add ndk cache

src/libs/ndk/cache.tsx

@@ -0,0 +1,56 @@
+import { NDKCacheAdapter } from '@nostr-dev-kit/ndk';
+import { NDKEvent, NDKSubscription } from '@nostr-dev-kit/ndk';
+import { Store } from '@tauri-apps/plugin-store';
+
+export default class TauriAdapter implements NDKCacheAdapter {
+  public store: Store;
+  readonly locking: boolean;
+
+  constructor() {
+    this.store = new Store('.ndkcache.dat');
+    this.locking = true;
+  }
+
+  public async query(subscription: NDKSubscription): Promise<void> {
+    const { filter } = subscription;
+
+    // if this filter uses both authors and kinds, then we need to query for each combination of author and kind
+    // and then combine the results
+    if (filter.authors && filter.kinds) {
+      const promises = [];
+
+      for (const author of filter.authors) {
+        for (const kind of filter.kinds) {
+          const key = `${author}:${kind}`;
+          promises.push(this.store.get(key));
+        }
+      }
+
+      const results = await Promise.all(promises);
+
+      for (const result of results) {
+        if (result) {
+          const event = await this.store.get(result as string);
+
+          if (event) {
+            const ndkEvent = new NDKEvent(subscription.ndk, JSON.parse(event as string));
+            subscription.eventReceived(ndkEvent, undefined, true);
+          }
+        }
+      }
+    }
+  }
+
+  public async setEvent(event: NDKEvent): Promise<void> {
+    const nostrEvent = await event.toNostrEvent();
+    const key = `${nostrEvent.pubkey}:${nostrEvent.kind}`;
+
+    return new Promise((resolve) => {
+      Promise.all([
+        this.store.set(event.id, JSON.stringify(nostrEvent)),
+        this.store.set(key, event.id),
+        this.store.save(),
+      ]).then(() => resolve());
+    });
+  }
+}

src/libs/ndk/instance.ts

@@ -4,6 +4,7 @@ import { ndkAdapter } from '@nostr-fetch/adapter-ndk';
 import { NostrFetcher, normalizeRelayUrlSet } from 'nostr-fetch';
 import { useEffect, useState } from 'react';
 
+import TauriAdapter from '@libs/ndk/cache';
 import { getSetting } from '@libs/storage';
 
 const setting = await getSetting('relays');
@@ -19,7 +20,8 @@ export const NDKInstance = () => {
   }, []);
 
   async function loadNdk(explicitRelayUrls: string[]) {
-    const ndkInstance = new NDK({ explicitRelayUrls });
+    const cacheAdapter = new TauriAdapter();
+    const ndkInstance = new NDK({ explicitRelayUrls, cacheAdapter });
 
     try {
       await ndkInstance.connect();