src/controllers/MetadataController.ts

@@ -16,6 +16,12 @@ import { queryNip05 } from '../utils'
 import NDK, { NDKEvent, NDKSubscription } from '@nostr-dev-kit/ndk'
 import { EventEmitter } from 'tseep'
 import { localCache } from '../services'
+import {
+  findRelayListAndUpdateCache,
+  findRelayListInCache,
+  getDefaultRelaySet,
+  getUserRelaySet
+} from '../utils/relays.ts'
 
 export class MetadataController extends EventEmitter {
   private nostrController: NostrController
@@ -144,100 +150,27 @@ export class MetadataController extends EventEmitter {
     return this.checkForMoreRecentMetadata(hexKey, null)
   }
 
-  public findRelayListMetadata = async (hexKey: string) => {
+  /**
-    let relayEvent: Event | null = null
+   * Based on the hexKey of the current user, this method attempts to retrieve a relay set.
+   * @func findRelayListInCache first checks if there is already an up-to-date
+   * relay list available in cache; if not -
+   * @func findRelayListAndUpdateCache checks if the relevant relay event is available from
+   * the purple pages relay;
+   * @func findRelayListAndUpdateCache will run again if the previous two calls return null and
+   * check if the relevant relay event can be obtained from 'most popular relays'
+   * If relay event is found, it will be saved in cache for future use
+   * @param hexKey of the current user
+   * @return RelaySet which will contain either relays extracted from the user Relay Event
+   * or a fallback RelaySet with Sigit's Relay
+   */
+  public findRelayListMetadata = async (hexKey: string): Promise<RelaySet> => {
+    const relayEvent = await findRelayListInCache(hexKey)
+      || await findRelayListAndUpdateCache([this.specialMetadataRelay], hexKey)
+      || await findRelayListAndUpdateCache(await this.nostrController.getMostPopularRelays(), hexKey)
 
-    // Attempt to retrieve the metadata event from the local cache
+    return relayEvent
-    const cachedRelayListMetadataEvent =
+      ? getUserRelaySet(relayEvent.tags)
-      await localCache.getUserRelayListMetadata(hexKey)
+      : getDefaultRelaySet()
-
-    if (cachedRelayListMetadataEvent) {
-      const oneWeekInMS = 7 * 24 * 60 * 60 * 1000 // Number of milliseconds in one week
-
-      // Check if the cached event is not older than one week
-      if (Date.now() - cachedRelayListMetadataEvent.cachedAt < oneWeekInMS) {
-        relayEvent = cachedRelayListMetadataEvent.event
-      }
-    }
-
-    // define filter for relay list
-    const eventFilter: Filter = {
-      kinds: [kinds.RelayList],
-      authors: [hexKey]
-    }
-
-    const pool = new SimplePool()
-
-    // Try to get the relayList event from a special relay (wss://purplepag.es)
-    if (!relayEvent) {
-      relayEvent = await pool
-        .get([this.specialMetadataRelay], eventFilter)
-        .then((event) => {
-          if (event) {
-            // update the event in local cache
-            localCache.addUserRelayListMetadata(event)
-          }
-          return event
-        })
-        .catch((err) => {
-          console.error(err)
-          return null
-        })
-    }
-
-    if (!relayEvent) {
-      // If no valid relayList event is found from the special relay, get the most popular relays
-      const mostPopularRelays =
-        await this.nostrController.getMostPopularRelays()
-
-      // Query the most popular relays for relayList event
-      relayEvent = await pool
-        .get(mostPopularRelays, eventFilter)
-        .then((event) => {
-          if (event) {
-            // update the event in local cache
-            localCache.addUserRelayListMetadata(event)
-          }
-          return event
-        })
-        .catch((err) => {
-          console.error(err)
-          return null
-        })
-    }
-
-    if (relayEvent) {
-      const relaySet: RelaySet = {
-        read: [],
-        write: []
-      }
-
-      // a list of r tags with relay URIs and a read or write marker.
-      const relayTags = relayEvent.tags.filter((tag) => tag[0] === 'r')
-
-      // Relays marked as read / write are called READ / WRITE relays, respectively
-      relayTags.forEach((tag) => {
-        if (tag.length >= 3) {
-          const marker = tag[2]
-
-          if (marker === 'read') {
-            relaySet.read.push(tag[1])
-          } else if (marker === 'write') {
-            relaySet.write.push(tag[1])
-          }
-        }
-
-        // If the marker is omitted, the relay is used for both purposes
-        if (tag.length === 2) {
-          relaySet.read.push(tag[1])
-          relaySet.write.push(tag[1])
-        }
-      })
-
-      return relaySet
-    }
-
-    throw new Error('No relay list metadata found.')
   }
 
