feat: Orphan Session

Add feature to keep and reuse an session to cut some loads off &
somewhat improve bouncing performance.

Signed-off-by: Yonle <yonle@lecturify.net>

bouncer.js

@@ -3,11 +3,12 @@ const { verifySignature, validateEvent, nip19 } = require("nostr-tools");
 const auth = require("./auth.js");
 const nip42 = require("./nip42.js");
 
-let { relays, approved_publishers, log_about_relays, authorized_keys, private_keys, reconnect_time, wait_eose, pause_on_limit, eose_timeout, max_eose_score, cache_relays } = require("./config");
+let { relays, approved_publishers, log_about_relays, authorized_keys, private_keys, reconnect_time, wait_eose, pause_on_limit, eose_timeout, max_eose_score, cache_relays, max_orphan_sess } = require("./config");
 
 const socks = new Set();
 const csess = new Map();
 
+log_about_relays = process.env.LOG_ABOUT_RELAYS || log_about_relays;
 authorized_keys = authorized_keys?.map(i => i.startsWith("npub") ? nip19.decode(i).data : i);
 approved_publishers = approved_publishers?.map(i => i.startsWith("npub") ? nip19.decode(i).data : i);
 
@@ -20,8 +21,9 @@ cache_relays = cache_relays?.map(i => i.endsWith("/") ? i : i + "/");
 module.exports = (ws, req) => {
   let authKey = null;
   let authorized = true;
+  let orphan = getOrphanSess(); // if available
 
-  ws.id = process.pid + Math.floor(Math.random() * 1000) + "_" + csess.size;
+  ws.id = orphan || (process.pid + Math.floor(Math.random() * 1000) + "_" + csess.size);
   ws.subs = new Map(); // contains filter submitted by clients. per subID
   ws.pause_subs = new Set(); // pause subscriptions from receiving events after reached over <filter.limit> until all relays send EOSE. per subID
   ws.events = new Map(); // only to prevent the retransmit of the same event. per subID
@@ -100,7 +102,9 @@ module.exports = (ws, req) => {
           ws.pubkey = data[1].pubkey;
           console.log(process.pid, "---", ws.id, "successfully authorized as", ws.pubkey, private_keys[ws.pubkey] ? "(admin)" : "(user)");
           if (authorized) return;
-          newsess(ws.id);
+          // if orphan, ignore
+          csess.set(ws.id, ws);
+          if (!orphan) newsess(ws.id);
           authorized = true;
         }
         break;
@@ -113,23 +117,26 @@ module.exports = (ws, req) => {
   ws.on('error', console.error);
   ws.on('close', _ => {
     console.log(process.pid, "---", "Sock", ws.id, "has disconnected.");
-    csess.delete(ws.id);
+    csess.set(ws.id, null); // set as orphan.
 
     for (i of ws.EOSETimeout) {
       clearTimeout(i[1]);
     }
 
     if (!authorized) return;
-    terminate_subs(ws.id);
 
     for (i of ws.reconnectTimeout) {
       clearTimeout(i);
       // Let the garbage collector do the thing. No need to add ws.reconnectTimeout.delete(i);
     }
+
+    onClientDisconnect();
   });
 
-  csess.set(ws.id, ws);
+  if (authorized) {
-  if (authorized) newsess(ws.id);
+    csess.set(ws.id, ws);
+    if (!orphan) newsess(ws.id);
+  }
 }
 
 // CL - Set up EOSE timeout
@@ -162,8 +169,8 @@ function cancel_EOSETimeout(id, subid) {
 
 // WS - New session for client $id
 function newsess(id) {
-  relays.forEach(_ => newConn(_, id));
   cache_relays?.forEach(_ => newConn(_, id));
+  relays.forEach(_ => newConn(_, id));
 }
 
 // WS - Broadcast message to every existing sockets
@@ -191,7 +198,7 @@ function bc(msg, id) {
 }
 
 // WS - Terminate all existing sockets that were for <id>
-function terminate_subs(id) {
+function terminate_sess(id) {
   for (sock of socks) {
     if (sock.id !== id) continue;
     sock.terminate();
@@ -199,6 +206,43 @@ function terminate_subs(id) {
   }
 }
 
