feat(farcaster): enable offchain resolver to farcaster names #194

package.json

@@ -37,6 +37,7 @@
     "eslint": "^6.7.2",
     "express": "^4.17.1",
     "jsdom": "^19.0.0",
+    "node-fetch": "^3.3.2",
     "nodemon": "^2.0.7",
     "redis": "^4.6.10",
     "sharp": "^0.30.1",

src/addressResolvers/farcaster.ts

@@ -0,0 +1,107 @@
+import { capture } from '@snapshot-labs/snapshot-sentry';
+import { graphQlCall, Address, Handle, FetchError, isSilencedError, isEvmAddress } from './utils';
+
+export const NAME = 'Farcaster';
+const FNAMES_API_URL = 'https://fnames.farcaster.xyz/transfers?name=';
+const NEYNAR_API_URL = 'https://api.neynar.com/v2/farcaster/user/';
+const API_KEY = process.env.NEYNAR_API_KEY ?? '';
+
+
+interface UserDetails {
+  username: string;
+  verified_addresses: {
+    eth_addresses: string[];
+    sol_addresses: string[];
+  };
+  pfp_url: string;
+}
+
+interface ApiResponse {
+  [address: string]: UserDetails[];
+}
+
+interface UserResult {
+  username?: string;
+  eth_addresses?: string[];
+  sol_addresses?: string[];
+  pfp_url?: string;
+}
+
+
+async function fetchData<T>(url: string, method: string = 'GET'): Promise<T> {
+  const headers = {
+    Accept: 'application/json',
+    api_key: API_KEY
+  };
+  const response = await fetch(url, { method, headers });
+  if (!response.ok) {
+    throw new Error(`Failed to fetch data from the API. Status: ${response.status}`);
+  }
+  return response.json() as Promise<T>;
+}
+
+export async function lookupAddresses(
+  addresses: string[]
+): Promise<{ [key: string]: UserResult | string }> {
+  const results: { [key: string]: UserResult | string } = {};
+  try {
+    const addressesQuery = addresses.join(',');
+    const url = `${NEYNAR_API_URL}bulk-by-address?addresses=${addressesQuery}`;
+    const userDetails = await fetchData<ApiResponse>(url);
+
+    for (const [address, data] of Object.entries(userDetails)) {
+      if (Array.isArray(data) && data.length > 0) {
+        const {
+          username,
+          verified_addresses: { eth_addresses = [], sol_addresses = [] },
+          pfp_url
+        } = data[0];
+        results[address] = { username, eth_addresses, sol_addresses, pfp_url };
+      } else {
+        results[address] = 'No user found for this address.';
+      }
+    }
+  } catch (error) {
+    console.error(`Error fetching address details:`, error);
+    throw new Error(`Error fetching address details.`);
+  }
+  return results;
+}
+
+async function fetchUserDetailsByUsername(username: string): Promise<UserResult | null> {
+  try {
+    const transferData = await fetchData<{ transfers: any[] }>(`${FNAMES_API_URL}${username}`);
+    if (transferData.transfers.length > 0) {
+      const userDetails = await fetchData<{ result: { users: UserDetails[] } }>(
+        `${NEYNAR_API_URL}search?q=${username}&viewer_fid=197049`
+      );
+      if (userDetails.result && userDetails.result.users.length > 0) {
+        const { username, verified_addresses, pfp_url } = userDetails.result.users[0];
+        return {
+          eth_addresses: verified_addresses.eth_addresses,
+          username
+        };
+      }
+    }
+  } catch (error) {
+    console.error(`Error fetching user details for ${username}:`, error);
+    throw new Error(`Error fetching user details for ${username}.`);
+  }
+  return null;
+}
+
+export async function resolveNames(
+  handles: string[]
+): Promise<{ [handle: string]: UserResult | string }> {
+  const results: { [handle: string]: UserResult | string } = {};
+  for (const handle of handles) {
+    const normalizedHandle = handle.replace('.fcast.id', '');
+    const userDetails = await fetchUserDetailsByUsername(normalizedHandle);
+    if (userDetails) {
+      results[handle] = userDetails;
+    } else {
+      results[handle] = 'User not found or error searching for details.';
+    }
+  }
+  return results;
+}

test/integration/addressResolvers/farcaster.test.ts

@@ -0,0 +1,12 @@
+import { resolveNames, lookupAddresses } from '../../../src/addressResolvers/farcaster';
+import testAddressResolver from './helper';
+
+testAddressResolver({
+  name: 'Farcaster',
+  lookupAddresses,
+  resolveNames,
+  validAddress: '0xd1a8Dd23e356B9fAE27dF5DeF9ea025A602EC81e',
+  validDomain: 'codingsh.fcast.id',
+  blankAddress: '0x0000000000000000000000000000000000000000',
+  invalidDomains: ['domain.crypto', 'domain.eth', 'domain.com']
+});