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Johan1151
Posts: 4
Joined: Tue Jun 12, 2018 6:52 pm

websocket error

Fri Jun 15, 2018 8:23 pm

Hi, trying to get websocket up and running but getting this error (see image)
the server is starting without error, but webpage isn't loaded.

Image

here is the code of the server:

Code: Select all

 #! /usr/bin/python

import os.path
import tornado.httpserver
import tornado.websocket
import tornado.ioloop
import tornado.web
import RPi.GPIO as GPIO
import datetime
import json
import time
from time import sleep             # lets us have a delay  


#Initialize Raspberry PI GPIO
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)

GPIO.setup(17, GPIO.OUT, initial=1)    # LED
GPIO.setup(4, GPIO.IN, pull_up_down=GPIO.PUD_UP)    # BUTTON

	
class WSHandler(tornado.websocket.WebSocketHandler):
  def open(self):
    self.connected = True    
    print("New Connection.")
    self.write_message("LED = "+ str(GPIO.input(17))) 
    self.write_message("Connection was Opened.")
    self.timeout_loop()

  def on_message(self, message):
    print("Incoming message:", message)
    if message == "led on":   
      GPIO.output(17, False)
      self.write_message("LED = "+ str(GPIO.input(17)))
    elif message == "led off":
      GPIO.output(17, True)
      self.write_message("LED = "+ str(GPIO.input(17)))

	 
  def on_close(self):
    self.connected = False
    print("Connection was closed.")

  def timeout_loop(self):
    if self.connected:
      if GPIO.input(4) == 0:
        print("Button pressed")
        self.write_message("pressed button")
      tornado.ioloop.IOLoop.instance().add_timeout(datetime.timedelta(seconds=.1), self.timeout_loop)


application = tornado.web.Application([
  (r'/mycode', WSHandler),
  ])


if __name__ == "__main__":
    try:
        GPIO.output(17, True)
        http_server = tornado.httpserver.HTTPServer(application)
        http_server.listen(8888)
        main_loop = tornado.ioloop.IOLoop.instance()
 	
        print("Tornado Server started")
        main_loop.start()

    except:
        print("Exception triggered - Tornado Server stopped.")
        GPIO.cleanup()

#End of Program

Code Webform:

Code: Select all

 <html>

<head>
<title> Art1 - Websocket </title>
 <meta charset="UTF-8">
 <script src="jquery-1.11.0.min.js"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1">      

<style type="text/css">

</style>     
   
<script>   
   var ws = new WebSocket("ws://192.168.1.131:8888/mycode");
   ws.onopen = function(evt) {
     $("#log").text("Opening the websocket...");
   }
   ws.onmessage = function(evt) {
     $("#log").text(evt.data);
     var n = evt.data.search("=");
	 LEDs = parseInt((evt.data).substring(n+2));
     if(((evt.data).substring(0, n-1))== "LED"){
	   if(!LEDs){
	      $("#led1_on").hide();    $("#led1_on_build").hide();   
	      $("#led1_off").show();    $("#led1_off_build").show();   
	   }
	   else{
	      $("#led1_on").show();    $("#led1_on_build").show();   
	      $("#led1_off").hide();    $("#led1_off_build").hide();   
	   }

	   if(!LEDs){
	      $("#t1_on").hide();    $("#t1_off").show();      
	   }
	   else{
	      $("#t1_on").show();    $("#t1_off").hide();   
	   }
     }	   
   }		
   ws.onclose = function(evt) {
     $("#log").text("Connection Closed...");
   }
   function test(y) {
      ws.send(y);
	}

</script>   
   
 </head>

<body>

<h2>Play with Relay's <i><br><small><small>(Python & Tornado)</small></small></i></h2>
	<p><img id = "led1_on_bild" src="ON.jpg" width="92" height="146"/></p>
	<p><button id = "led1_on" style="color: #aaa" onclick="test('led1 off');">LED 1 is &nbsp ON</button></p>

	<p><img id = "led1_off_bild" src="OFF.jpg" width="92" height="146"/></p>
	<p><button id = "led1_off" style="color: #aaa" onclick="test('led1 on');">LED 1 is OFF</button></p>

<b>Drukknop:</b>
	<p><img id = "t1_on" src="button.jpg" width="30" height="30"/></p>
	<p><img id = "t1_off" src="button_off.jpg" width="30" height="30"/></p>
	

<b>Message:</b>
   <div id="log" style="overflow: auto; position: absolute ;overflow-x: hidden;
    width: 350px; height: 30px; background-color: #c2c7af">...</div>

<br><br>

</body>

</html>
Image
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ghp
Posts: 1517
Joined: Wed Jun 12, 2013 12:41 pm
Location: Stuttgart Germany
Contact: Website

Re: websocket error

Sat Jun 16, 2018 4:58 pm

Hello,
there are some problems in your code. See the annotations in the attached sample

Code: Select all

    
class WSHandler(tornado.websocket.WebSocketHandler):
    #
    # there is no server for the http-page
    # so you need to have this feature
    #
    def check_origin(self, origin):
        return True    
    
    def open(self):
        self.connected = True    
        print("New Connection.")
        
        # think no messages allowed in 'open', and do not start a loop ??
        #    self.write_message("LED = "+ str(GPIO.input(17))) 
        #    self.write_message("Connection was Opened.")
        #    self.timeout_loop()

    def on_message(self, message):
        print("Incoming message:", message)
        if message == "led on":   
            GPIO.output(17, False)
            self.write_message("LED = "+ str(GPIO.input(17)))
        elif message == "led off":
            GPIO.output(17, True)
        self.write_message("LED = "+ str(GPIO.input(17)))

     
    def on_close(self):
        self.connected = False
        print("Connection was closed.")

    # do not run a loop, but use threading and the async features in tornado
    def timeout_loop(self):
        if self.connected:
            if GPIO.input(4) == 0:
                print("Button pressed")
                self.write_message("pressed button")
            tornado.ioloop.IOLoop.instance().add_timeout(datetime.timedelta(seconds=.1), self.timeout_loop)



def make_app():
    #
    # create an application and not only a httpserver
    #
    return tornado.web.Application([
        (r"/mycode", WSHandler),
    ], debug=True)

if __name__ == "__main__":
    try:
        GPIO.output(17, True)
        app = make_app()
        app.listen(8888)
        main_loop = tornado.ioloop.IOLoop.instance()
     
        print("Tornado Server started")
        main_loop.start()

    except:
        print("Exception triggered - Tornado Server stopped.")
        GPIO.cleanup()

#End of Program
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