Include the node's public key in the contact QR code (#185)

* Include the node's public key in the contact QR code #184

The contact QR code and import URL never set user.public_key. Current
Meshtastic apps refuse to import a keyless contact. On 2.7.x firmware,
an older app's add_contact also overwrites the key the radio already
holds, so direct messages to that node fail.

Read the key from the node's latest stored NODEINFO_APP packet. Share
the contact only when a 32-byte key is known. Otherwise the node page
hides the QR buttons and says why. The QR API response now also
returns public_key.

Also drop the stray blank line that fails ruff format --check.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Do not share a contact when a node has reported more than one key #184

A forged NODEINFO uplinked over MQTT could otherwise become the newest
packet, and the shared contact would then replace the key a scanning
radio already trusts. The QR endpoint now reads every stored NODEINFO
from the node and refuses to share when their 32-byte keys disagree.
It reports that in public_key_conflict, and the node page says why.

Add an index on packet (from_node_id, portnum, import_time_us DESC) so
the lookup reads only the node's NODEINFO packets. Order with NULLS
LAST so PostgreSQL does not treat old rows without import_time_us as
newest. Carry is_licensed and is_unmessagable into the contact.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Skip NODEINFO rows with no payload when building the contact #184

packet.payload is nullable, and MeshPacket.FromString(None) raises
TypeError, so one such row made the QR endpoint answer 500.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

alembic/versions/4d2a7c9e1b30_add_packet_from_node_portnum_index.py

@@ -0,0 +1,37 @@
+"""Add packet index on from_node_id, portnum and import_time_us
+
+Revision ID: 4d2a7c9e1b30
+Revises: e8f2c4b6d9a1
+Create Date: 2026-10-26 00:00:00.000000
+
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "4d2a7c9e1b30"
+down_revision: str | None = "e8f2c4b6d9a1"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+INDEX_NAME = "idx_packet_from_node_portnum_time_us"
+
+
+def upgrade() -> None:
+    # Lets the node QR endpoint read a node's NODEINFO packets without scanning all its packets.
+    inspector = sa.inspect(op.get_bind())
+    if INDEX_NAME not in {index["name"] for index in inspector.get_indexes("packet")}:
+        op.create_index(
+            INDEX_NAME,
+            "packet",
+            ["from_node_id", "portnum", sa.text("import_time_us DESC")],
+            unique=False,
+        )
+
+
+def downgrade() -> None:
+    op.drop_index(INDEX_NAME, table_name="packet")

meshview/lang/en.json

@@ -246,7 +246,9 @@
         "share_contact_qr": "Share Contact QR",
         "copy_url": "Copy URL",
         "copied": "Copied!",
-        "scan_qr_to_add": "Scan this QR code to add this node as a contact on another device."
+        "scan_qr_to_add": "Scan this QR code to add this node as a contact on another device.",
+        "qr_no_public_key": "No public key heard from this node yet, so it cannot be shared as a contact.",
+        "qr_key_conflict": "This node has reported more than one public key, so it is not shared as a contact."
     },
     "packet": {
       "loading": "Loading packet information...",

meshview/lang/es.json

@@ -232,7 +232,9 @@
     "share_contact_qr": "Compartir contacto QR",
     "copy_url": "Copiar URL",
     "copied": "¡Copiado!",
-    "scan_qr_to_add": "Escanea este código QR para agregar este nodo como contacto en otro dispositivo."
+    "scan_qr_to_add": "Escanea este código QR para agregar este nodo como contacto en otro dispositivo.",
+    "qr_no_public_key": "Aún no se ha recibido la clave pública de este nodo, por lo que no se puede compartir como contacto.",
+    "qr_key_conflict": "Este nodo ha informado más de una clave pública, por lo que no se comparte como contacto."
   },
 
