nwcpush: calls wake a closed app. Kind 21059 wraps to a registered pubkey are watched; one big enough to be a call offer (an SDP) pushes 'call' at high urgency, a minute's TTL, naming the wrap, which the device fetches from GET /wrap/<id> (kept two minutes; a push can't carry it) and opens with its own key. ICE candidates and hang-ups are too small to wake anyone. A 'call' opt-out like the other reasons.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_013ZDf1cyCQLkfjftYhymZAg

1 files changed, 41 insertions, 4 deletions

diff --git a/nwcpush/server.js b/nwcpush/server.js
index 6d56f84..198757c 100644
--- a/nwcpush/server.js
+++ b/nwcpush/server.js
@@ -139,7 +139,8 @@ function resubscribeNotify() {
   const filters = [];
   // DMs / direct invites / zap receipts land p-tagged at the user
   // ...as do replies and mentions (kind 1 naming the user) and reactions (7)
-  if (ptags.length) filters.push({ kinds: [1059, 9735, 9737, 1, 7], '#p': ptags, since: Math.floor(Date.now() / 1000) });
+  // ...and calls ringing in (NIP-AC: ephemeral gift wraps, kind 21059)
+  if (ptags.length) filters.push({ kinds: [1059, 9735, 9737, 1, 7, CALL_WRAP], '#p': ptags, since: Math.floor(Date.now() / 1000) });
   // community chat: wraps authored by a channel's derived stream key
   if (authors.length) filters.push({ kinds: [1059], authors, since: Math.floor(Date.now() / 1000) });
   // one sub per filter — the pool API takes a single filter object
@@ -152,7 +153,27 @@ function resubscribeNotify() {
 // DMs are throttled barely at all now: the device drops the ones it decides
 // are noise (a stranger, or our own sent-copy), and a server-side cooldown
 // would let a discarded push swallow the friend's message that followed it.
-const COOLDOWN = { payment: 10_000, zap: 10_000, dm: 1_000, chat: 90_000, mention: 5_000, reaction: 30_000 };
+const COOLDOWN = { payment: 10_000, zap: 10_000, dm: 1_000, chat: 90_000, mention: 5_000, reaction: 30_000, call: 3_000 };
+
+// Calls (NIP-AC). Every setup message of a call is a kind 21059 wrap to the
+// person — the offer that rings them, then a stream of ICE candidates and
+// the hang-up — and none can be read here. An offer carries a whole SDP, so
+// its wrap is several kilobytes; candidates and hang-ups are a few hundred
+// bytes. Only a wrap big enough to be an offer wakes the device (a push the
+// device then shows nothing for counts against the site in Chrome), and a
+// whole offer is too big for a push (~4 KB), so the push says which wrap and
+// the device fetches it from here (GET /wrap/<id>) and opens it itself.
+const CALL_WRAP = 21059;
+const CALL_OFFER_MIN = 2000; // wrap content length: an offer's is ~4-10 KB, a candidate's ~1 KB
+const CALL_KEEP_MS = 120_000;
+const callWraps = new Map(); // wrap id -> { ev, at }
+function keepCallWrap(ev) {
+  callWraps.set(ev.id, { ev, at: Date.now() });
+  if (callWraps.size > 500) {
+    const cut = Date.now() - CALL_KEEP_MS;
+    for (const [k, v] of callWraps) if (v.at < cut || callWraps.size > 500) callWraps.delete(k);
+  }
+}
 const lastPush = new Map(); // endpointId:reason -> ts
 const seenNotifyEvents = new Map(); // event id -> ts
 function onNotifyEvent(ev) {
@@ -189,6 +210,14 @@ function onNotifyEvent(ev) {
     }
     return;
   }
+  if (ev.kind === CALL_WRAP) {
+    if (!p || String(ev.content || '').length < CALL_OFFER_MIN) return;
+    keepCallWrap(ev);
+    for (const [id, r] of Object.entries(notifyRegs)) {
+      if ((r.ptags || []).includes(p)) pushNotify(id, r, 'call', { wrapId: ev.id }).catch(() => {});
+    }
+    return;
+  }
   const zap = ev.kind === 9735 || ev.kind === 9737;
   const reason = zap ? 'payment'
     : p && notifyPtags().includes(p) ? 'dm' : 'chat';
@@ -224,7 +253,8 @@ async function pushNotify(id, r, reason, extra) {
   // dozes, so it got them all). Money and people talking to you go 'high'
   // and keep for a day; reactions and community chatter can wait.
   const loud = ['payment', 'zap', 'dm', 'mention'].includes(reason);
-  const opts = loud ? { TTL: 86400, urgency: 'high' } : { TTL: 3600, urgency: 'normal' };
+  // a call rings now or not at all: a minute, then it's a missed call
+  const opts = reason === 'call' ? { TTL: 60, urgency: 'high' } : loud ? { TTL: 86400, urgency: 'high' } : { TTL: 3600, urgency: 'normal' };
   try {
     try {
       await deliver(r.sub, payload, opts);
@@ -384,6 +414,13 @@ const server = Bun.serve({
 
     // The browser needs this to create a PushSubscription.
     if (url.pathname === '/vapid') return json({ publicKey: CFG.vapid.publicKey });
+    // a call's offer wrap, for the device a push woke (see CALL_WRAP above):
+    // still encrypted to them, as every relay that carried it saw it
+    const wm = /^\/wrap\/([0-9a-f]{64})$/.exec(url.pathname);
+    if (wm && req.method === 'GET') {
+      const w = callWraps.get(wm[1]);
+      return w && Date.now() - w.at < CALL_KEEP_MS ? json(w.ev) : json({ error: 'gone' }, 404);
+    }
 
     // Publish-back for the auto-answering service worker: it cannot hold a
     // relay socket, so it hands us its (encrypted, service-key-signed) reply.
@@ -463,7 +500,7 @@ const server = Bun.serve({
         const id = Bun.hash(sub_.endpoint).toString(36);
         // per-category opt-outs; absent means everything on (older clients)
         const reasons = {};
-        for (const k of ['payment', 'zap', 'dm', 'chat', 'mention', 'reaction']) {
+        for (const k of ['payment', 'zap', 'dm', 'chat', 'mention', 'reaction', 'call']) {
           if (typeof body.notify.reasons?.[k] === 'boolean') reasons[k] = body.notify.reasons[k];
         }
         notifyRegs[id] = {