bouncer: add caching feature back.

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

bouncer.js

@@ -6,7 +6,7 @@ const { validateEvent, nip19, matchFilters, mergeFilters, getFilterLimit } = req
 const auth = require("./auth.js");
 const nip42 = require("./nip42.js");
 
-let { relays, approved_publishers, blocked_publishers, log_about_relays, authorized_keys, private_keys, reconnect_time, wait_eose, pause_on_limit, max_eose_score, broadcast_ratelimit, upstream_ratelimit_expiration, max_client_subs, idle_sessions } = require(process.env.BOSTR_CONFIG_PATH || "./config");
+let { relays, approved_publishers, blocked_publishers, log_about_relays, authorized_keys, private_keys, reconnect_time, wait_eose, pause_on_limit, max_eose_score, broadcast_ratelimit, upstream_ratelimit_expiration, max_client_subs, idle_sessions, cache_relays } = require(process.env.BOSTR_CONFIG_PATH || "./config");
 
 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);
@@ -164,6 +164,7 @@ module.exports = (ws, req, onClose) => {
         ws.send(JSON.stringify(["CLOSED", origID, ""]));
         break;
       case "AUTH":
+        if (authorized) return;
         if (auth(authKey, data[1], ws, req)) {
           ws.pubkey = data[1].pubkey;
           console.log(process.pid, "---", ws.ip, "successfully authorized as", ws.pubkey, private_keys[ws.pubkey] ? "(admin)" : "(user)");
@@ -201,13 +202,15 @@ function newsess() {
   userRelays.set(id, new Set());
   csess.set(id, null);
   idleSess.add(id);
+  cache_relays?.forEach(_ => newConn(_, id));
   relays.forEach(_ => newConn(_, id));
 }
 
 // WS - Broadcast message to every existing sockets
-function bc(msg, id) {
+function bc(msg, id, toCacheOnly) {
   for (const sock of userRelays.get(id)) {
     if (sock.readyState !== 1) continue;
+    if (toCacheOnly && !sock.isCache) continue
 
     // skip the ratelimit after <config.upstream_ratelimit_expiration>
     if ((upstream_ratelimit_expiration) > (Date.now() - sock.ratelimit)) continue;
@@ -236,6 +239,7 @@ function newConn(addr, id, reconn_t = 0) {
     allowSynchronousEvents: true
   });
 
+  relay.isCache = cache_relays?.includes(addr);
   relay.ratelimit = 0;
   relay.on('open', _ => {
     if (!csess.has(id)) return relay.terminate();
@@ -267,9 +271,10 @@ function newConn(addr, id, reconn_t = 0) {
       case "EVENT": {
         if (data.length < 3 || typeof(data[1]) !== "string" || typeof(data[2]) !== "object") return;
         if (!client.subalias.has(data[1])) return;
+        if (!relay.isCache) bc(["EVENT", data[2]], id, true); // store to cache relay
         data[1] = client.subalias.get(data[1]);
         const filter = client.mergedFilters.get(data[1]);
-        if (client.pause_subs.has(data[1]) && (filter.since > data[2].created_at)) return;
+        if (client.pause_subs.has(data[1]) && (filter.since > data[2].created_at) && !relay.isCache) return;
 
         if (client.rejectKinds && client.rejectKinds.includes(data[2]?.id)) return;
 
@@ -293,6 +298,7 @@ function newConn(addr, id, reconn_t = 0) {
         if (client.events.get(data[1]).size >= limit) {
           // Once reached to <filter.limit>, send EOSE to client.
           client.send(JSON.stringify(["EOSE", data[1]]));
+
           if (!client.accurateMode && (client.saveMode || pause_on_limit)) {
             client.pause_subs.add(data[1]);
           } else {
@@ -306,6 +312,7 @@ function newConn(addr, id, reconn_t = 0) {
         data[1] = client.subalias.get(data[1]);
         if (!client.pendingEOSE.has(data[1])) return;
         client.pendingEOSE.set(data[1], client.pendingEOSE.get(data[1]) + 1);
+
         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 ${userRelays.get(id).size} connected relays.`);
 
         if (wait_eose && ((client.pendingEOSE.get(data[1]) < max_eose_score) || (client.pendingEOSE.get(data[1]) < userRelays.get(id).size))) return;

config.js.example

@@ -149,5 +149,16 @@ module.exports = {
     "wss://example2.com",
     // "wss://example3.com",
     // ...and so on
+  ],
+
+  // Cache relays - Store received events to cache relay(s) (Optional).
+  // Could improve the speed of event deliveries.
+  //
+  // Ensure that the cache relay does not has websocket ratelimit being set.
+  // CAUTION: - Cache relay is intensive in storing events. Watch for CPU usage.
+  //          - Only works best with only 1 cache relay.
+  //          - Things may not work properly if you configure more than just a single cache relays.
+  cache_relays: [
+    // "ws://localhost:3000"
   ]
 }