better-auth-siws

import bs58 from "bs58"; import { buildSiwsMessage } from "better-auth-siws"; import { createAuthClient } from "better-auth/client"; import { siwsClientPlugin } from "better-auth-siws/client"; // 1. Initialize Better Auth client with SIWS plugin export const clientAuth = createAuthClient({ baseURL: "https://app.example.com/api/auth", // Ensure this matches your server's baseURL plugins: [siwsClientPlugin()], }); /** * Simulates a Solana wallet with publicKey and signMessage capabilities. * In a real app, this would come from a wallet adapter (e.g., @solana/wallet-adapter). */ const mockWallet = { publicKey: { toBase58: () => 'HbC8N9p6jR8g7A6y5X4Z3W2V1U0T9S8Q' }, signMessage: async (data: Uint8Array) => { // In a real app, this would prompt the user to sign // For this example, returning a dummy signature console.log("Wallet signing message:", new TextDecoder().decode(data)); return new Uint8Array(Array(64).fill(0)); // Dummy 64-byte signature } }; async function signInWithSolana(wallet: typeof mockWallet) { // 2. Request a nonce from the server const address = wallet.publicKey.toBase58(); const { nonce, domain, uri } = await clientAuth.api.start({ body: { address }, }); // 3. Build the canonical SIWS message for signing const message = buildSiwsMessage({ domain, address, uri, nonce, issuedAt: new Date().toISOString(), }); // 4. Have the user's wallet sign the message const signatureBytes = await wallet.signMessage(new TextEncoder().encode(message)); const signature = bs58.encode(signatureBytes); // 5. Send signed message and signature to the server for verification const result = await clientAuth.api.verify({ body: { address, message, signature }, }); console.log("Sign-In successful!"); console.log("User session:", result); return result; } // Example usage: signInWithSolana(mockWallet).catch(console.error);