body: web joystick handle timeout

tools/joystick/web.py

@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 from flask import Flask
+import time
+import threading
 import cereal.messaging as messaging
 
 app = Flask(__name__)
@@ -29,8 +31,10 @@ setInterval(function(){
 def hello_world():
   return index
 
+last_send_time = time.time()
 @app.route("/control/<x>/<y>")
 def control(x, y):
+  global last_send_time
   x,y = float(x), float(y)
   x = max(-1, min(1, x))
   y = max(-1, min(1, y))
@@ -38,8 +42,21 @@ def control(x, y):
   dat.testJoystick.axes = [y,x]
   dat.testJoystick.buttons = [False]
   pm.send('testJoystick', dat)
+  last_send_time = time.time()
   return ""
 
+def handle_timeout():
+  while 1:
+    this_time = time.time()
+    if (last_send_time+0.5) < this_time:
+      print("timeout, no web in %.2f s" % (this_time-last_send_time))
+      dat = messaging.new_message('testJoystick')
+      dat.testJoystick.axes = [0,0]
+      dat.testJoystick.buttons = [False]
+      pm.send('testJoystick', dat)
+    time.sleep(0.1)
+
 if __name__ == '__main__':
+  threading.Thread(target=handle_timeout, daemon=True).start()
   app.run(host="0.0.0.0")