#!/usr/bin/python2
# -*- coding: utf-8 -*-
# sudo pip install tornado
#
# Websocket example with tornade web server.
#
# Gerhard Hepp, 2017
#
import tornado.ioloop
import tornado.web
import tornado.websocket
import threading
import time
import Queue
# debug = True: set for a blink signal, no GPIO usage
# debug = False: set for GPIO usage
debug = False
if not debug:
import RPi.GPIO as GPIO
# messages from Periphaeral Class to Websocket
sendQueue= Queue.Queue()
class PeripheralDebug:
def __init__(self, sendQueue):
self.sendQueue = sendQueue
def start(self):
self.runit = True
blinkThread = threading.Thread(target=self.blink)
blinkThread.start()
def stop(self):
self.runit = False
def blink(self):
cnt = 0
while self.runit:
self.sendQueue.put( { 'data': 'on', 'cnt' : cnt } )
cnt += 1
time.sleep(0.5)
self.sendQueue.put( { 'data': 'off', 'cnt' : cnt } )
cnt += 1
time.sleep(0.5)
class PeripheralGPIO:
def __init__(self, sendQueue):
self.sendQueue = sendQueue
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
self.channel = 4
GPIO.setup(self.channel, GPIO.IN, pull_up_down=GPIO.PUD_UP)
def start(self):
self.runit = True
blinkThread = threading.Thread(target=self.run)
blinkThread.start()
def stop(self):
self.runit = False
def run(self):
cnt = 0
prev = None
while self.runit:
res = GPIO.input(self.channel)
if prev != res:
if res:
self.sendQueue.put( { 'data': 'on', 'cnt' : cnt } )
else:
self.sendQueue.put( { 'data': 'off', 'cnt' : cnt } )
cnt += 1
prev = res
# for debouncing and limiting number of events per time
time.sleep(0.01)
class PeripheralFactory:
@staticmethod
def getPeripheral(debug):
if debug:
return PeripheralDebug(sendQueue)
else:
return PeripheralGPIO(sendQueue)
peripheral = PeripheralFactory.getPeripheral(debug)
peripheral.start()
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write( """
Websocket sample
Sample connection to a Raspberry Pi
Connection Status
connection
Message display
message
""" )
runMessageSend = True
class ClientWebSocketHandler(tornado.websocket.WebSocketHandler):
def __init__(self, args, kwargs):
tornado.websocket.WebSocketHandler.__init__(self, args, kwargs)
print("ClientWebSocketHandler.init")
self.my_thread = threading.Thread(target = self.run)
self.my_thread.start()
def run(self):
while runMessageSend:
try:
s = sendQueue.get(block=True, timeout=0.1)
except Exception:
continue
if self.ws_connection is None:
print("discard ", s)
else:
print("send ", s)
try:
self.write_message(s )
except Exception:
pass
def open(self, *args, **kwargs):
print("open", args, kwargs)
def on_close(self, *args, **kwargs):
print ("on_close", args, kwargs)
def on_message(self, m):
print ( "received", m )
def make_app():
return tornado.web.Application(
[
(r"/" , MainHandler),
(r"/ws", ClientWebSocketHandler),
]
)
if __name__ == "__main__":
print("start")
app = make_app()
app.listen(8080)
try:
tornado.ioloop.IOLoop.current().start()
except KeyboardInterrupt:
peripheral.stop()
runMessageSend = False
tornado.ioloop.IOLoop.current().stop()
print("stopped")