   "packet": {

meshview/lang/ru.json

@@ -227,7 +227,9 @@
         "share_contact_qr": "Поделиться QR контакта",
         "copy_url": "Копировать URL",
         "copied": "Скопировано!",
-        "scan_qr_to_add": "Отсканируйте этот QR-код, чтобы добавить эту ноду в качестве контакта на другом устройстве."
+        "scan_qr_to_add": "Отсканируйте этот QR-код, чтобы добавить эту ноду в качестве контакта на другом устройстве.",
+        "qr_no_public_key": "Открытый ключ этой ноды ещё не получен, поэтому её нельзя отправить как контакт.",
+        "qr_key_conflict": "Эта нода сообщила более одного открытого ключа, поэтому она не отправляется как контакт."
     },
     "packet": {
         "loading": "Загрузка информации о пакете...",

meshview/models.py

@@ -59,6 +59,12 @@ class Packet(Base):
         Index("idx_packet_to_node_id", "to_node_id"),
         Index("idx_packet_import_time_us", desc("import_time_us")),
         Index("idx_packet_from_node_time_us", "from_node_id", desc("import_time_us")),
+        Index(
+            "idx_packet_from_node_portnum_time_us",
+            "from_node_id",
+            "portnum",
+            desc("import_time_us"),
+        ),
     )
 
 

meshview/store.py

@@ -113,6 +113,17 @@ async def get_packets_from(node_id=None, portnum=None, since=None, limit=500):
         return result.scalars()
 
 
+async def get_nodeinfo_payloads(node_id):
+    """Return the payloads of every stored NODEINFO_APP packet from a node, newest first."""
+    async with database.async_session() as session:
+        result = await session.execute(
+            select(Packet.payload)
+            .where(Packet.from_node_id == node_id, Packet.portnum == PortNum.NODEINFO_APP)
+            .order_by(Packet.import_time_us.desc().nulls_last())
+        )
+        return result.scalars().all()
+
+
 async def get_packet(packet_id):
     async with database.async_session() as session:
         q = select(Packet).where(Packet.id == packet_id)

meshview/templates/node.html

@@ -173,6 +173,11 @@
     border-color: #48bb78;
     color: #fff;
 }
+.node-actions .qr-unavailable {
+    align-self: center;
+    color: #b0bec5;
+    font-size: 0.85rem;
+}
 .copy-success {
     color: #4ade80 !important;
     transition: opacity 0.3s;
@@ -315,6 +320,12 @@
         <button onclick="showQrCode()" id="showQrBtn">
             <span>🔳</span> <span data-translate-lang="show_qr_code">Show QR Code</span>
         </button>
+        <span class="qr-unavailable" id="qrUnavailable" style="display:none;" data-translate-lang="qr_no_public_key">
+            No public key heard from this node yet, so it cannot be shared as a contact.
+        </span>
+        <span class="qr-unavailable" id="qrKeyConflict" style="display:none;" data-translate-lang="qr_key_conflict">
+            This node has reported more than one public key, so it is not shared as a contact.
+        </span>
         <button onclick="openReachReport()" id="reachReportBtn">
             <span>📈</span> <span>Reliability</span>
         </button>
@@ -1811,8 +1822,16 @@ async function loadNodeQr() {
     try {
         const qrRes = await fetch(`/api/node/${fromNodeId}/qr`);
         const qrData = await qrRes.json();
-        if (qrRes.ok && qrData.meshtastic_url) {
-            currentMeshtasticUrl = qrData.meshtastic_url;
+        if (qrRes.ok) {
+            // No URL means no usable public key: none is known, or the node reported several.
+            currentMeshtasticUrl = qrData.meshtastic_url || "";
+            const canShare = Boolean(currentMeshtasticUrl);
+            const keyConflict = Boolean(qrData.public_key_conflict);
+            document.getElementById("copyUrlBtn").style.display = canShare ? "" : "none";
+            document.getElementById("showQrBtn").style.display = canShare ? "" : "none";
+            document.getElementById("qrUnavailable").style.display =
+                canShare || keyConflict ? "none" : "";
+            document.getElementById("qrKeyConflict").style.display = keyConflict ? "" : "none";
             actionsDiv.style.display = "flex";
         } else {
             actionsDiv.style.display = "none";

