feat: cookie for discovery

Author: vasco-santos

src/index.js

@@ -26,6 +26,14 @@ const defaultServerOptions = {
   gcInterval: 3e5
 }
 
+/**
+* Rendezvous point contains the connection to a rendezvous server, as well as,
+* the cookies per namespace that the client received.
+* @typedef {Object} RendezvousPoint
+* @property {Connection} connection
+* @property {Map<string, string>} cookies
+*/
+
 /**
  * Libp2p Rendezvous.
  * A lightweight mechanism for generalized peer discovery.
@@ -57,9 +65,15 @@ class Rendezvous {
     }
 
     /**
-     * @type {Map<string, Connection>}
+     * @type {Map<string, RendezvousPoint>}
      */
-    this._rendezvousConns = new Map()
+    this._rendezvousPoints = new Map()
+
+    /**
+    * Client cookies per namespace for own server
+    * @type {Map<string, string>}
+    */
+    this._cookiesSelf = new Map()
 
     this._server = undefined
 
@@ -120,12 +134,19 @@ class Rendezvous {
     }
 
     this._registrarId = undefined
+    this._rendezvousPoints.clear()
+    this._cookiesSelf.clear()
+
     log('stopped')
   }
 
+  /**
+   * Keep registrations updated on servers.
+   * @returns {void}
+   */
   _keepRegistrations () {
     const register = () => {
-      if (!this._rendezvousConns.size) {
+      if (!this._rendezvousPoints.size) {
         return
       }
 
@@ -152,7 +173,7 @@ class Rendezvous {
     const idB58Str = peerId.toB58String()
     log('connected', idB58Str)
 
-    this._rendezvousConns.set(idB58Str, conn)
+    this._rendezvousPoints.set(idB58Str, { connection: conn })
   }
 
   /**
@@ -164,7 +185,7 @@ class Rendezvous {
     const idB58Str = peerId.toB58String()
     log('disconnected', idB58Str)
 
-    this._rendezvousConns.delete(idB58Str)
+    this._rendezvousPoints.delete(idB58Str)
 
     if (this._server) {
       this._server.removePeerRegistrations(peerId)
@@ -196,7 +217,7 @@ class Rendezvous {
     }
 
     // Are there available rendezvous servers?
-    if (!this._rendezvousConns.size) {
+    if (!this._rendezvousPoints.size) {
       throw errCode(new Error('no rendezvous servers connected'), errCodes.NO_CONNECTED_RENDEZVOUS_SERVERS)
     }
 
@@ -214,8 +235,8 @@ class Rendezvous {
 
     const registerTasks = []
     const taskFn = async (id) => {
-      const conn = this._rendezvousConns.get(id)
-      const { stream } = await conn.newStream(PROTOCOL_MULTICODEC)
+      const { connection } = this._rendezvousPoints.get(id)
+      const { stream } = await connection.newStream(PROTOCOL_MULTICODEC)
 
       const [response] = await pipe(
         [message],
@@ -235,7 +256,7 @@ class Rendezvous {
       return recMessage.registerResponse.ttl
     }
 
-    for (const id of this._rendezvousConns.keys()) {
+    for (const id of this._rendezvousPoints.keys()) {
       registerTasks.push(taskFn(id))
     }
 
@@ -255,7 +276,7 @@ class Rendezvous {
     }
 
     // Are there available rendezvous servers?
-    if (!this._rendezvousConns.size) {
+    if (!this._rendezvousPoints.size) {
       throw errCode(new Error('no rendezvous servers connected'), errCodes.NO_CONNECTED_RENDEZVOUS_SERVERS)
     }
 
@@ -269,8 +290,8 @@ class Rendezvous {
 
     const unregisterTasks = []
     const taskFn = async (id) => {
-      const conn = this._rendezvousConns.get(id)
-      const { stream } = await conn.newStream(PROTOCOL_MULTICODEC)
+      const { connection } = this._rendezvousPoints.get(id)
+      const { stream } = await connection.newStream(PROTOCOL_MULTICODEC)
 
       await pipe(
         [message],
@@ -282,7 +303,7 @@ class Rendezvous {
       )
     }
 
-    for (const id of this._rendezvousConns.keys()) {
+    for (const id of this._rendezvousPoints.keys()) {
       unregisterTasks.push(taskFn(id))
     }
 
@@ -293,12 +314,11 @@ class Rendezvous {
    * Discover peers registered under a given namespace
    * @param {string} ns
    * @param {number} [limit]
-   * @param {Buffer} [cookie]
    * @returns {AsyncIterable<{ id: PeerId, multiaddrs: Array<Multiaddr>, ns: string, ttl: number }>}
    */
-  async * discover (ns, limit, cookie) {
+  async * discover (ns, limit) {
     // Are there available rendezvous servers?
-    if (!this._rendezvousConns.size) {
+    if (!this._rendezvousPoints.size) {
       throw errCode(new Error('no rendezvous servers connected'), errCodes.NO_CONNECTED_RENDEZVOUS_SERVERS)
     }
 
@@ -311,7 +331,9 @@ class Rendezvous {
 
     // Local search if Server
     if (this._server) {
-      const localRegistrations = this._server.getRegistrations(ns, limit)
+      const cookieSelf = this._cookiesSelf.get(ns)
+      const { cookie: cookieS, registrations: localRegistrations } = this._server.getRegistrations(ns, { limit, cookie: cookieSelf })
+
       for (const r of localRegistrations) {
         yield registrationTransformer(r)
 
@@ -320,21 +342,28 @@ class Rendezvous {
           return
         }
       }
-    }
 
-    const message = Message.encode({
-      type: MESSAGE_TYPE.DISCOVER,
-      discover: {
-        ns,
-        limit,
-        cookie
-      }
-    })
+      // Store cookie self
+      this._cookiesSelf.set(ns, cookieS)
+    }
 
-    for (const id of this._rendezvousConns.keys()) {
-      const conn = this._rendezvousConns.get(id)
-      const { stream } = await conn.newStream(PROTOCOL_MULTICODEC)
+    // Iterate over all rendezvous points
+    for (const [id, rp] of this._rendezvousPoints.entries()) {
+      const rpCookies = rp.cookies || new Map()
+
+      // Check if we have a cookie and encode discover message
+      const cookie = rpCookies.get(ns)
+      const message = Message.encode({
+        type: MESSAGE_TYPE.DISCOVER,
+        discover: {
+          ns,
+          limit,
+          cookie: cookie ? Buffer.from(cookie) : undefined
+        }
+      })
 
+      // Send discover message and wait for response
+      const { stream } = await rp.connection.newStream(PROTOCOL_MULTICODEC)
       const [response] = await pipe(
         [message],
         lp.encode(),
@@ -350,10 +379,18 @@ class Rendezvous {
         throw new Error('unexpected message received')
       }
 
+      // Iterate over registrations response
       for (const r of recMessage.discoverResponse.registrations) {
-        // track registrations and check if already provided
+        // track registrations
         yield registrationTransformer(r)
 
+        // Store cookie
+        rpCookies.set(ns, recMessage.discoverResponse.cookie.toString())
+        this._rendezvousPoints.set(id, {
+          connection: rp.connection,
+          cookies: rpCookies
+        })
+
         limit--
         if (limit === 0) {
           return