feat: add eventVerifier to FetcherOptions, to make the event verifica…

…tion logic customizable
jiftechnify · Oct 4, 2024 · 75810b3 · 75810b3
1 parent d587d2b
commit 75810b3
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Showing 4 changed files with 30 additions and 4 deletions.
diff --git a/packages/kernel/src/fetcherBackend.ts b/packages/kernel/src/fetcherBackend.ts
@@ -7,6 +7,7 @@ export type EnsureRelaysOptions = {
 
 export type FetchTillEoseOptions = {
   subId?: string;
+  eventVerifier: (event: NostrEvent) => boolean;
   skipVerification: boolean;
   skipFilterMatching: boolean;
   connectTimeoutMs: number;

diff --git a/packages/nostr-fetch/src/fetcher.ts b/packages/nostr-fetch/src/fetcher.ts
@@ -101,6 +101,31 @@ export type NostrEventWithAuthor<SeenOn extends boolean> = {
  * Common options for all the fetch methods.
  */
 export type FetchOptions<SeenOn extends boolean = false> = {
+  /**
+   * If specified, the fetcher uses the given function as an event signature verifier instead of the default one.
+   *
+   * The function must return `true` if the event signature is valid. Otherwise, it should return `false`.
+   *
+   * @example
+   * // How to use nostr-wasm's verifyEvent() with nostr-fetch
+   * import { NostrFetcher, type NostrEvent } from "nostr-fetch";
+   * import { initNostrWasm } from "nostr-wasm";
+   *
+   * const nw = await initNostrWasm();
+   * const nwVerifyEvent = (ev: NostrEvent) => {
+   *   try {
+   *     nw.verifyEvent(ev);
+   *     return true;
+   *   } catch {
+   *     return false;
+   *   }
+   * };
+   * const fetcher = NostrFetcher.init({
+   *   eventVerifier: nwVerifyEvent,
+   * });
+   */
+  eventVerifier?: (event: NostrEvent) => boolean;
+
   /**
    * If true, the fetcher skips event signature verification.
    *
@@ -173,6 +198,7 @@ export type FetchOptions<SeenOn extends boolean = false> = {
 };
 
 const defaultFetchOptions: Required<FetchOptions> = {
+  eventVerifier: verifyEventSig,
   skipVerification: false,
   skipFilterMatching: false,
   withSeenOn: false,

diff --git a/packages/nostr-fetch/src/relay.ts b/packages/nostr-fetch/src/relay.ts
@@ -1,4 +1,3 @@
-import { verifyEventSig } from "@nostr-fetch/kernel/crypto";
 import type { C2RMessage, Filter, NostrEvent } from "@nostr-fetch/kernel/nostr";
 import { FilterMatcher, generateSubId, parseR2CMessage } from "@nostr-fetch/kernel/nostr";
 import {
@@ -241,6 +240,7 @@ export interface Subscription {
 
 export interface SubscriptionOptions {
   subId?: string;
+  eventVerifier: (event: NostrEvent) => boolean;
   skipVerification: boolean;
   skipFilterMatching: boolean;
   abortSubBeforeEoseTimeoutMs: number;
@@ -317,7 +317,7 @@ class RelaySubscription implements Subscription {
   _forwardEvent(ev: NostrEvent) {
     this.#resetAbortSubTimer();
 
-    if (!this.#options.skipVerification && !verifyEventSig(ev)) {
+    if (!this.#options.skipVerification && !this.#options.eventVerifier(ev)) {
       return;
     }
     if (!this.#options.skipFilterMatching && !this.#filterMatcher.match(ev)) {

diff --git a/packages/nostr-fetch/src/testutil/fakedFetcher.ts b/packages/nostr-fetch/src/testutil/fakedFetcher.ts
@@ -1,5 +1,4 @@
 import { Channel } from "@nostr-fetch/kernel/channel";
-import { verifyEventSig } from "@nostr-fetch/kernel/crypto";
 import type {
   EnsureRelaysOptions,
   FetchTillEoseOptions,
@@ -177,7 +176,7 @@ class FakeFetcherBackend implements NostrFetcherBackend {
 
     const [tx, iter] = Channel.make<NostrEvent>();
     const onEvent = (ev: NostrEvent) => {
-      if (options.skipVerification || verifyEventSig(ev)) {
+      if (options.skipVerification || options.eventVerifier(ev)) {
         tx.send(ev);
       }
     };