fix(sharded): allow to target a specific socket ID in dynamic mode (#525)

Related: #524

Author: MartinKolarik

lib/sharded-adapter.ts

@@ -5,6 +5,10 @@ import debugModule from "debug";
 
 const debug = debugModule("socket.io-redis");
 
+function looksLikeASocketId(room: any) {
+  return typeof room === "string" && room.length === 20;
+}
+
 export interface ShardedRedisAdapterOptions {
   /**
    * The prefix for the Redis Pub/Sub channels.
@@ -128,7 +132,8 @@ class ShardedRedisAdapter extends ClusterAdapter {
       this.opts.subscriptionMode === "dynamic" &&
       message.type === MessageType.BROADCAST &&
       message.data.requestId === undefined &&
-      message.data.opts.rooms.length === 1;
+      message.data.opts.rooms.length === 1 &&
+      !looksLikeASocketId(message.data.opts.rooms[0]);
     if (useDynamicChannel) {
       return this.dynamicChannel(message.data.opts.rooms[0]);
     } else {

test/index.ts

@@ -110,6 +110,14 @@ export function testSuite(createAdapter: any) {
         servers[0].local.emit("test");
       });
 
+      it("broadcasts to a single client", (done) => {
+        clientSockets[0].on("test", shouldNotHappen(done));
+        clientSockets[1].on("test", () => done());
+        clientSockets[2].on("test", shouldNotHappen(done));
+
+        servers[0].to(serverSockets[1].id).emit("test");
+      });
+
       it("broadcasts with multiple acknowledgements", (done) => {
         clientSockets[0].on("test", (cb) => cb(1));
         clientSockets[1].on("test", (cb) => cb(2));