Added contructing a GPSPacket for sending

This patch adds the needed code to construct the raw output
string for sending a GPSPacket.

TODO: Need to incorporate speed, course, rng, position ambiguity ?
TODO: Need to add option to 'compress' the output location data.

aprsd/cmds/webchat.py

@@ -365,24 +365,12 @@ class SendMessageNamespace(Namespace):
         LOG.debug(f"Lat DDM {lat}")
         LOG.debug(f"Long DDM {long}")
 
-        local_datetime = datetime.datetime.now()
-        utc_offset_timedelta = datetime.datetime.utcnow() - local_datetime
-        result_utc_datetime = local_datetime + utc_offset_timedelta
-        time_zulu = result_utc_datetime.strftime("%d%H%M")
-
-        # now construct a beacon to send over the client connection
-        txt = (
-            f"{self._config['aprs']['login']}>APZ100,WIDE2-1"
-            f":@{time_zulu}z{lat}/{long}l APRSD WebChat Beacon"
-        )
-
-        LOG.debug(f"Sending {txt}")
         beacon = packets.GPSPacket(
             from_call=self._config["aprs"]["login"],
             to_call="APDW16",
-            raw=txt,
             latitude=lat,
             longitude=long,
+            comment="APRSD WebChat Beacon",
         )
         beacon.send_direct()
 

aprsd/packets/core.py

@@ -1,5 +1,6 @@
 import abc
 from dataclasses import asdict, dataclass, field
+import datetime
 import logging
 import re
 import time
@@ -220,7 +221,6 @@ class MessagePacket(PathPacket):
 @dataclass()
 class StatusPacket(PathPacket):
     status: str = None
-    timestamp: int = 0
     messagecapable: bool = False
     comment: str = None
 
@@ -235,15 +235,35 @@ class GPSPacket(PathPacket):
     altitude: float = 0.00
     rng: float = 0.00
     posambiguity: int = 0
-    timestamp: int = 0
     comment: str = None
-    symbol: str = None
-    symbol_table: str = None
+    symbol: str = field(default="l")
+    symbol_table: str = field(default="/")
     speed: float = 0.00
     course: int = 0
 
+    def _build_time_zulu(self):
+        """Build the timestamp in UTC/zulu."""
+        if self.timestamp:
+            local_dt = datetime.datetime.fromtimestamp(self.timestamp)
+        else:
+            local_dt = datetime.datetime.now()
+            self.timestamp = datetime.datetime.timestamp(local_dt)
+
+        utc_offset_timedelta = datetime.datetime.utcnow() - local_dt
+        result_utc_datetime = local_dt + utc_offset_timedelta
+        time_zulu = result_utc_datetime.strftime("%d%H%M")
+        return time_zulu
+
     def _build_raw(self):
-        raise NotImplementedError
+        time_zulu = self._build_time_zulu()
+
+        self.raw = (
+            f"{self.from_call}>{self.to_call},WIDE2-1:"
+            f"@{time_zulu}z{self.latitude}{self.symbol_table}"
+            f"{self.longitude}{self.symbol}"
+        )
+        if self.comment:
+            self.raw = f"{self.raw}{self.comment}"
 
 
 @dataclass()