Thread WebSocketServer

jobbyworld

Dear pythonist,
Have trouble for writing threaded WebSocketEchoServer :
Code working without thread.
Code working with thread but hang somme times with
"ERROR A stack overflow in task Thread has been detected. "

If anyone knows more me about thread and how to debug

Thanks for any help
cheers !!
Here my file "wsServer.py" :


from hashlib import sha1

from ubinascii import b2a_base64 as b64encode
import sys
 
from time import sleep_ms
import micropython
import socket
import struct
import ujson
from struct import unpack,calcsize
from network import Server
from _thread import *
micropython.alloc_emergency_exception_buf(100)

FIN    = 0x80
OPCODE = 0x0f
MASKED = 0x80
PAYLOAD_LEN = 0x7f
PAYLOAD_LEN_EXT16 = 0x7e
PAYLOAD_LEN_EXT64 = 0x7f

OPCODE_TEXT = 0x01
CLOSE_CONN  = 0x8



def handshake(client):
	header=b""
	while header.find(b'\r\n\r\n') == -1:
		header += client.recv(16)
	#print(header.decode())
	lines = header.split(b"\r\n")
	d=dict()
	for line in lines[1:]:
		if not line :continue
		header,value = line.split(b": ",1)
		d[header]=value

	key = d[b'Sec-WebSocket-Key'].decode()

	# compute Response Key
	GUID = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
	hash = sha1(key.encode() + GUID.encode())
	d=hash.digest()
	response_key = b64encode(d).strip().decode('ASCII')
	template='HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: %s\r\n\r\n'
	handshake=template%response_key
	client.send(handshake.encode())
	print("handshake Done")

def sendMessage(client,message):
	global lock
	header  = bytearray()
	payload = message.encode('UTF-8')
	payload_length = len(payload)
	if payload_length <= 125:
		header.append(FIN | OPCODE_TEXT)
		header.append(payload_length)
	#with lock:
	client.send(header + payload)

def readMessage(client,callback=lambda msg:print("receveid ",msg)):
	b1, b2 = client.recv(2)
	fin    = b1 & FIN
	opcode = b1 & OPCODE
	masked = b2 & MASKED
	payload_length = b2 & PAYLOAD_LEN
	if payload_length == 126:
		#with lock:
		payload_length = struct.unpack(">H", client.recv(2))[0]
	elif payload_length == 127:
		#with lock:
		payload_length = struct.unpack(">Q", client.recv(8))[0]
	#with lock:
	masks = client.recv(4)
	decoded = ""
	#with lock:
	data = client.recv(payload_length)
	for char in data:
		char ^= masks[len(decoded) % 4]
		decoded += chr(char)

	if callback:
		callback(decoded)
	return decoded



	


def thread_serve():
	s=Server()
	s.deinit()
	start_new_thread(echoserve, (False,))

def echoserve(blocking=True,port =9001):
	lock = allocate_lock()
	global sock
	global serving
	sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	sock.bind(("", port))
	sock.listen()
	sock.setblocking(blocking)
	global client
	print("waiting client at",port)
	serving=True
	while serving:
		client = None
		try:
			with lock:
				client, address = sock.accept()  
		except socket.error as e:
			if e.args[0]==11:
				sleep_ms(1000)
				continue
			else:
				print(e)
		print("client connected ",address)
		handshake(client)
		break
	print("End Thread Serving")
	#client, address = sock.accept()  
	client.setblocking(blocking)
	while serving:
		try:
			with lock:
				data = readMessage(client,None)
		except ValueError:
			sleep_ms(200)
			continue
		if data:
			with lock:
				sendMessage(client,"Echo "+data)
			if data=="quit":
				break
	print("End Thread Listening")



def stop():
	global sock
	global serving	
	global client
	serving=False
	sock.close()
	client.close()
	s=Server()

And the result error :

>>> execfile("wsServer.py")
>>> thread_serve()
>>> waiting client at 9001
client connected  ('192.168.4.2', 55233)
handshake Done
End Thread Serving
 
>>> ***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.
***ERROR*** A stack overflow in task Thread has been detected.

My code works without thread.
here client.html for testing, change ip according to your lopy ip :

<html>
<head>
  <title>Simple client</title>

  <script type="text/javascript">

    var ws;
    
    function init() {

      // Connect to Web Socket
      ws = new WebSocket("ws://192.168.4.1:9001/");

      // Set event handlers.
      ws.onopen = function() {
        output("onopen");
      };
      
      ws.onmessage = function(e) {
        // e.data contains received string.
        output("onmessage: " + e.data);
      };
      
      ws.onclose = function() {
        output("onclose");
      };

      ws.onerror = function(e) {
        output("onerror");
        console.log(e)
      };

    }
    
    function onSubmit() {
      var input = document.getElementById("input");
      // You can send message to the Web Socket using ws.send.
      ws.send(input.value);
      output("send: " + input.value);
      input.value = "";
      input.focus();
    }
    
    function onCloseClick() {
      ws.close();
    }
    
    function output(str) {
      var log = document.getElementById("log");
      var escaped = str.replace(/&/, "&amp;").replace(/</, "&lt;").
        replace(/>/, "&gt;").replace(/"/, "&quot;"); // "
      log.innerHTML = escaped + "<br>" + log.innerHTML;
    }

  </script>
</head>
<body onload="init();">
  <form onsubmit="onSubmit(); return false;">
    <input type="text" id="input">
    <input type="submit" value="Send">
    <button onclick="onCloseClick(); return false;">close</button>
  </form>
  <div id="log"></div>
</body>
</html>

sakis

Hi,

The best place for reporting potential bugs is https://github.com/pycom/pycom-micropython/issues. Can you please file an issue there?

Thank you

matamune

@sakis said in Thread WebSocketServer:

Hi,

The best place for reporting potential bugs is https://github.com/pycom/pycom-micropython/issues. Can you please file an issue there?

Thank you

Hi,
I have the same issue with a thread with an infinite loop (to display digit on a 7 segments).

Could it be related with the GC bug? (https://github.com/pycom/pycom-micropython/issues/39)

sakis

@matamune That's very likely. The best you can do is file a new ticket or if your are sure that it is the same issue add a comment on GitHub.

jobbyworld

Hello, i fllied a ticked :
https://github.com/pycom/pycom-micropython/issues/47

Testing with firmware 0.9.7 don't fix.
I don't use garbage collector, and my code use only one thread.
The error only occur after client connected in the message listen loop, and if i use the console.
But server still running and working after error.
I suspect interference with console or my own network because error occur only every 30 or 40 seconds

Hope that it will be fixed by next Release ;-)
Cheers

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