Fetch Signers - Backend

📘

Related API: List signers

Prerequisites

1. Node.js Installed
   Ensure you have Nodejs installed on your system. You can download it from Node.js' official website.

2. API Key and Mnemonic
   Obtain an API key from the dev portal
   Ensure you have a valid Ethereum mnemonic phrase of the account with a signer associated with the above API key.

3. Dependencies Installed

   Install the required packages:

   Shell

   yarn add siwe viem @neynar/nodejs-sdk
   

Code Breakdown and Steps

1. Import Required Libraries
   The code begins by importing the necessary libraries:

   JavaScript

   import { SiweMessage } from "siwe";
   import { mnemonicToAccount } from "viem/accounts";
   import { NeynarAPIClient, Configuration } from "@neynar/nodejs-sdk";
   

2. Define Your Mnemonic
   Replace "YOUR_MNEMONIC_HERE" with your Ethereum mnemonic phrase:

   JavaScript

   const mnemonic = "YOUR_MNEMONIC_HERE";
   

3. Convert Mnemonic to Account
   The mnemonicToAccount function converts your mnemonic into an account object:

   JavaScript

   const account = mnemonicToAccount(mnemonic);
   

4. Configure Neynar API Client
   Replace "YOUR_API_KEY_HERE" with your API key and set the correct base path for the Neynar API:

   JavaScript

   const config = new Configuration({
     apiKey: "YOUR_API_KEY_HERE",
   });
   
   const client = new NeynarAPIClient(config);
   

5. Create the SIWE Message
   The createSiweMessage function generates a SIWE message with details such as domain, address, and nonce:

   JavaScript

   async function createSiweMessage(address, statement) {
     const { nonce } = await client.fetchNonce();
   
     const message = new SiweMessage({
       scheme: "http",
       domain: "localhost:8080",
       address,
       statement,
       uri: "http://localhost:8080",
       version: "1",
       chainId: "1",
       nonce: nonce,
     });
   
     return message.prepareMessage();
   }
   

6. Sign and Verify the Message
   The fetchSigners function handles the signing process and fetches signers:

   Note: The address should be the custody_address of the farcaster account (Check custody_address here)

   
   
   JavaScript

   async function fetchSigners() {
     const address = account.address;
   
     let message = await createSiweMessage(
       address,
       "Sign in with Ethereum to the app."
     );
   
     const signature = await account.signMessage({ message });
   
     const { signers } = await client.fetchSigners({ message, signature });
   
     return signers;
   }
   

7. Execute the Function
   Call the fetchSigners function and handle success or errors:

   JavaScript

   fetchSigners()
     .then((signers) => {
       console.log("\n\nsigners:", signers, "\n\n");
     })
     .catch((error) => {
       console.error("error:", error);
     });
   

Expected Output

[
  {
    "object": "signer",
    "signer_uuid": "19d0c5fd-9b33-4a48-a0e2-bc7b0555baec",
    "public_key": "0xe4abc135d40f8a6ee216d1a6f2f4e82476dff75f71ea53c5bdebca43f5c415b7",
    "status": "approved",
    "fid": 0
  },
  {
    "object": "signer",
    "signer_uuid": "08c71152-c552-42e7-b094-f510ff44e9cb",
    "public_key": "0xe4cd577123def73295dd9991c589b59b48cdc976b5e83a9ad8d2a13fcfcc0e72",
    "status": "approved",
    "fid": 0
  }
]

For additional help, feel free to contact us.