feat: implement nip-27

README.md

@@ -13,7 +13,6 @@ NIPs with a relay-specific implementation are listed here.
 - [x] NIP-02: Contact list and petnames
 - [ ] NIP-03: OpenTimestams Attestations for Events
 - [x] NIP-04: Encrypted Direct Message
-- [ ] NIP-05: Mapping Nostr keys to DNS identifiers
 - [x] NIP-09: Event deletion
 - [x] NIP-11: Relay information document
 - [x] NIP-12: Generic tag queries
@@ -21,6 +20,7 @@ NIPs with a relay-specific implementation are listed here.
 - [x] NIP-15: End of Stored Events Notice
 - [x] NIP-16: Event Treatment
 - [ ] NIP-25: Reactions
+- [x] NIP-27: Multicasting (Experimental)
 
 ## Requirements
 

src/@types/base.ts

@@ -1,6 +1,13 @@
+export type EventId = string
 export type Pubkey = string
 export type TagName = string
 export type Signature = string
+export type Tag = TagBase & string[]
+
+export interface TagBase {
+  0: TagName
+  [index: number]: string
+}
 
 type Enumerate<
   N extends number,

src/@types/event.ts

@@ -1,14 +1,6 @@
 import { EventKinds } from '../constants/base'
-import { Pubkey, TagName } from './base'
+import { EventId, Pubkey, Tag } from './base'
 
-export type EventId = string
-
-export type Tag = TagBase & string[]
-
-export interface TagBase {
-  0: TagName
-  [index: number]: string
-}
 
 export interface Event {
   id: EventId

src/@types/repositories.ts

@@ -1,6 +1,6 @@
 import { PassThrough } from 'stream'
-import { Pubkey } from './base'
+import { EventId, Pubkey } from './base'
-import { DBEvent, Event, EventId } from './event'
+import { DBEvent, Event } from './event'
 import { SubscriptionFilter } from './subscription'
 
 export type ExposedPromiseKeys = 'then' | 'catch' | 'finally'

src/@types/subscription.ts

@@ -1,6 +1,5 @@
 import { EventKinds } from '../constants/base'
-import { Pubkey } from './base'
+import { EventId, Pubkey } from './base'
-import { EventId } from './event'
 
 export type SubscriptionId = string
 

src/constants/base.ts

@@ -11,4 +11,5 @@ export enum EventKinds {
 export enum EventTags {
   Event = 'e',
   Pubkey = 'p',
+  Multicast = 'm',
 }

src/handlers/subscribe-message-handler.ts

@@ -6,9 +6,10 @@ import { SubscribeMessage } from '../@types/messages'
 import { IWebSocketAdapter } from '../@types/adapters'
 import { IEventRepository } from '../@types/repositories'
 import { SubscriptionId, SubscriptionFilter } from '../@types/subscription'
-import { toNostrEvent } from '../utils/event'
+import { isEventMatchingFilter, toNostrEvent } from '../utils/event'
-import { streamEach, streamEnd, streamMap } from '../utils/stream'
+import { streamEach, streamEnd, streamFilter, streamMap } from '../utils/stream'
 import { Event } from '../@types/event'
+import { anyPass, map } from 'ramda'
 
 
 export class SubscribeMessageHandler implements IMessageHandler, IAbortable {
@@ -39,6 +40,7 @@ export class SubscribeMessageHandler implements IMessageHandler, IAbortable {
       await pipeline(
         findEvents,
         streamMap(toNostrEvent),
+        streamFilter(anyPass(map(isEventMatchingFilter)(filters))),
         streamEach(sendEvent),
         streamEnd(sendEOSE), // NIP-15: End of Stored Events Notice
         {

src/repositories/event-repository.ts

@@ -1,7 +1,8 @@
 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, identity } from 'ramda'
+import { EventId } from '../@types/base'
 
-import { DBEvent, Event, EventId } from '../@types/event'
+import { DBEvent, Event } from '../@types/event'
 import { IEventRepository, IQueryResult } from '../@types/repositories'
 import { SubscriptionFilter } from '../@types/subscription'
 import { isGenericTagQuery } from '../utils/filter'
@@ -83,7 +84,6 @@ export class EventRepository implements IEventRepository {
       const andWhereRaw = invoker(1, 'andWhereRaw')
       const orWhereRaw = invoker(2, 'orWhereRaw')
 
-
       pipe(
         toPairs,
         filter(pipe(nth(0), isGenericTagQuery)) as any,

src/utils/event.ts

@@ -3,7 +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 { EventKinds, EventTags } from '../constants/base'
 import { isGenericTagQuery } from './filter'
 import { fromBuffer } from './transform'
 
@@ -29,6 +29,8 @@ export const toNostrEvent = applySpec({
 export const isEventMatchingFilter = (filter: SubscriptionFilter) => (event: Event): boolean => {
   const startsWith = (input: string) => (prefix) => input.startsWith(prefix)
 
