Fix broken image when missing telemetry.

meshview/store.py

@@ -182,3 +182,12 @@ async def get_packets_seen(packet_id):
             .order_by(PacketSeen.import_time.desc())
         )
         return result.scalars()
+
+
+async def has_packets(node_id, portnum):
+    async with database.async_session() as session:
+        return bool(
+            (await session.execute(
+                    select(Packet.id).where(Packet.from_node_id == node_id).limit(1)
+            )).scalar()
+        )

meshview/templates/node.html

@@ -45,7 +45,9 @@
                             <dt>hw model</dt>
                             <dd>{{node.hw_model}}</dd>
                         </dl>
+                        {% if has_telemetry %}
                         <a href="/graph/power/{{node_id}}"><img src="/graph/power/{{node_id}}" height="200em" width="200em"/></a>
+                        {% endif %}
                     </div>
                     {% else %}
                     <div class="card-body">

meshview/web.py

@@ -237,6 +237,7 @@ async def packet_list(request):
         node = tg.create_task(store.get_node(node_id))
         trace = tg.create_task(build_trace(node_id))
         neighbors = tg.create_task(build_neighbors(node_id))
+        has_telemetry = tg.create_task(store.has_packets(node_id, PortNum.TELEMETRY_APP))
 
     packets = (Packet.from_model(p) for p in await raw_packets)
 
@@ -250,6 +251,7 @@ async def packet_list(request):
             packet_event="packet",
             trace=await trace,
             neighbors=await neighbors,
+            has_telemetry=await has_telemetry,
         ),
         content_type="text/html",
     )
@@ -264,6 +266,7 @@ async def uplinked_list(request):
         node = tg.create_task(store.get_node(node_id))
         trace = tg.create_task(build_trace(node_id))
         neighbors = tg.create_task(build_neighbors(node_id))
+        has_telemetry = tg.create_task(store.has_packets(node_id, PortNum.TELEMETRY_APP))
 
     packets = (Packet.from_model(p) for p in await raw_packets)
 
@@ -277,6 +280,7 @@ async def uplinked_list(request):
             packet_event="uplinked",
             trace=await trace,
             neighbors=await neighbors,
+            has_telemetry=await has_telemetry,
         ),
         content_type="text/html",
     )
@@ -437,6 +441,14 @@ async def graph_power(request):
         battery.append(payload.device_metrics.battery_level)
         voltage.append(payload.device_metrics.voltage)
 
+
+    if not date:
+        return web.Response(
+            status=404,
+            content_type="image/png",
+        )
+
+
     max_time = datetime.timedelta(days=4)
     newest = date[0]
     for i, d in enumerate(date):