refactor: make GET wallet a bit faster

packages/cashu/cashu.test.ts

@@ -446,7 +446,7 @@ Deno.test('getWallet function is working', async () => {
 
   await relay.event(wallet);
 
-  const walletEntity = await getWallet(relay, pubkey, signer);
+  const { wallet: walletEntity } = await getWallet(relay, pubkey, signer);
 
   assertEquals(walletEntity, {
     balance: 38,

packages/cashu/cashu.ts

@@ -244,12 +244,12 @@ async function getWallet(
   pubkey: string,
   signer: SetRequired<NostrSigner, 'nip44'>,
   opts?: { signal?: AbortSignal },
-): Promise<Wallet | undefined> {
+): Promise<{ wallet: Wallet; error: null } | { wallet: null; error: CustomError }> {
   const { data, error } = await validateAndParseWallet(store, signer, pubkey, { signal: opts?.signal });
 
   if (error) {
     logi({ level: 'error', ns: 'ditto.cashu.get_wallet', error: errorJson(error) });
-    return;
+    return { wallet: null, error };
   }
 
   const { p2pk, mints, relays } = data;
@@ -283,7 +283,7 @@ async function getWallet(
     balance,
   };
 
-  return walletEntity;
+  return { wallet: walletEntity, error: null };
 }
 
 /** Serialize an error into JSON for JSON logging. */

packages/ditto/cache/sessionCache.ts

@@ -0,0 +1,73 @@
+/**
+ * A simple in-memory session cache for storing small pieces of data
+ * with an optional TTL.
+ */
+export class SessionCache {
+  private cache = new Map<string, { value: any; expires?: number }>();
+
+  /**
+   * Set a value in the cache
+   * @param key The cache key
+   * @param value The value to store
+   * @param ttlSec Optional TTL in seconds
+   */
+  set(key: string, value: any, ttlSec?: number): void {
+    const expires = ttlSec ? Date.now() + (ttlSec * 1000) : undefined;
+    this.cache.set(key, { value, expires });
+  }
+
+  /**
+   * Get a value from the cache
+   * @param key The cache key
+   * @returns The cached value or undefined if not found or expired
+   */
+  get(key: string): any {
+    const item = this.cache.get(key);
+
+    if (!item) {
+      return undefined;
+    }
+
+    if (item.expires && item.expires < Date.now()) {
+      this.cache.delete(key);
+      return undefined;
+    }
+
+    return item.value;
+  }
+
+  /**
+   * Remove a value from the cache
+   * @param key The cache key
+   */
+  delete(key: string): void {
+    this.cache.delete(key);
+  }
+
+  /**
+   * Clear all values from the cache
+   */
+  clear(): void {
+    this.cache.clear();
+  }
+
+  /**
+   * Run cleanup to remove expired items
+   */
+  cleanup(): void {
+    const now = Date.now();
+    for (const [key, item] of this.cache.entries()) {
+      if (item.expires && item.expires < now) {
+        this.cache.delete(key);
+      }
+    }
+  }
+}
+
+// Create and export a singleton instance
+export const sessionCache = new SessionCache();
+
+// Run cleanup every minute
+setInterval(() => {
+  sessionCache.cleanup();
+}, 60 * 1000);

