support single-frame capture

capture_single.ts

@@ -0,0 +1,39 @@
+import fs from "node:fs";
+import { DevSerial } from "./impl.js";
+import { RemoteInfo } from "dgram";
+import { logger } from "./logger.js";
+import { startVideoStream } from "./session.js";
+import { discoverDevices } from "./discovery.js";
+import { Session } from "./session.js";
+import { Handlers, makeSession } from "./session.js";
+import { config } from "./settings.js";
+
+const sessions: Record<string, Session> = {};
+export const captureSingle = ({ discovery_ip, out_file }: { discovery_ip: string; out_file: string }) => {
+  let devEv = discoverDevices([discovery_ip]);
+
+  const startSession = (s: Session) => {
+    startVideoStream(s);
+    logger.info(`Camera ${s.devName} is now ready to stream`);
+  };
+
+  devEv.on("discover", (rinfo: RemoteInfo, dev: DevSerial) => {
+    if (dev.devId in sessions) {
+      logger.info(`Camera ${dev.devId} at ${rinfo.address} already discovered, ignoring`);
+      return;
+    }
+
+    logger.info(`Discovered camera ${dev.devId} at ${rinfo.address}`);
+    const s = makeSession(Handlers, dev, rinfo, startSession, 5000);
+    sessions[dev.devId] = s;
+    config.cameras[dev.devId] = { fix_packet_loss: false };
+
+    s.eventEmitter.on("frame", () => {
+      const assembled = Buffer.concat(s.curImage);
+      fs.writeFileSync(out_file, assembled);
+      logger.info(`Got frame. Exiting`);
+      devEv.emit("close");
+      s.close();
+    });
+  });
+};