feat: add NIP-62 vanish event support

Author: vikashsiwach

src/@types/repositories.ts

@@ -17,6 +17,8 @@ export interface IEventRepository {
   upsert(event: Event): Promise<number>
   findByFilters(filters: SubscriptionFilter[]): IQueryResult<DBEvent[]>
   deleteByPubkeyAndIds(pubkey: Pubkey, ids: EventId[]): Promise<number>
+  deleteByPubkeyExceptKinds(pubkey: Pubkey, excludedKinds: number[]): Promise<number>
+  hasActiveRequestToVanish(pubkey: Pubkey): Promise<boolean>
 }
 
 export interface IInvoiceRepository {

src/constants/base.ts

@@ -7,6 +7,7 @@ export enum EventKinds {
   DELETE = 5,
   REPOST = 6,
   REACTION = 7,
+  REQUEST_TO_VANISH = 62,
   // Channels
   CHANNEL_CREATION = 40,
   CHANNEL_METADATA = 41,
@@ -36,12 +37,15 @@ export enum EventKinds {
 export enum EventTags {
   Event = 'e',
   Pubkey = 'p',
+  Relay = 'r',
   //  Multicast = 'm',
   Deduplication = 'd',
   Expiration = 'expiration',
   Invoice = 'bolt11',
 }
 
+export const ALL_RELAYS = 'ALL_RELAYS'
+
 export enum PaymentsProcessors {
   LNURL = 'lnurl',
   ZEBEDEE = 'zebedee',

src/factories/event-strategy-factory.ts

@@ -1,4 +1,4 @@
-import { isDeleteEvent, isEphemeralEvent, isParameterizedReplaceableEvent, isReplaceableEvent } from '../utils/event'
+import { isDeleteEvent, isEphemeralEvent, isParameterizedReplaceableEvent, isReplaceableEvent, isRequestToVanishEvent } from '../utils/event'
 import { DefaultEventStrategy } from '../handlers/event-strategies/default-event-strategy'
 import { DeleteEventStrategy } from '../handlers/event-strategies/delete-event-strategy'
 import { EphemeralEventStrategy } from '../handlers/event-strategies/ephemeral-event-strategy'
@@ -9,12 +9,15 @@ import { IEventStrategy } from '../@types/message-handlers'
 import { IWebSocketAdapter } from '../@types/adapters'
 import { ParameterizedReplaceableEventStrategy } from '../handlers/event-strategies/parameterized-replaceable-event-strategy'
 import { ReplaceableEventStrategy } from '../handlers/event-strategies/replaceable-event-strategy'
+import { VanishEventStrategy } from '../handlers/event-strategies/vanish-event-strategy'
 
 export const eventStrategyFactory = (
   eventRepository: IEventRepository,
 ): Factory<IEventStrategy<Event, Promise<void>>, [Event, IWebSocketAdapter]> =>
   ([event, adapter]: [Event, IWebSocketAdapter]) => {
-    if (isReplaceableEvent(event)) {
+    if (isRequestToVanishEvent(event)) {
+      return new VanishEventStrategy(adapter, eventRepository)
+    } else if (isReplaceableEvent(event)) {
       return new ReplaceableEventStrategy(adapter, eventRepository)
     } else if (isEphemeralEvent(event)) {
       return new EphemeralEventStrategy(adapter)

src/factories/message-handler-factory.ts

@@ -18,6 +18,7 @@ export const messageHandlerFactory = (
         return new EventMessageHandler(
           adapter,
           eventStrategyFactory(eventRepository),
+          eventRepository,
           userRepository,
           createSettings,
           slidingWindowRateLimiterFactory,

