feat: implement nip-09 event deletion

README.md

@@ -14,7 +14,7 @@ NIPs with a relay-specific implementation are listed here.
 - [ ] NIP-03: OpenTimestams Attestations for Events
 - [x] NIP-04: Encrypted Direct Message
 - [ ] NIP-05: Mapping Nostr keys to DNS identifiers
-- [ ] NIP-09: Event deletion
+- [x] NIP-09: Event deletion
 - [x] NIP-11: Relay information document
 - [x] NIP-12: Generic tag queries
 - [ ] NIP-13: Proof of Work

src/@types/event.ts

@@ -3,7 +3,9 @@ import { Pubkey, TagName } from './base'
 
 export type EventId = string
 
-export interface Tag {
+export type Tag = TagBase | []
+
+export interface TagBase {
   0: TagName
   [index: number]: string
 }

src/@types/repositories.ts

@@ -1,5 +1,6 @@
 import { PassThrough } from 'stream'
-import { DBEvent, Event } from './event'
+import { Pubkey } from './base'
+import { DBEvent, Event, EventId } from './event'
 import { SubscriptionFilter } from './subscription'
 
 export type ExposedPromiseKeys = 'then' | 'catch' | 'finally'
@@ -12,4 +13,5 @@ export interface IEventRepository {
   create(event: Event): Promise<number>
   upsert(event: Event): Promise<number>
   findByFilters(filters: SubscriptionFilter[]): IQueryResult<DBEvent[]>
+  deleteByPubkeyAndIds(pubkey: Pubkey, ids: EventId[]): Promise<number>
 }

src/adapters/web-server-adapter.ts

@@ -32,7 +32,7 @@ export class WebServerAdapter extends EventEmitter implements IWebServerAdapter
         description,
         pubkey,
         contact,
-        supported_nips: [1, 2, 4, 11, 12, 15, 16],
+        supported_nips: [1, 2, 4, 9, 11, 12, 15, 16],
         software: packageJson.repository.url,
         version: packageJson.version,
       }

src/constants/base.ts

@@ -7,3 +7,8 @@ export enum EventKinds {
   DELETE = 5,
   REACTION = 7,
 }
+
+export enum EventTags {
+  Event = 'e',
+  Pubkey = 'p',
+}

src/factories/event-strategy-factory.ts

@@ -1,13 +1,14 @@
 import { DefaultEventStrategy } from '../handlers/event-strategies/default-event-strategy'
 import { EphemeralEventStrategy } from '../handlers/event-strategies/ephemeral-event-strategy'
-import { NullEventStrategy } from '../handlers/event-strategies/null-event-strategy copy'
+import { NullEventStrategy } from '../handlers/event-strategies/null-event-strategy'
 import { ReplaceableEventStrategy } from '../handlers/event-strategies/replaceable-event-strategy'
 import { Factory } from '../@types/base'
 import { Event } from '../@types/event'
 import { IEventStrategy } from '../@types/message-handlers'
 import { IEventRepository } from '../@types/repositories'
-import { isEphemeralEvent, isNullEvent, isReplaceableEvent } from '../utils/event'
+import { isDeleteEvent, isEphemeralEvent, isNullEvent, isReplaceableEvent } from '../utils/event'
 import { IWebSocketAdapter } from '../@types/adapters'
+import { DeleteEventStrategy } from '../handlers/event-strategies/delete-event-strategy'
 
 
 export const eventStrategyFactory = (
@@ -19,6 +20,8 @@ export const eventStrategyFactory = (
     return new EphemeralEventStrategy(adapter)
   } else if (isNullEvent(event)) {
     return new NullEventStrategy()
+  } else if (isDeleteEvent(event)) {
+    return new DeleteEventStrategy(eventRepository)
   }
 
   return new DefaultEventStrategy(adapter, eventRepository)

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

@@ -0,0 +1,33 @@
+import { Event } from '../../@types/event'
+import { IEventStrategy } from '../../@types/message-handlers'
+import { IEventRepository } from '../../@types/repositories'
+import { EventTags } from '../../constants/base'
+
+
+export class DeleteEventStrategy implements IEventStrategy<Event, Promise<boolean>> {
+  public constructor(
+    private readonly eventRepository: IEventRepository,
+  ) { }
+
+  public async execute(event: Event): Promise<boolean> {
+    try {
+      const eTags = event.tags.filter((tag) => tag[0] === EventTags.Event)
+
+      if (!eTags.length) {
+        return
+      }
+
+      await this.eventRepository.deleteByPubkeyAndIds(
+        event.pubkey,
+        eTags.map((tag) => tag[1])
+      )
+
+      return
+    } catch (error) {
+      console.error('Unable to handle event. Reason:', error)
+
+      return false
+    }
+  }
+
+}

src/repositories/event-repository.ts

@@ -1,7 +1,7 @@
 import { Knex } from 'knex'
-import { __, applySpec, equals, modulo, omit, pipe, prop, cond, always, groupBy, T, evolve, forEach, isEmpty, forEachObjIndexed, isNil, complement, toPairs, filter, nth, ifElse, invoker } from 'ramda'
+import { __, applySpec, equals, modulo, omit, pipe, prop, cond, always, groupBy, T, evolve, forEach, isEmpty, forEachObjIndexed, isNil, complement, toPairs, filter, nth, ifElse, invoker, identity } from 'ramda'
 
-import { DBEvent, Event } from '../@types/event'
+import { DBEvent, Event, EventId } from '../@types/event'
 import { IEventRepository, IQueryResult } from '../@types/repositories'
 import { SubscriptionFilter } from '../@types/subscription'
 import { isGenericTagQuery } from '../utils/filter'
@@ -156,4 +156,15 @@ export class EventRepository implements IEventRepository {
       .where('events.event_created_at', '<', row.event_created_at)
       .then(prop('rowCount') as () => number)
   }
+
+  public async deleteByPubkeyAndIds(pubkey: string, ids: EventId[]): Promise<number> {
+    const query = this.dbClient('events')
+      .where({
+        event_pubkey: pubkey,
+      })
+      .whereIn('event_id', ids)
+      .delete()
+
+    return query.then(identity)
+  }
 }

src/utils/event.ts

@@ -3,6 +3,7 @@ import { applySpec, pipe, prop } from 'ramda'
 
 import { CanonicalEvent, Event } from '../@types/event'
 import { SubscriptionFilter } from '../@types/subscription'
+import { EventKinds } from '../constants/base'
 import { isGenericTagQuery } from './filter'
 import { fromBuffer } from './transform'
 
@@ -95,3 +96,7 @@ export const isEphemeralEvent = (event: Event): boolean => {
 export const isNullEvent = (event: Event): boolean => {
   return event.kind === Number.MAX_SAFE_INTEGER
 }
+
+export const isDeleteEvent = (event: Event): boolean => {
+  return event.kind === EventKinds.DELETE
+}

test/unit/repositories/event-repository.spec.ts

@@ -11,7 +11,7 @@ const { expect } = chai
 
 import { EventRepository } from '../../../src/repositories/event-repository'
 
-describe.only('EventRepository', () => {
+describe('EventRepository', () => {
   let repository: IEventRepository
   let sandbox: sinon.SinonSandbox