Add support for Sourcify contract information lookup

- Contract name, ABI and creation transaction hash (start block)
- Runs before the registry lookup and replaces default values (not interactive)
- Non-functional yet as the `chainId` is required which is missing from the registry

Author: 0237h

packages/cli/src/command-helpers/contracts.ts

@@ -151,6 +151,56 @@ export class ContractService {
     throw new Error(`Failed to fetch contract name for ${address}`);
   }
 
+  async getFromSourcify(
+    ABICtor: typeof ABI,
+    networkId: string,
+    address: string,
+  ): Promise<{ abi: ABI; startBlock: string; name: string; } | null> {
+    try {
+      const network = this.registry.getNetworkById(networkId);
+      if (!network) {
+        throw new Error(`Invalid network ${networkId}`);
+      }
+
+      const url = `https://sourcify.dev/server/files/any/${network.chainId}/${address}`; // chainId currently missing from registry
+
+      const json:
+        | {
+          status: string;
+          files: { name: string; path: string; content: string; }[];
+        }
+        | { error: string; } = await (
+          await fetch(url).catch(error => {
+            throw new Error(`Sourcify API is unreachable: ${error}`);
+          })
+        ).json();
+
+      if (json) {
+        if ('error' in json) throw new Error(`Sourcify API error: ${json.error}`);
+
+        let metadata: any = json.files.find(e => e.name === 'metadata.json')?.content;
+        if (!metadata) throw new Error('Contract is missing metadata');
+
+        const tx_hash = json.files.find(e => e.name === 'creator-tx-hash.txt')?.content;
+        if (!tx_hash) throw new Error('Contract is missing tx creation hash');
+
+        const contractName = Object.values(metadata.settings.compilationTarget)[0] as string;
+        metadata = JSON.parse(metadata);
+        return {
+          abi: new ABICtor(contractName, undefined, immutable.fromJS(metadata.output.abi)) as ABI,
+          startBlock: await this.fetchTransactionByHash(networkId, tx_hash),
+          name: contractName,
+        };
+      }
+
+      throw new Error(`No result: ${JSON.stringify(json)}`);
+    } catch (error) {
+      logger(`Failed to fetch from Sourcify: ${error}`);
+    }
+
+    return null;
+  }
+
   private async fetchTransactionByHash(networkId: string, txHash: string) {
     const urls = this.getRpcUrls(networkId);
     if (!urls.length) {

packages/cli/src/commands/add.ts

@@ -80,12 +80,24 @@ export default class AddCommand extends Command {
     if (isLocalHost) this.warn('`localhost` network detected, prompting user for inputs');
     const registry = await loadRegistry();
     const contractService = new ContractService(registry);
+    const sourcifyContractInfo = await contractService.getFromSourcify(
+      EthereumABI,
+      network,
+      address,
+    );
 
     let startBlock = startBlockFlag ? parseInt(startBlockFlag).toString() : startBlockFlag;
     let contractName = contractNameFlag || DEFAULT_CONTRACT_NAME;
-
     let ethabi = null;
-    if (abi) {
+
+    if (sourcifyContractInfo) {
+      startBlock ??= sourcifyContractInfo.startBlock;
+      contractName =
+        contractName == DEFAULT_CONTRACT_NAME ? sourcifyContractInfo.name : contractName;
+      ethabi ??= sourcifyContractInfo.abi;
+    }
+
+    if (!ethabi && abi) {
       ethabi = EthereumABI.load(contractName, abi);
     } else {
       try {

packages/cli/src/commands/init.ts

@@ -2,6 +2,7 @@ import fs from 'node:fs';
 import os from 'node:os';
 import path from 'node:path';
 import { filesystem, print, prompt, system } from 'gluegun';
+import immutable from 'immutable';
 import { Args, Command, Flags } from '@oclif/core';
 import { Network } from '@pinax/graph-networks-registry';
 import { appendApiVersionForGraph } from '../command-helpers/compiler.js';
@@ -200,6 +201,11 @@ export default class InitCommand extends Command {
     if ((fromContract || spkgPath) && protocol && subgraphName && directory && network && node) {
       const registry = await loadRegistry();
       const contractService = new ContractService(registry);
+      const sourcifyContractInfo = await contractService.getFromSourcify(
+        EthereumABI,
+        network,
+        fromContract!,
+      );
 
       if (!protocolChoices.includes(protocol as ProtocolName)) {
         this.error(
@@ -222,7 +228,13 @@ export default class InitCommand extends Command {
           }
         } else {
           try {
-            abi = await contractService.getABI(ABI, network, fromContract!);
+            abi = sourcifyContractInfo
+              ? new EthereumABI(
+                  DEFAULT_CONTRACT_NAME,
+                  undefined,
+                  immutable.fromJS(sourcifyContractInfo.abi),
+                )
+              : await contractService.getABI(ABI, network, fromContract!);
           } catch (e) {
             this.exit(1);
           }
@@ -448,7 +460,7 @@ async function processInitForm(
       ];
     };
 
-    let network = networks[0];
+    let network: Network = networks[0];
     let protocolInstance: Protocol = new Protocol('ethereum');
     let isComposedSubgraph = false;
     let isSubstreams = false;
@@ -611,6 +623,17 @@ async function processInitForm(
           return address;
         }
 
+        const sourcifyContractInfo = await contractService.getFromSourcify(
+          EthereumABI,
+          network.id,
+          address,
+        );
+        if (sourcifyContractInfo) {
+          initStartBlock ??= sourcifyContractInfo.startBlock;
+          initContractName ??= sourcifyContractInfo.name;
+          initAbi ??= sourcifyContractInfo.abi;
+        }
+
         // If ABI is not provided, try to fetch it from Etherscan API
         if (protocolInstance.hasABIs() && !initAbi) {
           abiFromApi = await retryWithPrompt(() =>