feat: add support for the ioredis package

Related: #2

Author: darrachequesne

lib/adapter.ts

@@ -1,14 +1,13 @@
 import type { PrivateSessionId, Session } from "socket.io-adapter";
 import { decode, encode } from "@msgpack/msgpack";
-import { commandOptions } from "redis";
 import {
   ClusterAdapter,
   ClusterAdapterOptions,
   ClusterMessage,
   MessageType,
 } from "./cluster-adapter";
 import debugModule from "debug";
-import { hasBinary } from "./util";
+import { hasBinary, XADD, XREAD } from "./util";
 
 const debug = debugModule("socket.io-redis-streams-adapter");
 
@@ -61,23 +60,15 @@ export function createAdapter(
   );
   let offset = "$";
   let polling = false;
+  let shouldClose = false;
 
   async function poll() {
     try {
-      let response = await redisClient.xRead(
-        commandOptions({
-          isolated: true,
-        }),
-        [
-          {
-            key: options.streamName,
-            id: offset,
-          },
-        ],
-        {
-          COUNT: options.readCount,
-          BLOCK: 5000,
-        }
+      let response = await XREAD(
+        redisClient,
+        options.streamName,
+        offset,
+        options.readCount
       );
 
       if (response) {
@@ -98,7 +89,7 @@ export function createAdapter(
       debug("something went wrong while consuming the stream: %s", e.message);
     }
 
-    if (namespaceToAdapters.size > 0 && redisClient.isOpen) {
+    if (namespaceToAdapters.size > 0 && !shouldClose) {
       poll();
     } else {
       polling = false;
@@ -111,6 +102,7 @@ export function createAdapter(
 
     if (!polling) {
       polling = true;
+      shouldClose = false;
       poll();
     }
 
@@ -119,6 +111,10 @@ export function createAdapter(
     adapter.close = () => {
       namespaceToAdapters.delete(nsp.name);
 
+      if (namespaceToAdapters.size === 0) {
+        shouldClose = true;
+      }
+
       defaultClose.call(adapter);
     };
 
@@ -141,17 +137,11 @@ class RedisStreamsAdapter extends ClusterAdapter {
   override doPublish(message: ClusterMessage) {
     debug("publishing %o", message);
 
-    return this.#redisClient.xAdd(
+    return XADD(
+      this.#redisClient,
       this.#opts.streamName,
-      "*",
       RedisStreamsAdapter.encode(message),
-      {
-        TRIM: {
-          strategy: "MAXLEN",
-          strategyModifier: "~",
-          threshold: this.#opts.maxLen,
-        },
-      }
+      this.#opts.maxLen
     );
   }
 

lib/util.ts

@@ -1,4 +1,5 @@
 import { randomBytes } from "crypto";
+import { commandOptions } from "redis";
 
 export function hasBinary(obj: any, toJSON?: boolean): boolean {
   if (!obj || typeof obj !== "object") {
@@ -34,3 +35,93 @@ export function hasBinary(obj: any, toJSON?: boolean): boolean {
 export function randomId() {
   return randomBytes(8).toString("hex");
 }
+
+/**
+ * Whether the client comes from the `redis` package
+ *
+ * @param redisClient
+ *
+ * @see https://github.com/redis/node-redis
+ */
+function isRedisV4Client(redisClient: any) {
+  return typeof redisClient.sSubscribe === "function";
+}
+
+/**
+ * @see https://redis.io/commands/xread/
+ */
+export function XREAD(
+  redisClient: any,
+  streamName: string,
+  offset: string,
+  readCount: number
+) {
+  if (isRedisV4Client(redisClient)) {
+    return redisClient.xRead(
+      commandOptions({
+        isolated: true,
+      }),
+      [
+        {
+          key: streamName,
+          id: offset,
+        },
+      ],
+      {
+        COUNT: readCount,
+        BLOCK: 5000,
+      }
+    );
+  } else {
+    return redisClient
+      .xread("BLOCK", 100, "COUNT", readCount, "STREAMS", streamName, offset)
+      .then((results) => {
+        if (results === null) {
+          return null;
+        }
+        return [
+          {
+            messages: results[0][1].map((result) => {
+              const id = result[0];
+              const inlineValues = result[1];
+              const message = {};
+              for (let i = 0; i < inlineValues.length; i += 2) {
+                message[inlineValues[i]] = inlineValues[i + 1];
+              }
+              return {
+                id,
+                message,
+              };
+            }),
+          },
+        ];
+      });
+  }
+}
+
+/**
+ * @see https://redis.io/commands/xadd/
+ */
+export function XADD(
+  redisClient: any,
+  streamName: string,
+  payload: any,
+  maxLenThreshold: number
+) {
+  if (isRedisV4Client(redisClient)) {
+    return redisClient.xAdd(streamName, "*", payload, {
+      TRIM: {
+        strategy: "MAXLEN",
+        strategyModifier: "~",
+        threshold: maxLenThreshold,
+      },
+    });
+  } else {
+    const args = [streamName, "MAXLEN", "~", maxLenThreshold, "*"];
+    Object.keys(payload).forEach((k) => {
+      args.push(k, payload[k]);
+    });
+
+    return redisClient.xadd.call(redisClient, args);
+  }
+}