src/handlers/event-message-handler.ts

@@ -1,15 +1,26 @@
-import { Event, ExpiringEvent  } from '../@types/event'
+import { ContextMetadataKey, EventExpirationTimeMetadataKey } from '../constants/base'
+import { Event, ExpiringEvent } from '../@types/event'
 import { EventRateLimit, FeeSchedule, Settings } from '../@types/settings'
-import { getEventExpiration, getEventProofOfWork, getPubkeyProofOfWork, getPublicKey, getRelayPrivateKey, isEventIdValid, isEventKindOrRangeMatch, isEventSignatureValid, isExpiredEvent } from '../utils/event'
+import {
+  getEventExpiration,
+  getEventProofOfWork,
+  getPubkeyProofOfWork,
+  getPublicKey,
+  getRelayPrivateKey,
+  isEventIdValid,
+  isEventKindOrRangeMatch,
+  isEventSignatureValid,
+  isExpiredEvent,
+  isRequestToVanishEvent,
+  isValidRequestToVanishEvent,
+} from '../utils/event'
+import { IEventRepository, IUserRepository } from '../@types/repositories'
 import { IEventStrategy, IMessageHandler } from '../@types/message-handlers'
-import { ContextMetadataKey } from '../constants/base'
 import { createCommandResult } from '../utils/messages'
 import { createLogger } from '../factories/logger-factory'
-import { EventExpirationTimeMetadataKey } from '../constants/base'
 import { Factory } from '../@types/base'
 import { IncomingEventMessage } from '../@types/messages'
 import { IRateLimiter } from '../@types/utils'
-import { IUserRepository } from '../@types/repositories'
 import { IWebSocketAdapter } from '../@types/adapters'
 import { WebSocketAdapterEvent } from '../constants/adapter'
 
@@ -19,6 +30,7 @@ export class EventMessageHandler implements IMessageHandler {
   public constructor(
     protected readonly webSocket: IWebSocketAdapter,
     protected readonly strategyFactory: Factory<IEventStrategy<Event, Promise<void>>, [Event, IWebSocketAdapter]>,
+    protected readonly eventRepository: IEventRepository,
     protected readonly userRepository: IUserRepository,
     private readonly settings: () => Settings,
     private readonly slidingWindowRateLimiter: Factory<IRateLimiter>,
@@ -57,6 +69,13 @@ export class EventMessageHandler implements IMessageHandler {
       return
     }
 
+    reason = await this.isBlockedByRequestToVanish(event)
+    if (reason) {
+      debug('event %s rejected: %s', event.id, reason)
+      this.webSocket.emit(WebSocketAdapterEvent.Message, createCommandResult(event.id, false, reason))
+      return
+    }
+
     reason = await this.isUserAdmitted(event)
     if (reason) {
       debug('event %s rejected: %s', event.id, reason)
@@ -190,6 +209,26 @@ export class EventMessageHandler implements IMessageHandler {
     if (!await isEventSignatureValid(event)) {
       return 'invalid: event signature verification failed'
     }
+
+    if (isRequestToVanishEvent(event) && !isValidRequestToVanishEvent(event, this.settings().info.relay_url)) {
+      return 'invalid: request to vanish relay tag invalid'
+    }
+  }
+
+  protected async isBlockedByRequestToVanish(event: Event): Promise<string | undefined> {
+    if (isRequestToVanishEvent(event)) {
+      return
+    }
+
+    const relayPubkey = this.getRelayPublicKey()
+    if (relayPubkey === event.pubkey) {
+      return
+    }
+
+    const existingVanishRequest = await this.eventRepository.hasActiveRequestToVanish(event.pubkey)
+    if (existingVanishRequest) {
+      return 'blocked: request to vanish active for pubkey'
+    }
   }
 
   protected async isRateLimited(event: Event): Promise<boolean> {

src/handlers/event-strategies/vanish-event-strategy.ts

@@ -0,0 +1,33 @@
+import { createCommandResult } from '../../utils/messages'
+import { createLogger } from '../../factories/logger-factory'
+import { Event } from '../../@types/event'
+import { EventKinds } from '../../constants/base'
+import { IEventRepository } from '../../@types/repositories'
+import { IEventStrategy } from '../../@types/message-handlers'
+import { IWebSocketAdapter } from '../../@types/adapters'
+import { WebSocketAdapterEvent } from '../../constants/adapter'
+
+const debug = createLogger('vanish-event-strategy')
+
+export class VanishEventStrategy implements IEventStrategy<Event, Promise<void>> {
+  public constructor(
+    private readonly webSocket: IWebSocketAdapter,
+    private readonly eventRepository: IEventRepository,
+  ) {}
+
+  public async execute(event: Event): Promise<void> {
+    debug('received request to vanish event: %o', event)
+
+    await this.eventRepository.deleteByPubkeyExceptKinds(
+      event.pubkey,
+      [EventKinds.REQUEST_TO_VANISH],
+    )
+
+    const count = await this.eventRepository.create(event)
+
+    this.webSocket.emit(
+      WebSocketAdapterEvent.Message,
+      createCommandResult(event.id, true, count ? '' : 'duplicate:')
+    )
+  }
+}

src/repositories/event-repository.ts

@@ -28,7 +28,7 @@ import {
   toPairs,
 } from 'ramda'
 
