feat: implement caching for user admission check

Author: Mohit-Davar

src/factories/message-handler-factory.ts

@@ -3,11 +3,21 @@ import { IncomingMessage, MessageType } from '../@types/messages'
 import { createSettings } from './settings-factory'
 import { EventMessageHandler } from '../handlers/event-message-handler'
 import { eventStrategyFactory } from './event-strategy-factory'
-import { IWebSocketAdapter } from '../@types/adapters'
+import { getCacheClient } from '../cache/client'
+import { ICacheAdapter, IWebSocketAdapter } from '../@types/adapters'
+import { RedisAdapter } from '../adapters/redis-adapter'
 import { slidingWindowRateLimiterFactory } from './rate-limiter-factory'
 import { SubscribeMessageHandler } from '../handlers/subscribe-message-handler'
 import { UnsubscribeMessageHandler } from '../handlers/unsubscribe-message-handler'
 
+let cacheAdapter: ICacheAdapter | undefined = undefined
+const getCache = (): ICacheAdapter => {
+  if (!cacheAdapter) {
+    cacheAdapter = new RedisAdapter(getCacheClient())
+  }
+  return cacheAdapter
+}
+
 export const messageHandlerFactory = (
   eventRepository: IEventRepository,
   userRepository: IUserRepository,
@@ -22,6 +32,7 @@ export const messageHandlerFactory = (
           userRepository,
           createSettings,
           slidingWindowRateLimiterFactory,
+          getCache(),
         )
       }
     case MessageType.REQ:

src/handlers/event-message-handler.ts

@@ -18,6 +18,7 @@ import { IEventStrategy, IMessageHandler } from '../@types/message-handlers'
 import { createCommandResult } from '../utils/messages'
 import { createLogger } from '../factories/logger-factory'
 import { Factory } from '../@types/base'
+import { ICacheAdapter } from '../@types/adapters'
 import { IncomingEventMessage } from '../@types/messages'
 import { IRateLimiter } from '../@types/utils'
 import { IWebSocketAdapter } from '../@types/adapters'
@@ -33,6 +34,7 @@ export class EventMessageHandler implements IMessageHandler {
     protected readonly userRepository: IUserRepository,
     private readonly settings: () => Settings,
     private readonly slidingWindowRateLimiter: Factory<IRateLimiter>,
+    private readonly cache: ICacheAdapter,
   ) {}
 
   public async handleMessage(message: IncomingEventMessage): Promise<void> {
@@ -313,17 +315,41 @@ export class EventMessageHandler implements IMessageHandler {
       return
     }
 
-    // const hasKey = await this.cache.hasKey(`${event.pubkey}:is-admitted`)
-    // TODO: use cache
+    const cacheKey = `${event.pubkey}:is-admitted`
+
+    try {
+      const cachedValue = await this.cache.getKey(cacheKey)
+      if (cachedValue === '1') {
+        debug('cache hit for %s admission: admitted', event.pubkey)
+        return
+      }
+      if (cachedValue === '0') {
+        debug('cache hit for %s admission: blocked', event.pubkey)
+        return 'blocked: pubkey not admitted'
+      }
+    } catch (error) {
+      debug('cache error for %s: %o', event.pubkey, error)
+    }
+
     const user = await this.userRepository.findByPubkey(event.pubkey)
     if (!user || !user.isAdmitted) {
+      this.cacheSet(cacheKey, '0', 60)
       return 'blocked: pubkey not admitted'
     }
 
     const minBalance = currentSettings.limits?.event?.pubkey?.minBalance ?? 0n
     if (minBalance > 0n && user.balance < minBalance) {
+      this.cacheSet(cacheKey, '0', 60)
       return 'blocked: insufficient balance'
     }
+
+    this.cacheSet(cacheKey, '1', 300)
+  }
+
+  private cacheSet(key: string, value: string, ttl: number): void {
+    this.cache.setKey(key, value)
+      .then(() => this.cache.setKeyExpiry(key, ttl))
+      .catch((error) => debug('unable to cache %s: %o', key, error))
   }
 
   protected addExpirationMetadata(event: Event): Event | ExpiringEvent {

test/unit/handlers/event-message-handler.spec.ts

@@ -88,7 +88,8 @@ describe('EventMessageHandler', () => {
         () => ({
           info: { relay_url: 'relay_url' },
         }) as any,
-        () => ({ hit: async () => false })
+        () => ({ hit: async () => false }),
+        { hasKey: async () => false, setKey: async () => true } as any,
       )
     })
 
@@ -262,7 +263,8 @@ describe('EventMessageHandler', () => {
         { hasActiveRequestToVanish: async () => false } as any,
         userRepository,
         () => settings,
-        () => ({ hit: async () => false })
+        () => ({ hit: async () => false }),
+        { hasKey: async () => false, setKey: async () => true } as any,
       )
     })
 
@@ -738,7 +740,8 @@ describe('EventMessageHandler', () => {
         { hasActiveRequestToVanish: async () => false } as any,
         userRepository,
         () => settings,
-        () => ({ hit: rateLimiterHitStub })
+        () => ({ hit: rateLimiterHitStub }),
+        { hasKey: async () => false, setKey: async () => true } as any,
       )
     })
 
@@ -1006,7 +1009,8 @@ describe('EventMessageHandler', () => {
         { hasActiveRequestToVanish: async () => false } as any,
         userRepository,
         () => settings,
-        () => ({ hit: async () => false })
+        () => ({ hit: async () => false }),
+        { hasKey: async () => false, getKey: async () => null, setKey: async () => true, setKeyExpiry: async () => undefined } as any,
       )
     })