摩擦がなく安全なUX：数百万人のユーザーをSolanaへ導く技術スタック

import { PrivyClient } from '@privy-io/server-sdk';

// Initialize the Privy client
const privy = new PrivyClient({
  apiKey: process.env.PRIVY_API_KEY
});

// Create a new Solana managed wallet
async function createFeePayerWallet() {
  const { id, address, chainType } = await privy.walletApi.create({
    chainType: 'solana',
    policyIds: ['optional_policy_id'],
    idempotencyKey: 'unique_request_identifier'
  });

  console.log(`Created fee payer wallet with ID: ${id}`);
  console.log(`Wallet address: ${address}`);

  return { id, address };
}

// Make sure to fund this wallet with SOL to cover transaction fees

import { useSolanaWallets } from '@privy-io/react-auth/solana';
import {
  TransactionMessage,
  PublicKey,
  VersionedTransaction,
  Connection
} from '@solana/web3.js';

async function sendGaslessTransaction(instructions) {
  // Get user's embedded wallet
  const { wallets } = useSolanaWallets();
  const embeddedWallet = wallets.find(wallet =>
    wallet.walletClientType === 'privy'
  );

  if (!embeddedWallet) {
    throw new Error('No embedded wallet found');
  }

  // Connect to Solana via Helius for better performance
  const connection = new Connection('https://mainnet.helius-rpc.com/?api-key=YOUR_HELIUS_API_KEY');
  const { blockhash } = await connection.getLatestBlockhash();

  // Set your managed wallet as fee payer
  const feePayerAddress = 'YOUR_PRIVY_SERVER_WALLET_ADDRESS';

  // Build transaction with managed wallet as payer
  const message = new TransactionMessage({
    payerKey: new PublicKey(feePayerAddress),
    recentBlockhash: blockhash,
    instructions
  }).compileToV0Message();

  const transaction = new VersionedTransaction(message);

  // Have user sign the transaction
  const provider = await embeddedWallet.getProvider();
  const serializedMessage = Buffer.from(
    transaction.message.serialize()
  ).toString('base64');

  const { signature } = await provider.request({
    method: 'signMessage',
    params: { message: serializedMessage }
  });

  // Add user signature
  const userSignature = Buffer.from(signature, 'base64');
  transaction.addSignature(
    new PublicKey(embeddedWallet.address),
    userSignature
  );

  // Send to your backend for fee payer signature
  const serializedTx = Buffer.from(
    transaction.serialize()
  ).toString('base64');

  const response = await fetch('/api/sponsor-transaction', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ transaction: serializedTx })
  });

  const { transactionHash } = await response.json();
  return transactionHash;
}

// pages/api/sponsor-transaction.js
import { VersionedTransaction } from '@solana/web3.js';
import { PrivyClient } from '@privy-io/server-sdk';

// Initialize Privy SDK
const privy = new PrivyClient({
  apiKey: process.env.PRIVY_API_KEY
});
// For App Router (Next.js 13+)
export async function POST(request) {
  try {
    const { transaction: serializedTx } = await request.json();

    // Deserialize the transaction to verify it (optional)
    const txBuffer = Buffer.from(serializedTx, 'base64');
    const transaction = VersionedTransaction.deserialize(txBuffer);

    // Verify the transaction (check fee payer, validate against policies)
    // ...verification logic here...

    // Sign AND send with your Privy managed wallet in one step
    const serverWalletId = process.env.PRIVY_SERVER_WALLET_ID;
    const { hash } = await privy.walletApi.solana.signAndSendTransaction({
      walletId: serverWalletId,
      caip2: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1', // Mainnet
      transaction: serializedTx,
      rpcUrl: 'https://mainnet.helius-rpc.com/?api-key=YOUR_HELIUS_API_KEY',
      options: {
        maxRetries: 5,
        skipPreflight: true
      }
    });

    return Response.json({
      transactionHash: hash,
      message: 'Transaction sent successfully'
    }, { status: 200 });
  } catch (error) {
    console.error('Error processing transaction:', error);
    return Response.json({
      error: 'Failed to process transaction',
      details: error.message
    }, { status: 500 });
  }
}