feat: add ABI fetcher script for direct and proxy contracts via Filfox API

Author: pali101

packages/synapse-sdk/src/script/abiFetcher.ts

@@ -0,0 +1,94 @@
+import type { Address } from 'viem';
+
+// Define the type for the contract object wagmi uses
+export type ContractConfig = {
+  name: string;
+  address: Address;
+  chainId: number;
+  isProxy?: boolean;
+};
+
+interface FilfoxProxyResponse {
+  proxyImpl: string | null;
+  abi: string | null;
+}
+
+// Unified ABI fetcher: routes to proxy or direct ABI fetch logic based on contract type.
+// If the contract is a proxy (isProxy=true), fetches the implementation ABI; otherwise, fetches the contract's own ABI.
+export async function fetchContractAbi(contract: ContractConfig): Promise<{ body: string }> {
+    if (contract.isProxy) {
+        return fetchProxyAbi(contract);
+    } else {
+        return fetchDirectAbi(contract);
+    }
+}
+
+/**
+ * Fetches the ABI for contract's implementation from Filfox.
+ * @param contract The contract configuration from wagmi.
+ * @returns A promise resolving to the ABI content for wagmi.
+ */
+async function fetchDirectAbi(contract: ContractConfig): Promise<{ body: string }> {
+  return fetchAbiFromAddress(contract.address, contract.name, contract.chainId);
+}
+
+/**
+ * Fetches the ABI for a proxy contract's implementation from Filfox.
+ * @param contract The contract configuration from wagmi.
+ * @returns A promise resolving to the ABI content for wagmi.
+ */
+async function fetchProxyAbi(contract: ContractConfig): Promise<{ body: string }> {
+  // 1. Fetch the implementation address from the proxy contract.
+  const proxyUrl = `https://filfox.info/api/v1/address/${contract.address}/contract`;
+  const proxyResponse = await fetch(proxyUrl, {
+    headers: { 'Accept': 'application/json' },
+  });
+  if (!proxyResponse.ok) {
+    throw new Error(
+      `Failed to fetch data for proxy contract. Status: ${proxyResponse.status}`,
+    );
+  }
+  const proxyData = await proxyResponse.json() as FilfoxProxyResponse;
+  const implementationAddress = proxyData?.proxyImpl;
+  if (!implementationAddress || implementationAddress === "null") {
+    throw new Error(
+      `Could not find implementation address ('proxyImpl') in API response for ${contract.name}.`,
+    );
+  }
+    
+  // 2. Fetch the ABI from the implementation contract using the helper
+  return fetchAbiFromAddress(implementationAddress as Address, contract.name, contract.chainId);
+}
+
+// Internal helper to fetch and parse ABI from Filfox for a given address
+async function fetchAbiFromAddress(address: Address, name: string, chainId: number): Promise<{ body: string }> {
+  try {
+    const url = `https://filfox.info/api/v1/address/${address}/contract`;
+    const response = await fetch(url, {
+      headers: { 'Accept': 'application/json' },
+    });
+    if (!response.ok) {
+      throw new Error(
+        `Failed to fetch data for contract. Status: ${response.status}`,
+      );
+    }
+    const data = await response.json() as FilfoxProxyResponse;
+    const abiString = data?.abi;
+    if (typeof abiString !== 'string' || abiString.length === 0) {
+      throw new Error(
+        `Failed to parse ABI. The '.abi' field may be missing, null, or not a valid string.`
+      );
+    }
+    const abi = JSON.parse(abiString);
+    console.log(`Successfully fetched ABI for ${name}.`);
+    return {
+      body: JSON.stringify(abi, null, 2),
+    };
+  } catch (error) {
+    console.error(
+      `Failed to fetch ABI for ${name} on chain ${chainId}:`,
+      error,
+    );
+    throw error;
+  }
+}