spike: minimal N-API libdatachannel binding — WebRTC handshake proven

Phase 0 of GoLive rewrite (drop @dank074/node-datachannel 771MB): minimal N-API binding exposing PeerConnection/DataChannel/ICE/SDP, built against libdatachannel 0.24.0 (from node-datachannel _deps source). Verified: offer/answer/ICE/DataChannel roundtrip between two local peers (test-handshake.js). Key findings: - callbacks must be registered in ctor BEFORE createDataChannel - SDP with candidates comes from localDescription() at gathering Complete - answer auto-generates on setRemoteDescription(offer); do NOT call setLocalDescription() after or role=actpass breaks the peer
2026-08-11 14:23:31 +07:00
parent a53d7b71da
commit 2203dd5771
6 changed files with 481 additions and 0 deletions
@@ -0,0 +1,82 @@
+// Phase 0 spike: prove the minimal binding can do a full WebRTC handshake
+// (offer/answer + ICE + DataChannel) between two local PeerConnections.
+"use strict";
+const { PeerConnection } = require("./build/Release/datachannel_min.node");
+
+function log(...args) {
+  console.log("[spike]", ...args);
+}
+
+async function main() {
+  const pcA = new PeerConnection({ iceServers: [] });
+  const pcB = new PeerConnection({ iceServers: [] });
+
+  const stateLog = [];
+  pcA.onStateChange((s) => {
+    stateLog.push(`A:${s}`);
+    log("A state:", s);
+  });
+  pcB.onStateChange((s) => {
+    stateLog.push(`B:${s}`);
+    log("B state:", s);
+  });
+
+  // B waits for incoming DataChannel
+  const received = new Promise((resolve) => {
+    pcB.onDataChannel((dc) => {
+      log("B got incoming DataChannel");
+      dc.onOpen(() => log("B DataChannel open"));
+      dc.onMessage((msg) => {
+        log("B received message:", msg);
+        dc.send("pong from B");
+        resolve(msg);
+      });
+    });
+  });
+
+  // A creates an outgoing DataChannel
+  const dcA = pcA.createDataChannel("test");
+  dcA.onOpen(() => {
+    log("A DataChannel open — sending hello");
+    dcA.send("hello from A");
+  });
+  dcA.onMessage((msg) => {
+    log("A received reply:", msg);
+  });
+
+  // Offer/answer dance
+  log("A createOffer...");
+  const offer = await pcA.createOffer();
+  log("Offer SDP bytes:", offer.length);
+  log("B createAnswer...");
+  const answer = await pcB.createAnswer(offer);
+  log("Answer SDP bytes:", answer.length);
+  const setupMatch = answer.match(/a=setup:(\S+)/);
+  log("Answer setup role:", setupMatch ? setupMatch[1] : "NONE");
+  pcA.setRemoteDescription(answer, "answer");
+
+  // Wait for message roundtrip
+  const msg = await Promise.race([
+    received,
+    new Promise((_, rej) => setTimeout(() => rej(new Error("TIMEOUT waiting for datachannel message")), 15000)),
+  ]);
+
+  log("ROUNDTRIP OK — B got:", msg);
+  log("States:", stateLog.join(" | "));
+
+  const aState = pcA.state();
+  const bState = pcB.state();
+  log("Final states — A:", aState, "B:", bState);
+
+  pcA.close();
+  pcB.close();
+
+  if (msg !== "hello from A") throw new Error("wrong message");
+  if (aState !== "connected" && aState !== "disconnected") throw new Error("A not connected: " + aState);
+  log("SPIKE PASSED ✅");
+}
+
+main().catch((e) => {
+  console.error("SPIKE FAILED:", e.message);
+  process.exit(1);
+});