   public extractProfileMetadataContent = (event: Event) => {

src/utils/const.ts

@@ -4,3 +4,9 @@ export const EMPTY: string = ''
 export const MARK_TYPE_TRANSLATION: { [key: string]: string } = {
   [MarkType.FULLNAME.valueOf()]: 'Full Name'
 }
+/**
+ * Number of milliseconds in one week.
+ * Calc based on: 7 * 24 * 60 * 60 * 1000
+ */
+export const ONE_WEEK_IN_MS: number = 604800000
+export const SIGIT_RELAY: string = 'wss://relay.sigit.io'

src/utils/relays.ts

@@ -0,0 +1,108 @@
+import { Filter, SimplePool } from 'nostr-tools'
+import { RelayList } from 'nostr-tools/kinds'
+import { Event } from 'nostr-tools'
+import { localCache } from '../services'
+import { ONE_WEEK_IN_MS, SIGIT_RELAY } from './const.ts'
+import { RelayMap, RelaySet } from '../types'
+
+const READ_MARKER = "read"
+const WRITE_MARKET = "write"
+
+/**
+ * Attempts to find a relay list from the provided lookUpRelays.
+ * If the relay list is found, it will be added to the user relay list metadata.
+ * @param lookUpRelays
+ * @param hexKey
+ * @return found relay list or null
+ */
+const findRelayListAndUpdateCache = async (lookUpRelays: string[], hexKey: string): Promise<Event | null> => {
+  try {
+    const eventFilter: Filter = {
+      kinds: [RelayList],
+      authors: [hexKey]
+    }
+    const pool = new SimplePool()
+    const event = await pool.get(lookUpRelays, eventFilter)
+    if (event) {
+      await localCache.addUserRelayListMetadata(event)
+    }
+    return event
+  } catch (error) {
+    console.error(error)
+    return null
+  }
+}
+
+/**
+ * Attempts to find a relay list in cache. If it is present, it will check that the cached event is not
+ * older than one week.
+ * @param hexKey
+ * @return RelayList event if it's not older than a week; otherwise null
+ */
+const findRelayListInCache = async (hexKey: string): Promise<Event | null> => {
+  try {
+    // Attempt to retrieve the metadata event from the local cache
+    const cachedRelayListMetadataEvent = await localCache.getUserRelayListMetadata(hexKey)
+
+    // Check if the cached event is not older than one week
+    if (cachedRelayListMetadataEvent && isOlderThanOneWeek(cachedRelayListMetadataEvent.cachedAt)) {
+      return cachedRelayListMetadataEvent.event
+    }
+
+    return null
+  } catch (error) {
+    console.error(error)
+    return null
+  }
+}
+
+/**
+ * Transforms a list of relay tags from a Nostr Event to a RelaySet.
+ * @param tags
+ */
+const getUserRelaySet = (tags: string[][]): RelaySet => {
+  return tags
+    .filter(isRelayTag)
+    .reduce<RelaySet>(toRelaySet, getDefaultRelaySet())
+}
+
+const getDefaultRelaySet = (): RelaySet => ({
+  read: [SIGIT_RELAY],
+  write: [SIGIT_RELAY]
+})
+
+const getDefaultRelayMap = (): RelayMap => ({
+  [SIGIT_RELAY]: { write: true, read: true }
+})
+
+const isOlderThanOneWeek = (cachedAt: number) => {
+  return Date.now() - cachedAt < ONE_WEEK_IN_MS
+}
+
+const isRelayTag = (tag: string[]): boolean => tag[0] === 'r'
+
+const toRelaySet = (obj: RelaySet, tag: string[]): RelaySet => {
+  if (tag.length >= 3) {
+    const marker = tag[2]
+
+    if (marker === READ_MARKER) {
+      obj.read.push(tag[1])
+    } else if (marker === WRITE_MARKET) {
+      obj.write.push(tag[1])
+    }
+  }
+  if (tag.length === 2) {
+    obj.read.push(tag[1])
+    obj.write.push(tag[1])
+  }
+
+  return obj
+}
+
+export {
+  findRelayListAndUpdateCache,
+  findRelayListInCache,
+  getUserRelaySet,
+  getDefaultRelaySet,
+  getDefaultRelayMap,
+}