Use zeroconf in service to discover devices

service/Pipfile

@@ -12,6 +12,7 @@ pyobjc-framework-cocoa = {version = "*", platform_system = "== 'Darwin'"}
 plyer = {version = "*", platform_system = "== 'Windows'"}
 jsonschema = "*"
 PyQt5 = "*"
+zeroconf = "*"
 
 [dev-packages]
 pyinstaller = "*"

service/service.py

@@ -7,6 +7,7 @@
 import time
 import uuid
 from PyQt5 import QtCore, QtGui, QtWidgets
+from zeroconf import Zeroconf, ServiceBrowser
 
 import common
 import driver_auto as driver
@@ -41,7 +42,7 @@ def __safe_get_status(getter_fn, fallback_value, name, duration_limit=0.25):
 # Previous return value is passed as last_status. On first call, None is passed.
 # counter goes up to args.send_rate-1, then back to 0. It can be used to do stuff every X iterations.
 # Before quitting, the function is called one more time with counter==-1. It sends out an "everything off" message in this case.
-def loopbody(args, counter, last_status):
+def loopbody(args, counter, last_status, enabled_devices):
     if counter >= 0:
         # Normal call
         fallback_status = last_status if last_status is not None else (False, False)
@@ -67,16 +68,27 @@ def loopbody(args, counter, last_status):
     # Send message if status changed, or every Xth round
     if status != last_status or (counter % args.send_rate)==0:
         common.log('Sending UDP message...')
-        for ip in args.ip:
-            sendudp(ip, args.port, msg)
+        for ip, port in enabled_devices:
+            sendudp(ip, port, msg)
 
     return status
 
 class App(QtWidgets.QApplication):
+    onDeviceAppeared = QtCore.pyqtSignal(str, list, int)
+    onDeviceDisappeared = QtCore.pyqtSignal(str)
+
     def __init__(self, args):
         QtWidgets.QApplication.__init__(self, sys.argv)
+        self.setQuitOnLastWindowClosed(False)
+
+        self.nearbyDevices = {}
+        self.onDeviceAppeared.connect(self.deviceAppeared)
+        self.onDeviceDisappeared.connect(self.deviceDisappeared)
 
         self.menu = QtWidgets.QMenu()
+        self.devicesMenu = self.menu.addMenu("Nearby devices")
+        self.devicesMenu.triggered.connect(self.toggleDevice)
+        self.menu.addAction("Add device manually", self.addDeviceManually)
         self.exitAction = self.menu.addAction("Exit", self.shutdown)
 
         style = self.style()
@@ -92,32 +104,81 @@ def __init__(self, args):
         self.last_status = None
         self.icounter = itertools.cycle(itertools.islice(itertools.count(start=0), self.args.send_rate))
 
-    def getIpAddress(self):
-        text, ok = QtWidgets.QInputDialog.getText(None, 'CheckMeet', 'Please provide IP address of device:')
-        if ok:
-            self.args.ip.append(text)
-        else:
-            driver.show_notification(APPNAME, 'Could not start service')
-            sys.exit(1) # can't use self.exit() here because the Qt event loop is not running yet
-
     def start(self):
-        if len(self.args.ip)==0:
-            self.getIpAddress()
-
         self.onTick()
         self.timer.start(self.args.query_interval*1000)
         self.trayIcon.show()
         driver.show_notification(APPNAME, 'Service started!✨')
 
+        if len(self.args.ip) > 0:
+            self.deviceAppeared(f"[Added on command line]", self.args.ip, self.args.port)
+
     def onTick(self):
         counter = next(self.icounter)
-        self.last_status = loopbody(self.args, counter, self.last_status)
+        self.last_status = loopbody(self.args, counter, self.last_status, self.getEnabledDevices())
 
     def shutdown(self):
-        loopbody(self.args, -1, self.last_status)
+        loopbody(self.args, -1, self.last_status, self.getEnabledDevices())
         common.log('Shutting down')
         self.exit()
 
+    def deviceAppeared(self, name, addresses, port):
+        print(f"deviceAppeared {name} {addresses} {port}")
+        if name in self.nearbyDevices:
+            print(f"Duplicate device {name}")
+            return
+
+        updatesEnabled = True
+        self.nearbyDevices[name] = {
+            'addresses': addresses,
+            'port': port,
+            'updatesEnabled': updatesEnabled,
+        }
+        a = self.devicesMenu.addAction(f"{name} {addresses}:{port}")
+        a.setCheckable(True)
+        a.setChecked(updatesEnabled)
+        self.nearbyDevices[name]['action'] = a
+
+    def deviceDisappeared(self, name):
+        print(f"deviceDisappeared {name}")
+        if name not in self.nearbyDevices:
+            print(f"Device not found {name}")
+            return
+
+        self.devicesMenu.removeAction(self.nearbyDevices[name]['action'])
+        del self.nearbyDevices[name]
+
+    def toggleDevice(self, action):
+        if action.isCheckable():
+            self.nearbyDevices[action.text()]["updatesEnabled"] = action.isChecked()
+
+    def getEnabledDevices(self):
+        result = []
+
+        for _, device in self.nearbyDevices.items():
+            if device['updatesEnabled']:
+                for ip in device['addresses']:
+                    result.append((ip, device['port']))
+
+        return result
+
+    def addDeviceManually(self):
+        text, ok = QtWidgets.QInputDialog.getText(None, 'CheckMeet', 'Please provide IP address of device:')
+        if ok:
+            self.deviceAppeared(f"[Manually added]", [text], self.args.port)
+
+    def add_service(self, zeroconf, serviceType, name):
+        info = zeroconf.get_service_info(serviceType, name)
+        self.onDeviceAppeared.emit(info.server, info.parsed_addresses(), info.port)
+
+    def remove_service(self, zeroconf, serviceType, name):
+        info = zeroconf.get_service_info(serviceType, name)
+        self.onDeviceDisappeared.emit(info.server)
+
+    def update_service(self, zeroconf, serviceType, name):
+        pass
+
+
 def main():
     parser = argparse.ArgumentParser(description='Service')
     parser.add_argument('--port', default=26999, type=int, help='Use UDP port')
@@ -127,9 +188,16 @@ def main():
     parser.add_argument('ip', nargs='*', help='Send UDP packets to these IP adresses')
     args = parser.parse_args()
 
+    zconf = Zeroconf()
     app = App(args)
-    app.start()
-    sys.exit(app.exec_())
+    ServiceBrowser(zconf, "_checkmeet._udp.local.", app)
+    try:
+        app.start()
+        exit_status = app.exec_()
+    finally:
+        zconf.close()
+
+    sys.exit(exit_status)
 
 if __name__ == '__main__':
     main()