Initial commit: NestJS meshtastic bridge bot

2026-09-23 17:36:11 +00:00
commit 83e46b8f07
21 changed files with 6248 additions and 0 deletions
@@ -0,0 +1,89 @@
+import { create, fromBinary, toBinary } from '@bufbuild/protobuf';
+
+let proto: typeof import('@meshtastic/protobufs') | null = null;
+
+async function loadProto(): Promise<typeof import('@meshtastic/protobufs')> {
+  if (!proto) proto = await import('@meshtastic/protobufs');
+  return proto!;
+}
+
+export const BROADCAST_ADDR = 0xffffffff;
+// official portnums.proto: TEXT_MESSAGE_APP=1 (task spec draft said 3 — the enum value wins)
+export const PORT_TEXT_MESSAGE_APP = 1;
+
+const START1 = 0x94;
+const START2 = 0xc3;
+const MAX_LEN = 1024;
+
+export function extractFrames(buf: Uint8Array): {
+  packets: Uint8Array[];
+  rest: Uint8Array;
+} {
+  const packets: Uint8Array[] = [];
+  let i = 0;
+  for (;;) {
+    if (i >= buf.length) return { packets, rest: new Uint8Array(0) };
+    const isHeaderStart =
+      buf[i] === START1 && i + 1 < buf.length && buf[i + 1] === START2;
+    if (!isHeaderStart) {
+      // keep a trailing lone 0x94 — it may be the first byte of a split header
+      if (buf[i] === START1 && i + 1 >= buf.length)
+        return { packets, rest: buf.subarray(i) };
+      i++;
+      continue;
+    }
+    if (i + 4 > buf.length) return { packets, rest: buf.subarray(i) }; // partial header
+    const len = (buf[i + 2] << 8) | buf[i + 3];
+    if (len > MAX_LEN) {
+      i++; // bogus header — rescan from next byte
+      continue;
+    }
+    if (i + 4 + len > buf.length) return { packets, rest: buf.subarray(i) }; // partial payload
+    packets.push(buf.subarray(i + 4, i + 4 + len));
+    i += 4 + len;
+  }
+}
+
+export function frame(payload: Uint8Array): Uint8Array {
+  const out = new Uint8Array(4 + payload.length);
+  out[0] = START1;
+  out[1] = START2;
+  out[2] = (payload.length >> 8) & 0xff;
+  out[3] = payload.length & 0xff;
+  out.set(payload, 4);
+  return out;
+}
+
+export async function decodeFromRadio(
+  bytes: Uint8Array,
+): Promise<import('@meshtastic/protobufs').Mesh.FromRadio> {
+  const P = await loadProto();
+  return fromBinary(P.Mesh.FromRadioSchema, bytes);
+}
+
+export async function buildTextToRadio(
+  to: number,
+  text: string,
+): Promise<{ bytes: Uint8Array; id: number }> {
+  const P = await loadProto();
+  let id = Math.floor(Math.random() * 0x100000000) >>> 0;
+  if (id === 0) id = 1; // non-zero uint32
+  const meshPacket = create(P.Mesh.MeshPacketSchema, {
+    to,
+    id,
+    wantAck: true,
+    channel: 0,
+    payloadVariant: {
+      case: 'decoded',
+      value: {
+        portnum: P.Portnums.PortNum.TEXT_MESSAGE_APP,
+        payload: new TextEncoder().encode(text),
+        wantResponse: true,
+      },
+    },
+  });
+  const toRadio = create(P.Mesh.ToRadioSchema, {
+    payloadVariant: { case: 'packet', value: meshPacket },
+  });
+  return { bytes: frame(toBinary(P.Mesh.ToRadioSchema, toRadio)), id };
+}