to retry connecting to the client time.sleep(2) except socket.timeout: print "sockect timeout" time.sleep(1) continue except: break if 'sensor-update' in dataraw: #gloablly set all ports if 'gpio-outputall' in dataraw: outputall_pos = dataraw.find('gpio-outputall') sensor_value = dataraw[(outputall_pos+16):].split() #print sensor_value[0] for i in range(len(SCRATCH_SENSOR_NAME_OUTPUT)): self.physical_pin_update(i,int(sensor_value[0])) #check for individual port commands for i in range(len(SCRATCH_SENSOR_NAME_OUTPUT)): if 'gpio-output'+str(i) in dataraw: #print 'Found '+ 'gpio-output'+str(i) outputall_pos = dataraw.find('gpio-output'+str(i)) sensor_value = dataraw[(outputall_pos+14):].split() #print sensor_value[0] self.physical_pin_update(i,int(sensor_value[0])) #Use bit pattern to control ports if 'gpio-pattern' in dataraw: #print 'Found gpio-outputall' num_of_bits = len(SCRATCH_SENSOR_NAME_OUTPUT) outputall_pos = dataraw.find('gpio-pattern') sensor_value = dataraw[(outputall_pos+14):].split() #print sensor_value[0] bit_pattern = ('0000000000000000'+sensor_value[0])[-num_of_bits:] #print 'bit_pattern %s' % bit_pattern for i in range(len(SCRATCH_SENSOR_NAME_OUTPUT)): #bit_state = ((2**i) &amp; sensor_value) &gt;&gt; i #print 'dummy gpio %d state %d' % (i, bit_state) physical_pin = GPIO_PIN_OUTPUT[i] if bit_pattern[-(i+1)] == '0': print 'setting GPIO %d (physical pin %d) low' % (i,physical_pin) GPIO.output(physical_pin, 0) else: print 'setting GPIO %d (physical pin %d) high' % (i,physical_pin) GPIO.output(physical_pin, 1) elif 'broadcast' in dataraw: #print 'received broadcast: %s' % data if 'allon' in dataraw: for i in range(len(SCRATCH_SENSOR_NAME_OUTPUT)): self.physical_pin_update(i,1) if 'alloff' in dataraw: for i in range(len(SCRATCH_SENSOR_NAME_OUTPUT)): self.physical_pin_update(i,0) for i in range(len(SCRATCH_SENSOR_NAME_OUTPUT)): #check_broadcast = str(i) + 'on' #print check_broadcast if str(i+1)+'on' in dataraw: self.physical_pin_update(i,1) if str(i+1)+'off' in dataraw: self.physical_pin_update(i,0) if 'pin' + str(GPIO_PIN_OUTPUT[i])+'on' in dataraw: GPIO.output(physical_pin, 1) if 'pin' + str(GPIO_PIN_OUTPUT[i])+'off' in dataraw: GPIO.output(physical_pin, 0) elif 'stop handler' in dataraw: cleanup_threads((listener, sender)) sys.exit() else: print 'received something: %s' % dataraw def create_socket(host, port): while True: try: print 'Trying' scratch_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) scratch_sock.connect((host, port)) break except socket.error: print "There was an error connecting to Scratch!" print "I couldn't find a Mesh session at host: %s, port: %s" % (host, port) time.sleep(3) #sys.exit(1) return scratch_sock def cleanup_threads(threads): for thread in threads: thread.stop() for thread in threads: thread.join() if __name__ == '__main__': if len(sys.argv) &gt; 1: host = sys.argv[1] else: host = DEFAULT_HOST # open the socket print 'Connecting...' , the_socket = create_socket(host, PORT) print 'Connected!' the_socket.settimeout(SOCKET_TIMEOUT) listener = ScratchListener(the_socket) sender = ScratchSender(the_socket) listener.start() sender.start() # wait for ctrl+c try: while True: time.sleep(0.5) except KeyboardInterrupt: cleanup_threads((listener, sender)) sys.exit() </code></pre> <p>The issue I'm having is in this section of code</p> <pre><code> def run(self): #This is main listening routine while not self.stopped(): #time.sleep(0.1) # be kind to cpu try: data = self.scratch_socket.recv(BUFFER_SIZE) dataraw = data[4:].lower() print 'Length: %d, Data: %s' % (len(dataraw), dataraw) if len(dataraw) == 0: #This is probably due to client disconnecting #I'd like the program to retry connecting to the client time.sleep(2) except socket.timeout: print "sockect timeout" time.sleep(1) continue except: break </code></pre> <p>If the client disconnects e.g Scratch is closed, I need this program to basically restart looking for a connection again and wait for Scratch to re-connect. Could I have some suggestions as to how to achieve this please as I am a python newbie regards Simon</p> <p>My solution was to use a global variable and change main loop structure</p> <pre><code> if len(dataraw) == 0: #This is probably due to client disconnecting #I'd like the program to retry connecting to the client #tell outer loop that Scratch has disconnected if cycle_trace == 'running': cycle_trace = 'disconnected' break </code></pre> <p>is used to break out of loop and</p> <pre><code>cycle_trace = 'start' while True: if (cycle_trace == 'disconnected'): print "Scratch disconnected" cleanup_threads((listener, sender)) time.sleep(1) cycle_trace = 'start' if (cycle_trace == 'start'): # open the socket print 'Starting to connect...' , the_socket = create_socket(host, PORT) print 'Connected!' the_socket.settimeout(SOCKET_TIMEOUT) listener = ScratchListener(the_socket) sender = ScratchSender(the_socket) cycle_trace = 'running' print "Running...." listener.start() sender.start() # wait for ctrl+c try: #just pause time.sleep(0.5) except KeyboardInterrupt: cleanup_threads((listener,sender)) sys.exit() </code></pre> <p>this is now my main outer loop Seems to work :)</p>
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    1. COHave you tried calling `create_socket()` and replacing corresponding sockets in ScratchSender/Listener on disconnect?
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    2. COCould you give me some example code please as I am a python newbie and most of the code above (well the tricky socket/thread bits) was written by someone else :)
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