feat: added a local cache based on browsers built in indexDB

package-lock.json

@@ -21,6 +21,7 @@
         "crypto-js": "^4.2.0",
         "dnd-core": "16.0.1",
         "file-saver": "2.0.5",
+        "idb": "8.0.0",
         "jszip": "3.10.1",
         "lodash": "4.17.21",
         "mui-file-input": "4.0.4",
@@ -3592,6 +3593,11 @@
       "resolved": "https://registry.npmjs.org/react-is/-/react-is-16.13.1.tgz",
       "integrity": "sha512-24e6ynE2H+OKt4kqsOvNd8kBpV65zoxbA4BVsEOB3ARVWQki/DHzaUoC5KuON/BiccDaCCTZBuOcfZs70kR8bQ=="
     },
+    "node_modules/idb": {
+      "version": "8.0.0",
+      "resolved": "https://registry.npmjs.org/idb/-/idb-8.0.0.tgz",
+      "integrity": "sha512-l//qvlAKGmQO31Qn7xdzagVPPaHTxXx199MhrAFuVBTPqydcPYBWjkrbv4Y0ktB+GmWOiwHl237UUOrLmQxLvw=="
+    },
     "node_modules/ignore": {
       "version": "5.3.1",
       "resolved": "https://registry.npmjs.org/ignore/-/ignore-5.3.1.tgz",

package.json

@@ -27,6 +27,7 @@
     "crypto-js": "^4.2.0",
     "dnd-core": "16.0.1",
     "file-saver": "2.0.5",
+    "idb": "8.0.0",
     "jszip": "3.10.1",
     "lodash": "4.17.21",
     "mui-file-input": "4.0.4",

src/services/cache/index.ts

@@ -0,0 +1,54 @@
+import { IDBPDatabase, openDB } from 'idb'
+import { Event } from 'nostr-tools'
+import { CachedMetadataEvent } from '../../types'
+import { SchemaV1 } from './schema'
+
+class LocalCache {
+  // Static property to hold the single instance of LocalCache
+  private static instance: LocalCache | null = null
+  private db!: IDBPDatabase<SchemaV1>
+
+  // Private constructor to prevent direct instantiation
+  private constructor() {}
+
+  // Method to initialize the database
+  private async init() {
+    this.db = await openDB<SchemaV1>('sigit-cache', 1, {
+      upgrade(db) {
+        db.createObjectStore('userMetadata', { keyPath: 'event.pubkey' })
+      }
+    })
+  }
+
+  // Static method to get the single instance of LocalCache
+  public static async getInstance(): Promise<LocalCache> {
+    // If the instance doesn't exist, create it
+    if (!LocalCache.instance) {
+      LocalCache.instance = new LocalCache()
+      await LocalCache.instance.init()
+    }
+    // Return the single instance of LocalCache
+    return LocalCache.instance
+  }
+
+  // Method to add user metadata
+  public async addUserMetadata(event: Event) {
+    await this.db.put('userMetadata', { event, cachedAt: Date.now() })
+  }
+
+  // Method to get user metadata by key
+  public async getUserMetadata(
+    key: string
+  ): Promise<CachedMetadataEvent | null> {
+    const data = await this.db.get('userMetadata', key)
+    return data || null
+  }
+
+  // Method to delete user metadata by key
+  public async deleteUserMetadata(key: string) {
+    await this.db.delete('userMetadata', key)
+  }
+}
+
+// Export the single instance of LocalCache
+export const localCache = await LocalCache.getInstance()

src/services/cache/schema.ts

@@ -0,0 +1,9 @@
+import { DBSchema } from 'idb'
+import { CachedMetadataEvent } from '../../types'
+
+export interface SchemaV1 extends DBSchema {
+  userMetadata: {
+    key: string
+    value: CachedMetadataEvent
+  }
+}

src/services/index.ts

@@ -0,0 +1 @@
+export * from './cache'

src/types/cache.ts

@@ -0,0 +1,6 @@
+import { Event } from 'nostr-tools'
+
+export interface CachedMetadataEvent {
+  event: Event
+  cachedAt: number
+}

src/types/index.ts

@@ -1,5 +1,6 @@
+export * from './cache'
 export * from './core'
 export * from './nostr'
 export * from './profile'
-export * from './zip'
 export * from './relay'
+export * from './zip'