hub-monorepo/packages/hub-nodejs/docs/Utils.md

Utils

Helpers to manage Farcaster Messages.

• Bytes
  • bytesToHexString
  • hexStringToBytes
  • bytesToUTF8String
• Errors
  • HubError
  • HubErrorCodes
• Time
  • getFarcasterTime
  • toFarcasterTime
  • fromFarcasterTime
• Verifications
  • makeVerificationEthAddressClaim

Bytes

Farcaster stores addresses, keys and signatures as binary data held in Uint8Arrays. Converting such values to hex strings or utf-8 strings is useful when calling other libraries or displaying strings to users.

bytesToHexString

Returns a hex string from a bytes array.

Usage

// TODO

Returns

Value	Description
TBD	TBD

Parameters

Name	Type	Description
TBD	TBD	TBD

---

hexStringToBytes

Returns a bytes array from a hex string.

Usage

// TODO

Returns

Value	Description
TBD	TBD

Parameters

Name	Type	Description
TBD	TBD	TBD

---

bytesToUTF8String

Returns a UTF-8 string from a bytes array.

Errors

Error handling in @farcaster/hub-nodejs is monadic and functions do not throw exceptions. Each function call returns a Result object which contains a success value or error value. Read the neverthrow documentation to learn about handling Result types.

Hub Error

TODO

Hub Error Codes

Name	Description
unauthenticated	TODO
unauthorized	TODO
bad_request	TODO
bad_request.parse_failure	TODO
bad_request.invalid_param	TODO
bad_request.validation_failure	TODO
bad_request.duplicate	TODO
bad_request.conflict	TODO
not_found	TODO
not_implemented	TODO
not_implemented.deprecated	TODO
unavailable	TODO
unavailable.network_failure	TODO
unavailable.storage_failure	TODO
unknown	TODO

Time

Farcaster timestamps are counted as milliseconds since the Farcaster epoch, which began on Jan 1, 2021 00:00:00 UTC.

Using a more recent epoch lets Farcaster use shorter 32-bit values to hold times which reduces the size of messages. Timestamps are usually measured as milliseconds since the Unix epoch and can be converted to Farcaster time by subtracting 1609459200000.

getFarcasterTime

Returns the current time in milliseconds as a Farcaster timestamp.

Usage

// TODO

Returns

Value	Description
TBD	TBD

Parameters

Name	Type	Description
TBD	TBD	TBD

---

toFarcasterTime

Converts a Unix milliseconds timestamp to a Farcaster milliseconds timestamp.

Usage

// TODO

Returns

Value	Description
TBD	TBD

Parameters

Name	Type	Description
TBD	TBD	TBD

---

fromFarcasterTime

Converts a Farcaster milliseconds timestamp to a Unix milliseconds timestamp.

Usage

// TODO

Returns

Value	Description
TBD	TBD

Parameters

Name	Type	Description
TBD	TBD	TBD

Verifications

makeVerificationEthAddressClaim

Usage

import {
  Eip712Signer,
  FarcasterNetwork,
  hexStringToBytes,
  makeVerificationEthAddressClaim,
} from '@farcaster/hub-nodejs';
import { ethers } from 'ethers';

// Create a valid Eip712Signer from the Etherum Address making the claim
const mnemonic = 'ordinary long coach bounce thank quit become youth belt pretty diet caught attract melt bargain';
const wallet = ethers.Wallet.fromMnemonic(mnemonic);
const eip712Signer = (await Eip712Signer.fromSigner(wallet))._unsafeUnwrap();

// Construct the claim object with the block number of a recent block
const blockHashHex = '0x1d3b0456c920eb503450c7efdcf9b5cf1f5184bf04e5d8ecbcead188a0d02018';
const blockHashBytes = hexStringToBytes(blockHashHex)._unsafeUnwrap();

const claimResult = makeVerificationEthAddressClaim(1, eip712Signer.signerKey, FarcasterNetwork.DEVNET, blockHashBytes);

claimResult.map((c) => console.log(c));

Returns

Value	Description
TBD	TBD

Parameters

Name	Type	Description
TBD	TBD	TBD