packages/ditto/cache/walletCache.ts

@@ -0,0 +1,133 @@
+import { Wallet } from '@ditto/cashu';
+import { logi } from '@soapbox/logi';
+import { errorJson } from '@/utils/log.ts';
+
+/**
+ * A simple in-memory cache for wallet data
+ * - Keys are pubkeys
+ * - Values are wallet data and timestamp
+ */
+interface CachedWallet {
+  wallet: Wallet;
+  timestamp: number;
+  lastQueryTimestamp: number;
+}
+
+export class WalletCache {
+  private cache = new Map<string, CachedWallet>();
+  private ttlMs: number;
+  private queryTtlMs: number;
+
+  /**
+   * @param ttlSec Cache TTL in seconds
+   * @param queryTtlSec How long we should wait between full queries in seconds
+   */
+  constructor(ttlSec = 60, queryTtlSec = 5) {
+    this.ttlMs = ttlSec * 1000;
+    this.queryTtlMs = queryTtlSec * 1000;
+
+    // Periodic cleanup
+    setInterval(() => this.cleanup(), 60 * 1000);
+  }
+
+  /**
+   * Get wallet from cache
+   * @param pubkey User's pubkey
+   * @returns The cached wallet if present and valid, null otherwise
+   */
+  get(pubkey: string): { wallet: Wallet; shouldRefresh: boolean } | null {
+    const entry = this.cache.get(pubkey);
+    if (!entry) {
+      return null;
+    }
+
+    const now = Date.now();
+    const age = now - entry.timestamp;
+
+    // If cache entry is too old, consider it invalid
+    if (age > this.ttlMs) {
+      return null;
+    }
+
+    // Check if we should refresh the data in the background
+    // This is determined by how long since the last full query
+    const queryAge = now - entry.lastQueryTimestamp;
+    const shouldRefresh = queryAge > this.queryTtlMs;
+
+    return { wallet: entry.wallet, shouldRefresh };
+  }
+
+  /**
+   * Store wallet in cache
+   * @param pubkey User's pubkey
+   * @param wallet Wallet data
+   * @param isQueryResult Whether this is from a full query or just a balance update
+   */
+  set(pubkey: string, wallet: Wallet, isQueryResult = true): void {
+    const now = Date.now();
+    const existing = this.cache.get(pubkey);
+
+    this.cache.set(pubkey, {
+      wallet,
+      timestamp: now,
+      // If this is just a balance update, preserve the lastQueryTimestamp
+      lastQueryTimestamp: isQueryResult ? now : (existing?.lastQueryTimestamp || now),
+    });
+  }
+
+  /**
+   * Update balance for a wallet without doing a full refresh
+   * @param pubkey User's pubkey
+   * @param deltaAmount Amount to add to balance (negative to subtract)
+   * @returns true if updated, false if wallet not in cache
+   */
+  updateBalance(pubkey: string, deltaAmount: number): boolean {
+    const entry = this.cache.get(pubkey);
+    if (!entry) {
+      return false;
+    }
+
+    const newWallet = {
+      ...entry.wallet,
+      balance: entry.wallet.balance + deltaAmount,
+    };
+
+    this.set(pubkey, newWallet, false);
+    return true;
+  }
+
+  /**
+   * Remove expired entries from cache
+   */
+  private cleanup(): void {
+    const now = Date.now();
+    let deletedCount = 0;
+
+    for (const [pubkey, entry] of this.cache.entries()) {
+      if (now - entry.timestamp > this.ttlMs) {
+        this.cache.delete(pubkey);
+        deletedCount++;
+      }
+    }
+
+    if (deletedCount > 0) {
+      logi({
+        level: 'debug',
+        ns: 'ditto.cache.wallet',
+        message: `Cleaned up ${deletedCount} expired wallet cache entries`,
+      });
+    }
+  }
+
+  /**
+   * Get cache statistics
+   */
+  getStats(): { size: number } {
+    return {
+      size: this.cache.size,
+    };
+  }
+}
+
+// Singleton instance
+export const walletCache = new WalletCache();

packages/ditto/controllers/api/cashu.ts

@@ -1,13 +1,5 @@
 import { CashuMint, CashuWallet, MintQuoteState, Proof } from '@cashu/cashu-ts';
-import {
-  getWallet,
-  organizeProofs,
-  proofSchema,
-  renderTransaction,
-  tokenEventSchema,
-  validateAndParseWallet,
-  type Wallet,
-} from '@ditto/cashu';
+import { getWallet, organizeProofs, proofSchema, renderTransaction, tokenEventSchema, type Wallet } from '@ditto/cashu';
 import { userMiddleware } from '@ditto/mastoapi/middleware';
 import { paginated, paginationSchema } from '@ditto/mastoapi/pagination';
 import { DittoRoute } from '@ditto/mastoapi/router';
@@ -28,13 +20,6 @@ import { DittoEvent } from '@/interfaces/DittoEvent.ts';
 
 const route = new DittoRoute();
 
-interface Nutzap {
-  amount: number;
-  event_id?: string;
-  mint: string; // mint the nutzap was created
-  recipient_pubkey: string;
-}
-
 const createMintQuoteSchema = z.object({
   mint: z.string().url(),
   amount: z.number().int(),
@@ -258,18 +243,13 @@ route.get('/wallet', userMiddleware({ enc: 'nip44' }), swapNutzapsMiddleware, as
 
   const pubkey = await user.signer.getPublicKey();
 
-  const { error } = await validateAndParseWallet(relay, user.signer, pubkey, { signal });
+  const { wallet, error } = await getWallet(relay, pubkey, user.signer, { signal });
+
   if (error) {
     return c.json({ error: error.message }, 404);
   }
 
-  const walletEntity = await getWallet(relay, pubkey, user.signer);
-
-  if (!walletEntity) {
-    return c.json({ 'error': 'Wallet not found' }, 404);
-  }
-
-  return c.json(walletEntity, 200);
+  return c.json(wallet, 200);
 });
 
 /** Gets a history of transactions. */