meshview/web_api/api.py

@@ -744,7 +744,6 @@ async def api_config(request):
             "map_bottom_right_lat": get_float(site, "map_bottom_right_lat", 36.0),
             "map_bottom_right_lon": get_float(site, "map_bottom_right_lon", -121.0),
             "map_interval": get_int(site, "map_interval", 3),
-
             "map_channel_colors": {
                 channel: color.strip()
                 for channel, color in CONFIG.get("map_channel_colors", {}).items()
@@ -1173,9 +1172,11 @@ async def api_node_qr(request):
         return web.json_response({"error": "Node not found"}, status=404)
 
     try:
+        from google.protobuf.message import DecodeError
+
         from meshtastic.protobuf.admin_pb2 import SharedContact
         from meshtastic.protobuf.config_pb2 import Config
-        from meshtastic.protobuf.mesh_pb2 import User
+        from meshtastic.protobuf.mesh_pb2 import MeshPacket, User
 
         user = User()
         user.id = f"!{node_id:08x}"
@@ -1200,18 +1201,52 @@ async def api_node_qr(request):
             except (AttributeError, TypeError):
                 pass
 
-        contact = SharedContact()
-        contact.node_num = node_id
-        contact.user.CopyFrom(user)
-        contact.manually_verified = False
+        # Meshview does not store public keys, so read them from the node's NODEINFO packets.
+        latest_nodeinfo = None
+        public_keys = set()
+        for payload in await store.get_nodeinfo_payloads(node_id):
+            if not payload:
+                continue
+            try:
+                mesh_packet = MeshPacket.FromString(payload)
+            except DecodeError:
+                continue
+            nodeinfo = decode_payload.decode_payload(
+                PortNum.NODEINFO_APP, mesh_packet.decoded.payload
+            )
+            if not isinstance(nodeinfo, User):
+                continue
+            if latest_nodeinfo is None:
+                latest_nodeinfo = nodeinfo
+            if len(nodeinfo.public_key) == 32:
+                public_keys.add(nodeinfo.public_key)
+
+        if latest_nodeinfo is not None:
+            if len(latest_nodeinfo.public_key) == 32:
+                user.public_key = latest_nodeinfo.public_key
+            user.is_licensed = latest_nodeinfo.is_licensed
+            if latest_nodeinfo.HasField("is_unmessagable"):
+                user.is_unmessagable = latest_nodeinfo.is_unmessagable
 
-        contact_bytes = contact.SerializeToString()
         import base64
 
-        contact_b64 = base64.b64encode(contact_bytes).decode("ascii")
-        contact_b64url = contact_b64.replace("+", "-").replace("/", "_").rstrip("=")
+        # A contact without a public key is refused by current Meshtastic apps and, on older
+        # firmware, erases the key the importing radio already has. Importing a contact also
+        # replaces a key the radio has pinned, so when the node's packets disagree on its key
+        # (one of them may be forged), share neither.
+        public_key_conflict = len(public_keys) > 1
+        meshtastic_url = None
+        if user.public_key and not public_key_conflict:
+            contact = SharedContact()
+            contact.node_num = node_id
+            contact.user.CopyFrom(user)
+            contact.manually_verified = False
 
-        meshtastic_url = f"https://meshtastic.org/v/#{contact_b64url}"
+            contact_bytes = contact.SerializeToString()
+            contact_b64 = base64.b64encode(contact_bytes).decode("ascii")
+            contact_b64url = contact_b64.replace("+", "-").replace("/", "_").rstrip("=")
+
+            meshtastic_url = f"https://meshtastic.org/v/#{contact_b64url}"
 
         return web.json_response(
             {
@@ -1219,6 +1254,10 @@ async def api_node_qr(request):
                 "long_name": node.long_name,
                 "short_name": node.short_name,
                 "role": node.role,
+                "public_key": (
+                    base64.b64encode(user.public_key).decode("ascii") if user.public_key else None
+                ),
+                "public_key_conflict": public_key_conflict,
                 "meshtastic_url": meshtastic_url,
             }
         )