allow get block in event handling

src/eventProcessor.ts

@@ -12,6 +12,8 @@ import { AsyncEventEmitter } from "@/asyncEventEmitter";
 import { Indexer, IndexerEvents } from "@/indexer";
 import { EventHandler } from "@/types";
 import { SubscriptionStore } from "./subscriptionStore";
+import { Cache } from "@/cache";
+import { RpcClient } from "@/rpc";
 
 export async function processEvents<
   TAbis extends Record<string, Abi>,
@@ -30,6 +32,8 @@ export async function processEvents<
   readContract: Indexer<TAbis, TContext>["readContract"];
   subscribeToContract: Indexer<TAbis, TContext>["subscribeToContract"];
   unsubscribeFromContract: Indexer<TAbis, TContext>["unsubscribeFromContract"];
+  cache: Cache | null;
+  rpcClient: RpcClient;
 }) {
   const {
     chainId,
@@ -43,6 +47,8 @@ export async function processEvents<
     subscriptionStore,
     subscribeToContract,
     unsubscribeFromContract,
+    cache,
+    rpcClient,
   } = args;
 
   const subscriptionCount = subscriptions.size;
@@ -85,6 +91,38 @@ export async function processEvents<
       unsubscribeFromContract: (opts) => {
         return unsubscribeFromContract(opts);
       },
+      getBlock: async () => {
+        const cachedBlock = await cache?.getBlockByNumber({
+          chainId: chainId,
+          blockNumber: event.blockNumber,
+        });
+
+        if (cachedBlock) {
+          return cachedBlock;
+        }
+
+        const rpcBlock = await rpcClient.getBlockByNumber({
+          number: event.blockNumber,
+        });
+
+        // should not happen
+        if (!rpcBlock) {
+          throw new Error(`Block ${event.blockNumber} not found`);
+        }
+
+        const block = {
+          chainId: chainId,
+          blockNumber: event.blockNumber,
+          blockHash: rpcBlock.hash,
+          timestamp: rpcBlock.timestamp,
+        };
+
+        if (cache) {
+          await cache?.insertBlock(block);
+        }
+
+        return block;
+      },
       subscribeToContract: (opts) => {
         return subscribeToContract({
           ...opts,

src/indexer.ts

@@ -237,6 +237,8 @@ export function createIndexer<
           readContract: readContract,
           subscribeToContract: subscribeToContract,
           unsubscribeFromContract,
+          cache,
+          rpcClient,
         });
 
       for (const id of subscriptionIds) {

src/types.ts

@@ -7,6 +7,7 @@ import {
   ExtractAbiFunctionNames,
 } from "abitype";
 import { Address, GetEventArgs } from "viem";
+import { Block } from "@/cache";
 
 export type Hex = `0x${string}`;
 export type ToBlock = "latest" | bigint;
@@ -83,6 +84,8 @@ export type EventHandlerArgs<
       address: Address;
     }
   ): void;
+
+  getBlock(this: void): Promise<Block>;
 };
 
 export type EventHandler<