+  // NIP-01: Basic protocol flow description
+
   if (Array.isArray(filter.ids) && (
     !filter.ids.some(startsWith(event.id))
   )) {
@@ -54,6 +56,18 @@ export const isEventMatchingFilter = (filter: SubscriptionFilter) => (event: Eve
     return false
   }
 
+  // NIP-27: Multicast
+  const targetMulticastGroups: string[] = event.tags.reduce(
+    (acc, tag) => (tag[0] === EventTags.Multicast)
+      ? [...acc, tag[1]]
+      : acc,
+    [] as string[]
+  )
+
+  if (targetMulticastGroups.length && !Array.isArray(filter['#m'])) {
+    return false
+  }
+
   // NIP-01: Support #e and #p tags
   // NIP-12: Support generic tag queries
 

src/utils/stream.ts

@@ -15,6 +15,17 @@ export const streamEach = (writeFn: (chunk: any) => void) => new PassThrough({
   },
 })
 
+export const streamFilter = (predicate: (chunk: any) => boolean) => new Transform({
+  objectMode: true,
+  transform(chunk, _encoding, callback) {
+    if (predicate(chunk)) {
+      return callback(null, chunk)
+    }
+
+    callback()
+  },
+})
+
 export const streamEnd = (finalFn: () => void) => new PassThrough({
   objectMode: true,
   final(callback) {

test/unit/utils/event.spec.ts

@@ -76,6 +76,7 @@ describe('NIP-01', () => {
       it('returns true if ids with prefix matches event', () => {
         const event: Event = {
           id: '7377fa81fc6c7ae7f7f4ef8938d4a603f7bf98183b35ab128235cc92d4bebf96',
+          tags: [],
         } as any
         const prefix = '7377fa81fc6c'
 
@@ -86,6 +87,7 @@ describe('NIP-01', () => {
       it('returns false if ids with prefix does not matches event', () => {
         const event: Event = {
           id: '7377fa81fc6c7ae7f7f4ef8938d4a603f7bf98183b35ab128235cc92d4bebf96',
+          tags: [],
         } as any
         const prefix = '001122'
 
@@ -112,6 +114,7 @@ describe('NIP-01', () => {
       it('returns true if authors with prefix matches event', () => {
         const event: Event = {
           pubkey: '22e804d26ed16b68db5259e78449e96dab5d464c8f470bda3eb1a70467f2c793',
+          tags: [],
         } as any
         const prefix = '22e804d'
 
@@ -122,6 +125,7 @@ describe('NIP-01', () => {
       it('returns false if authors with prefix does not matches event', () => {
         const event: Event = {
           pubkey: '22e804d26ed16b68db5259e78449e96dab5d464c8f470bda3eb1a70467f2c793',
+          tags: [],
         } as any
         const prefix = '001122'
 
@@ -330,3 +334,56 @@ describe('isNullEvent', () => {
     expect(isNullEvent({ kind: Number.MAX_SAFE_INTEGER - 1 } as any)).to.be.false
   })
 })
+
+describe('NIP-27', () => {
+  describe('isEventMatchingFilter', () => {
+    describe('#m filter', () => {
+      let event: Event
+      beforeEach(() => {
+        event = {
+          tags: [
+            [
+              'm',
+              'group',
+            ],
+          ],
+        } as any
+      })
+
+      it('returns true given non-multicast event and there is no #m filter', () => {
+        event.tags = []
+        expect(isEventMatchingFilter({})(event)).to.be.true
+      })
+
+      it('returns true given multicast event and contained in #m filter', () => {
+        expect(isEventMatchingFilter({ '#m': ['group'] })(event)).to.be.true
+      })
+
+      it('returns true given multicast event and contained second in #m filter', () => {
+        expect(isEventMatchingFilter({ '#m': ['some group', 'group'] })(event)).to.be.true
+      })
+
+      it('returns false given multicast event and not contained in #m filter', () => {
+        expect(isEventMatchingFilter({ '#m': ['other group'] })(event)).to.be.false
+      })
+
+      it('returns false if given multicast event and there is no #m filter', () => {
+        expect(isEventMatchingFilter({})(event)).to.be.false
+      })
+
+      it('returns false if given multicast event and #m filter is empty', () => {
+        expect(isEventMatchingFilter({ '#m': [] })(event)).to.be.false
+      })
+
+      it('returns false given non-multicast event and filter contains some group', () => {
+        event.tags = []
+        expect(isEventMatchingFilter({ '#m': ['group'] })(event)).to.be.false
+      })
+
+      it('returns false given non-multicast event and filter is empty', () => {
+        event.tags = []
+        expect(isEventMatchingFilter({ '#m': [] })(event)).to.be.false
+      })
+    })
+  })
+})