+function onClientDisconnect() {
+  const orphanSessNum = howManyOrphanSess();
+  const max = max_orphan_sess || 0;
+  if (orphanSessNum > max) {
+    if (log_about_relays) console.log(process.pid, `There are ${orphanSessNum} of orphan session. I will clear ${orphanSessNum - max} of orphan sessions.`);
+    clearOrphanSess(orphanSessNum - max);
+  }
+}
+
+function getOrphanSess() {
+  for (sess of csess) {
+    if (sess[1] !== null) continue;
+    return sess[0];
+    break;
+  }
+}
+
+function howManyOrphanSess() {
+  let howMany = 0;
+  for (sess of csess) {
+    if (sess[1] !== null) continue;
+    howMany++
+  }
+
+  return howMany;
+}
+
+function clearOrphanSess(l) {
+  let cn = 0;
+  for (sess of csess) {
+    if (cn > l) break;
+    if (sess[1] !== null) continue;
+    terminate_sess(sess[0]);
+    cn++;
+  }
+}
+
 // WS - Sessions
 function newConn(addr, id) {
   if (!csess.has(id)) return;
@@ -213,8 +257,9 @@ function newConn(addr, id) {
   relay.on('open', _ => {
     if (!csess.has(id)) return relay.terminate();
     socks.add(relay); // Add this socket session to [socks]
-    if (process.env.LOG_ABOUT_RELAYS || log_about_relays) console.log(process.pid, "---", `[${id}] [${socks.size}/${relays.length*csess.size}]`, relay.url, "is connected");
+    if (log_about_relays) console.log(process.pid, "---", `[${id}] [${socks.size}/${relays.length*csess.size}] ${relay.url} is connected ${!client ? "(orphan)" : ""}`);
 
+    if (!client) return; // is orphan, do nothing.
     for (i of client.my_events) {
       relay.send(JSON.stringify(["EVENT", i]));
     }
@@ -225,6 +270,7 @@ function newConn(addr, id) {
   });
 
   relay.on('message', data => {
+    if (!client) return;
     try {
       data = JSON.parse(data);
     } catch (error) {
@@ -275,7 +321,7 @@ function newConn(addr, id) {
       case "EOSE":
         if (!client.pendingEOSE.has(data[1])) return;
         client.pendingEOSE.set(data[1], client.pendingEOSE.get(data[1]) + 1);
-        if (process.env.LOG_ABOUT_RELAYS || log_about_relays) console.log(process.pid, "---", `[${id}]`, `got EOSE from ${relay.url} for ${data[1]}. There are ${client.pendingEOSE.get(data[1])} EOSE received out of ${Array.from(socks).filter(sock => sock.id === id).length} connected relays.`);
+        if (log_about_relays) console.log(process.pid, "---", `[${id}]`, `got EOSE from ${relay.url} for ${data[1]}. There are ${client.pendingEOSE.get(data[1])} EOSE received out of ${Array.from(socks).filter(sock => sock.id === id).length} connected relays.`);
 
         if (!cache_relays?.includes(relay.url)) {
           if (wait_eose && ((client.pendingEOSE.get(data[1]) < max_eose_score) || (client.pendingEOSE.get(data[1]) < Array.from(socks).filter(sock => sock.id === id).length))) return;
@@ -305,18 +351,18 @@ function newConn(addr, id) {
   });
 
   relay.on('error', _ => {
-    if (process.env.LOG_ABOUT_RELAYS || log_about_relays) console.error(process.pid, "-!-", `[${id}]`, relay.url, _.toString())
+    if (log_about_relays) console.error(process.pid, "-!-", `[${id}]`, relay.url, _.toString())
   });
 
   relay.on('close', _ => {
     socks.delete(relay) // Remove this socket session from [socks] list
-    if (process.env.LOG_ABOUT_RELAYS || log_about_relays) console.log(process.pid, "-!-", `[${id}] [${socks.size}/${relays.length*csess.size}]`, "Disconnected from", relay.url);
+    if (log_about_relays) console.log(process.pid, "-!-", `[${id}] [${socks.size}/${relays.length*csess.size}]`, "Disconnected from", relay.url);
 
     if (!csess.has(id)) return;
     const reconnectTimeout = setTimeout(_ => {
       newConn(addr, id);
-      client.reconnectTimeout.delete(reconnectTimeout);
+      client?.reconnectTimeout.delete(reconnectTimeout);
     }, reconnect_time || 5000); // As a bouncer server, We need to reconnect.
-    client.reconnectTimeout.add(reconnectTimeout);
+    client?.reconnectTimeout.add(reconnectTimeout);
   });
 }

config.js.example

@@ -16,6 +16,11 @@ module.exports = {
   // Time before reconnect to relays in milliseconds.
   reconnect_time: 5000,
 
+  // Maximum amount of orphan sessions.
+  // Setting to 0 disables orphan session function.
+  // PRIVACY WARNING: Enabling this may could leak some events that people were not supposed to receive (Eg. PM)
+  max_orphan_sess: 0,
+
   // Wait for every connected relays send EOSE.
   // Could improve accuracy on received events.
   //