From eaec8d8691e58cff5a7fabc8fc81985e4af4f4f8 Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Tue, 17 Mar 2026 19:09:48 +0100
Subject: [PATCH] implemented send

---
 a_backend.py       |  4 +++-
 network_backend.py | 54 ++++++++++++++++++++++++++++++++++++++--------
 transceiver.py     |  4 ++++
 3 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/a_backend.py b/a_backend.py
index 6dbecf0..ac3eb76 100644
--- a/a_backend.py
+++ b/a_backend.py
@@ -1,4 +1,6 @@
 from abc import ABC
+from msg_container import MsgContainer
 
 class ABackend(ABC):
-	pass
\ No newline at end of file
+	def send(self, name: str, msg: MsgContainer):
+		pass
diff --git a/network_backend.py b/network_backend.py
index a36d9da..37d232d 100644
--- a/network_backend.py
+++ b/network_backend.py
@@ -13,12 +13,29 @@ from nmea.GSA import Gsa
 from nmea.GSV import Gsv
 from nmea.GGA import Gga
 from nmea.RMC import Rmc
+from threading import Thread
+from queue import Queue
 
 
 class NetworkBackend(ABackend):
 	def __init__(self, servers: list[dict]):
 		self.sel = None
-		self.sock_list = [{'name': s['name'], 'addr': (s['host'], s['port']), 'xcvr': None} for s in servers]
+		self.sock_list = [{'name': s['name'], 'addr': (s['host'], s['port']), 'xcvr': None, 'queue': Queue()} for s in servers]
+		self.thread = Thread(target=self.event_loop)
+		self.loop_enable = True
+
+	def send(self, name: str, msg: MsgContainer):
+		sock = self.find_by_name(name)
+		sock['queue'].put(msg)
+		if sock is not None:
+			self.sel.modify(sock['sock'], selectors.EVENT_READ + selectors.EVENT_WRITE, None)
+
+	def start(self):
+		self.thread.start()
+
+	def stop(self):
+		self.loop_enable = False
+		self.thread.join()
 
 	def create_xcvr(self, name: str) -> Transceiver:
 		obj = Transceiver(self, name)
@@ -67,19 +84,29 @@ class NetworkBackend(ABackend):
 		for sock in self.sock_list:
 			sock['sock'].close()
 
+	def on_send(self, name: str, data: bytes):
+		sock = self.find_by_name(name)
+		if sock is not None:
+			self.sel.modify(sock['sock'], selectors.EVENT_READ + selectors.EVENT_WRITE, data)
+
 	def event_loop(self):
 		try:
-			while True:
+			while self.loop_enable:
 				events = self.sel.select(timeout=100)
 				for key, mask in events:
 					descr = self.find_by_addr(key.fileobj.getpeername())
 					name = descr['name']
 					sock = self.find_by_name(name)
-					rx = sock['xcvr']
 					if mask & selectors.EVENT_READ:
 						timestamp = time.time()
 						data = key.fileobj.recv(16)
-						rx.on_recv(MsgContainer(name, timestamp, data))
+						sock['xcvr'].on_recv(MsgContainer(name, timestamp, data))
+					if mask & selectors.EVENT_WRITE:
+						data = sock['queue'].get()
+						key.fileobj.send(data)
+						print(f"Writing {key.data} to {sock['name']}")
+						if sock['queue'].empty():
+							self.sel.modify(sock['sock'], selectors.EVENT_READ, None)
 
 		except KeyboardInterrupt:
 			print("Caught keyboard interrupt, exiting")
@@ -92,6 +119,7 @@ if __name__ == "__main__":
 		{'name': "zed-x20p", 'host': "192.168.22.93", 'port': 8731}
 	]
 
+	transceiver = {}
 	# TCPIP multi source receiver
 	mc = NetworkBackend(server_list)
 	for grm in [" neo-f9p", "zed-x20p"]:
@@ -117,15 +145,15 @@ if __name__ == "__main__":
 		# Receiver-1.1 /
 
 		# Create transceiver
-		transceiver = mc.create_xcvr(grm)
+		transceiver[grm] = mc.create_xcvr(grm)
 
 		# Create NMEA-Packetizer
 		nmea_packetizer = NmeaPacketizer()
 		ubx_packetizer = UbxPacketizer()
 
 		# Register NMEA-Packetizer to transceiver
-		transceiver.register_recv(nmea_packetizer)
-		transceiver.register_recv(ubx_packetizer)
+		transceiver[grm].register_recv(nmea_packetizer)
+		transceiver[grm].register_recv(ubx_packetizer)
 
 		# Register Receiver to NMEA-Packetizer
 		for rx in nmea_rx_list:
@@ -139,8 +167,16 @@ if __name__ == "__main__":
 	# Connect all sources
 	mc.connect()
 
-	# receive and block
-	mc.event_loop()
+	# Start thread
+	mc.start()
+
+	for n in range(10):
+		for grm in [" neo-f9p", "zed-x20p"]:
+			transceiver[grm].send(b'Hallo')
+		time.sleep(1)
+
+	# Stop thread
+	mc.stop()
 
 	# code never reached
 	mc.disconnect()
diff --git a/transceiver.py b/transceiver.py
index 684d38a..dd63128 100644
--- a/transceiver.py
+++ b/transceiver.py
@@ -10,3 +10,7 @@ class Transceiver(MsgSource):
 
 	def on_recv(self, msg: MsgContainer):
 		self.call_sinks(msg)
+
+	def send(self, msg: MsgContainer):
+		self.backend.send(self.name, msg)
+