-import { ContextMetadataKey, EventDeduplicationMetadataKey, EventExpirationTimeMetadataKey } from '../constants/base'
+import { ContextMetadataKey, EventDeduplicationMetadataKey, EventExpirationTimeMetadataKey, EventKinds } from '../constants/base'
 import { DatabaseClient, EventId } from '../@types/base'
 import { DBEvent, Event } from '../@types/event'
 import { IEventRepository, IQueryResult } from '../@types/repositories'
@@ -246,9 +246,33 @@ export class EventRepository implements IEventRepository {
     return this.masterDbClient('events')
       .where('event_pubkey', toBuffer(pubkey))
       .whereIn('event_id', map(toBuffer)(eventIdsToDelete))
+      .whereNot('event_kind', EventKinds.REQUEST_TO_VANISH)
       .whereNull('deleted_at')
       .update({
         deleted_at: this.masterDbClient.raw('now()'),
       })
   }
+
+  public deleteByPubkeyExceptKinds(pubkey: string, excludedKinds: number[]): Promise<number> {
+    debug('deleting events from %s except kinds %o', pubkey, excludedKinds)
+
+    return this.masterDbClient('events')
+      .where('event_pubkey', toBuffer(pubkey))
+      .whereNotIn('event_kind', excludedKinds)
+      .whereNull('deleted_at')
+      .update({
+        deleted_at: this.masterDbClient.raw('now()'),
+      })
+  }
+
+  public async hasActiveRequestToVanish(pubkey: string): Promise<boolean> {
+    const result = await this.readReplicaDbClient('events')
+      .select('event_id')
+      .where('event_pubkey', toBuffer(pubkey))
+      .where('event_kind', EventKinds.REQUEST_TO_VANISH)
+      .whereNull('deleted_at')
+      .first()
+
+    return Boolean(result)
+  }
 }

src/utils/event.ts

@@ -1,11 +1,9 @@
 import * as secp256k1 from '@noble/secp256k1'
-
+import { ALL_RELAYS, EventKinds, EventTags } from '../constants/base'
 import { applySpec, pipe, prop } from 'ramda'
 import { CanonicalEvent, DBEvent, Event, UnidentifiedEvent, UnsignedEvent } from '../@types/event'
 import { createCipheriv, getRandomValues } from 'crypto'
 import { EventId, Pubkey, Tag } from '../@types/base'
-import { EventKinds, EventTags } from '../constants/base'
-
 import cluster from 'cluster'
 import { deriveFromSecret } from './secret'
 import { EventKindsRange } from '../@types/settings'
@@ -227,6 +225,18 @@ export const isDeleteEvent = (event: Event): boolean => {
   return event.kind === EventKinds.DELETE
 }
 
+export const isRequestToVanishEvent = (event: Event): boolean => {
+  return event.kind === EventKinds.REQUEST_TO_VANISH
+}
+
+export const isValidRequestToVanishEvent = (event: Event, relayUrl: string): boolean => {
+  const relayTags = event.tags
+    .filter((tag) => tag.length >= 2 && tag[0] === EventTags.Relay)
+    .map((tag) => tag[1])
+
+  return relayTags.length > 0 && relayTags.every((relay) => relay === relayUrl || relay === ALL_RELAYS)
+}
+
 export const isExpiredEvent = (event: Event): boolean => {
   if (!event.tags.length) {
     return false

test/unit/factories/event-strategy-factory.spec.ts

@@ -12,6 +12,7 @@ import { IEventStrategy } from '../../../src/@types/message-handlers'
 import { IWebSocketAdapter } from '../../../src/@types/adapters'
 import { ParameterizedReplaceableEventStrategy } from '../../../src/handlers/event-strategies/parameterized-replaceable-event-strategy'
 import { ReplaceableEventStrategy } from '../../../src/handlers/event-strategies/replaceable-event-strategy'
+import { VanishEventStrategy } from '../../../src/handlers/event-strategies/vanish-event-strategy'
 
 describe('eventStrategyFactory', () => {
   let eventRepository: IEventRepository
@@ -52,6 +53,11 @@ describe('eventStrategyFactory', () => {
     expect(factory([event, adapter])).to.be.an.instanceOf(DeleteEventStrategy)
   })
 
