Add eth_call API handler

packages/util/src/eth-rpc-handlers.ts

@@ -13,7 +13,49 @@ export const createEthRPCHandlers = async (
     },
 
     eth_call: async (args: any, callback: any) => {
-      // TODO: Implement
+      // TODO: Handle empty args
+      // TODO: Set errors in response
+      // TODO: Parse blockTag
+
+      const { to, data, blockTag } = args[0];
+
+      // For values other than blockHash, resolve value from block_progress table
+      const latestBlock = await indexer.getLatestCanonicalBlock();
+      const blockHash = latestBlock?.blockHash;
+
+      const watchedContract = indexer.getWatchedContracts().find(contract => contract.address === to);
+      if (!watchedContract) {
+        throw new Error('Contract not recognized');
+      }
+
+      if (!indexer.contractMap) {
+        throw new Error('Contract map not found');
+      }
+
+      const contractInterface = indexer.contractMap.get(watchedContract.kind);
+      if (!contractInterface) {
+        throw new Error('Contract ABI not found');
+      }
+
+      // Slice out method signature
+      const functionSelector = data.slice(0, 10);
+
+      // Find the matching function from the ABI
+      const functionFragment = contractInterface.getFunction(functionSelector);
+      if (!functionFragment) {
+        throw new Error('Method not found');
+      }
+
+      // Decode the data based on the matched function
+      const decodedData = contractInterface.decodeFunctionData(functionFragment, data);
+
+      const functionName = functionFragment.name;
+      const indexerMethod = (indexer as any)[functionName].bind(indexer);
+      if (indexerMethod && typeof indexerMethod === 'function') {
+        const result = await indexerMethod(blockHash, to, ...decodedData);
+        const encodedResult = contractInterface.encodeFunctionResult(functionFragment, [result.value]);
+        callback(null, encodedResult);
+      }
     },
 
     eth_getLogs: async (args: any, callback: any) => {

packages/util/src/types.ts

@@ -3,7 +3,7 @@
 //
 
 import { Connection, DeepPartial, EntityTarget, FindConditions, FindManyOptions, ObjectLiteral, QueryRunner } from 'typeorm';
-import { Transaction } from 'ethers';
+import { ethers, Transaction } from 'ethers';
 
 import { MappingKey, StorageLayout } from '@cerc-io/solidity-mapper';
 
@@ -161,6 +161,7 @@ export interface IndexerInterface {
   readonly serverConfig: ServerConfig
   readonly upstreamConfig: UpstreamConfig
   readonly storageLayoutMap: Map<string, StorageLayout>
+  readonly contractMap: Map<string, ethers.utils.Interface>
   // eslint-disable-next-line no-use-before-define
   readonly graphWatcher?: GraphWatcherInterface
   init (): Promise<void>