feat: use redis for sessions

app/server.ts

@@ -4,11 +4,11 @@ import next from "next";
 import { Server } from "socket.io";
 import type { SocketServer } from "@/types";
 import { Field } from "@/utils/game";
+import * as redis from "@/utils/redis";
 
 const dev = process.env.NODE_ENV !== "production";
 const hostname = "localhost";
 const port = 3000;
-const sessions = new Set<string>();
 
 async function main() {
   const app = next({ dev, hostname, port });
@@ -25,7 +25,7 @@ async function main() {
   io.use(async (socket, next) => {
     const { sessionID } = socket.handshake.auth;
     if (sessionID) {
-      if (!sessions.has(sessionID)) {
+      if (await redis.isDeadSession(sessionID)) {
         return next(new Error("invalid session"));
       }
       socket.data.sessionID = sessionID;
@@ -37,7 +37,7 @@ async function main() {
   });
 
   io.on("connection", (socket) => {
-    sessions.add(socket.data.sessionID);
+    redis.startSession(socket.data.sessionID);
 
     socket.emit("session", {
       sessionID: socket.data.sessionID,

app/utils/redis.ts

@@ -1,24 +1,38 @@
 import { Redis } from "ioredis";
 import _ from "lodash";
 
-const key = "field:data";
+const fieldKey = "field:data";
+const sessionKey = "user:sessions";
 
-function getClient() {
-  return new Redis(process.env["REDIS_URL"]!, { family: 6 });
-}
+const redis = new Redis(process.env["REDIS_URL"]!, { family: 6 });
 
 export async function decodeData() {
-  const redis = getClient();
-  const value = await redis.get(key);
+  const value = await redis.get(fieldKey);
   if (typeof value !== "string" || !value) {
-    throw new Error(`unexpected data on key: ${key}`);
+    throw new Error(`unexpected data on key: ${fieldKey}`);
   }
   return Array.from(value, (char) => char.charCodeAt(0));
 }
 
 export async function encodeData(value: number[]) {
-  const redis = getClient();
   const binaryString = Buffer.from(value).toString("binary");
-  await redis.set(key, binaryString);
+  await redis.set(fieldKey, binaryString);
   return value;
 }
+
+export async function startSession(sessionId: string) {
+  return redis.sadd(sessionKey, sessionId);
+}
+
+export async function killSession(sessionId: string) {
+  return redis.srem(sessionKey, sessionId);
+}
+
+export async function isDeadSession(sessionId: string) {
+  const result = await redis.sismember(sessionKey, sessionId);
+  return !!result;
+}
+
+export async function resetSessions() {
+  return redis.del(sessionKey);
+}