emit frames and let the server deal with them

handlers.ts

@@ -1,12 +1,8 @@
-import { createWriteStream } from "node:fs";
-
 import { Commands, CommandsByValue, ControlCommands } from "./datatypes.js";
 import { create_P2pRdy, SendStartVideo, SendUsrChk } from "./impl.js";
 import { Session } from "./server.js";
 
-let image_fds = [];
-let cur_image_index = 0;
-let size_so_far = 0;
+let curImage = null;
 
 export const notImpl = (_: Session, dv: DataView) => {
   const raw = dv.readU16();
@@ -56,7 +52,7 @@ export const createResponseForControlCommand = (session: Session, dv: DataView):
   }
 };
 
-const deal_with_data = (dv: DataView) => {
+const deal_with_data = (session: Session, dv: DataView) => {
   const pkt_len = dv.add(2).readU16();
   // data
   const JPEG_HEADER = [0xff, 0xd8, 0xff, 0xdb];
@@ -72,21 +68,15 @@ const deal_with_data = (dv: DataView) => {
   if (audio) {
     // TODO audio pkt
   } else {
-    if (is_new_image) {
-      size_so_far = 0;
-      if (cur_image_index > 0) {
-        image_fds[cur_image_index - 1].close();
-      }
-      const fname = `captures/${cur_image_index.toString().padStart(4, "0")}.jpg`;
-      let cur_image = createWriteStream(fname);
-      cur_image.cork();
-      image_fds[cur_image_index] = cur_image;
-      cur_image_index++;
-    }
-
     const data = dv.add(8).readByteArray(pkt_len - 4);
-    image_fds[cur_image_index - 1].write(Buffer.from(data.buffer));
-    size_so_far += pkt_len - 4;
+    if (is_new_image) {
+      if (curImage != null) {
+        session.frameEmitter.emit("frame", curImage);
+      }
+      curImage = Buffer.from(data.buffer);
+    } else {
+      curImage = Buffer.concat([curImage, Buffer.from(data.buffer)]);
+    }
   }
 };
 
@@ -112,7 +102,7 @@ export const handle_Drw = (session: Session, dv: DataView) => {
 
   const m_stream = dv.add(5).readU8(); // data = 1, control = 0
   if (m_stream == 1) {
-    deal_with_data(dv);
+    deal_with_data(session, dv);
   } else {
     const b = createResponseForControlCommand(session, dv);
     if (b != null) {

server.ts

@@ -1,8 +1,10 @@
 import dgram from "node:dgram";
+import { createWriteStream } from "node:fs";
 import { create_LanSearch } from "./func_replacements.js";
 import { Commands, CommandsByValue } from "./datatypes.js";
 import { handle_P2PAlive, handle_PunchPkt, handle_P2PRdy, handle_Drw, notImpl, noop } from "./handlers.js";
 import { hexdump } from "./hexdump.js";
+import EventEmitter from "node:events";
 
 export type sock = {};
 
@@ -40,6 +42,7 @@ const makeSession = (cb: msgCb, connCb: connCb, options?: opt): Session => {
   const session: Session = {
     outgoingCommandId: 0,
     ticket: [0, 0, 0, 0],
+    frameEmitter: new EventEmitter(),
     send: (msg: DataView) => {
       const raw = msg.readU16();
       const cmd = CommandsByValue[raw];
@@ -63,6 +66,7 @@ export type Session = {
   broadcast: (msg: DataView) => void;
   outgoingCommandId: number;
   ticket: number[];
+  frameEmitter: EventEmitter;
 };
 
 export type PacketHandler = (session: Session, dv: DataView) => void;
@@ -92,7 +96,7 @@ const Handlers: Record<keyof typeof Commands, PacketHandler> = {
   RlyHelloAck2: notImpl, // if len >1??
 };
 
-makeSession(
+const s = makeSession(
   (session, msg, _, options) => {
     const ab = new Uint8Array(msg).buffer;
     const dv = new DataView(ab);
@@ -110,5 +114,15 @@ makeSession(
       session.broadcast(buf);
     }, 1000);
   },
-  { debug: true, ansi: false },
+  { debug: false, ansi: false },
 );
+
+let cur_image_index = 0;
+s.frameEmitter.on("frame", (frame: Buffer) => {
+  const fname = `captures/${cur_image_index.toString().padStart(4, "0")}.jpg`;
+  let cur_image = createWriteStream(fname);
+  cur_image_index++;
+  cur_image.write(frame);
+  cur_image.close();
+  console.log("got an entire frame", frame.length);
+});