feat: user session management (#2056)

* user session management

* WIP

* cleanup

* license

* cleanup

* don't cache index

* rename current device property

* fix

apps/server/src/core/session/session-activity.service.ts

@@ -0,0 +1,36 @@
+import { Injectable } from '@nestjs/common';
+import { RedisService } from '@nestjs-labs/nestjs-ioredis';
+import type { Redis } from 'ioredis';
+import { UserSessionRepo } from '@docmost/db/repos/session/user-session.repo';
+import { UserRepo } from '@docmost/db/repos/user/user.repo';
+
+const THROTTLE_SECONDS = 15 * 60; // 15 minutes
+
+@Injectable()
+export class SessionActivityService {
+  private readonly redis: Redis;
+
+  constructor(
+    private readonly redisService: RedisService,
+    private readonly userSessionRepo: UserSessionRepo,
+    private readonly userRepo: UserRepo,
+  ) {
+    this.redis = this.redisService.getOrThrow();
+  }
+
+  trackActivity(sessionId: string, userId: string, workspaceId: string): void {
+    const key = `session:activity:${sessionId}`;
+
+    this.redis
+      .set(key, '1', 'EX', THROTTLE_SECONDS, 'NX')
+      .then((result) => {
+        if (result === null) return; // key already exists, throttled
+
+        this.userSessionRepo.updateLastActiveAt(sessionId).catch(() => {});
+        this.userRepo
+          .updateUser({ lastActiveAt: new Date() }, userId, workspaceId)
+          .catch(() => {});
+      })
+      .catch(() => {});
+  }
+}