+  it('returns VanishEventStrategy given a request to vanish event', () => {
+    event.kind = EventKinds.REQUEST_TO_VANISH
+    expect(factory([event, adapter])).to.be.an.instanceOf(VanishEventStrategy)
+  })
+
   it('returns ParameterizedReplaceableEventStrategy given a delete event', () => {
     event.kind = EventKinds.PARAMETERIZED_REPLACEABLE_FIRST
     expect(factory([event, adapter])).to.be.an.instanceOf(ParameterizedReplaceableEventStrategy)

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

@@ -23,6 +23,7 @@ describe('EventMessageHandler', () => {
   let webSocket: IWebSocketAdapter
   let handler: EventMessageHandler
   let userRepository: IUserRepository
+  let eventRepository: any
   let event: Event
   let message: IncomingEventMessage
   let sandbox: Sinon.SinonSandbox
@@ -69,6 +70,7 @@ describe('EventMessageHandler', () => {
       canAcceptEventStub = sandbox.stub(EventMessageHandler.prototype, 'canAcceptEvent' as any)
       isEventValidStub = sandbox.stub(EventMessageHandler.prototype, 'isEventValid' as any)
       isUserAdmitted = sandbox.stub(EventMessageHandler.prototype, 'isUserAdmitted' as any)
+      eventRepository = { hasActiveRequestToVanish: sandbox.stub().resolves(false) }
       strategyExecuteStub = sandbox.stub()
       strategyFactoryStub = sandbox.stub().returns({
         execute: strategyExecuteStub,
@@ -81,6 +83,7 @@ describe('EventMessageHandler', () => {
       handler = new EventMessageHandler(
         webSocket as any,
         strategyFactoryStub,
+        eventRepository,
         userRepository,
         () => ({
           info: { relay_url: 'relay_url' },
@@ -119,6 +122,20 @@ describe('EventMessageHandler', () => {
       expect(strategyFactoryStub).not.to.have.been.called
     })
 
+    it('rejects event if request to vanish is active for pubkey', async () => {
+      canAcceptEventStub.returns(undefined)
+      isEventValidStub.resolves(undefined)
+      eventRepository.hasActiveRequestToVanish.resolves(true)
+
+      await handler.handleMessage(message)
+
+      expect(eventRepository.hasActiveRequestToVanish).to.have.been.calledOnceWithExactly(event.pubkey)
+      expect(onMessageSpy).to.have.been.calledOnceWithExactly(
+        [MessageType.OK, event.id, false, 'blocked: request to vanish active for pubkey'],
+      )
+      expect(strategyFactoryStub).not.to.have.been.called
+    })
+
     it('rejects event if invalid', async () => {
       isEventValidStub.resolves('reason')
 
@@ -242,6 +259,7 @@ describe('EventMessageHandler', () => {
       handler = new EventMessageHandler(
         {} as any,
         () => null,
+        { hasActiveRequestToVanish: async () => false } as any,
         userRepository,
         () => settings,
         () => ({ hit: async () => false })
@@ -717,6 +735,7 @@ describe('EventMessageHandler', () => {
       handler = new EventMessageHandler(
         webSocket,
         () => null,
+        { hasActiveRequestToVanish: async () => false } as any,
         userRepository,
         () => settings,
         () => ({ hit: rateLimiterHitStub })
@@ -984,6 +1003,7 @@ describe('EventMessageHandler', () => {
       handler = new EventMessageHandler(
         webSocket,
         () => null,
+        { hasActiveRequestToVanish: async () => false } as any,
         userRepository,
         () => settings,
         () => ({ hit: async () => false })