Transaction Plans

{
  "feeLimits": [
    {
      "asset": { "mint": "QUOTE_MINT", "tokenProgram": "QUOTE_TOKEN_PROGRAM" },
      "basisPoints": 50,
      "maximumFeeRaw": "1000000"
    }
  ]
}

import { createHash } from "node:crypto";
import { Connection, Keypair, VersionedTransaction } from "@solana/web3.js";
import bs58 from "bs58";

type Stage = {
    format: "v0" | "v1";
    encoding: "base64";
    transaction: string;
    messageSha256: string;
    lifetime: { blockhash: string; lastValidBlockHeight: string };
};

async function sendV0Stage(connection: Connection, stage: Stage, signer: Keypair) {
    if (stage.format !== "v0" || stage.encoding !== "base64") {
        throw new Error("This helper supports base64 v0 stages only");
    }
    const transaction = VersionedTransaction.deserialize(Buffer.from(stage.transaction, "base64"));
    const hash = createHash("sha256").update(transaction.message.serialize()).digest("hex");
    if (hash !== stage.messageSha256 || transaction.message.recentBlockhash !== stage.lifetime.blockhash) {
        throw new Error("Stage message or lifetime mismatch");
    }
    const lastValidBlockHeight = Number(stage.lifetime.lastValidBlockHeight);
    if (!Number.isSafeInteger(lastValidBlockHeight) || lastValidBlockHeight < 0) {
        throw new Error("Invalid blockhash lifetime");
    }
    if (await connection.getBlockHeight("confirmed") > lastValidBlockHeight) {
        throw new Error("Expired stage: reconcile previous submissions before rebuilding");
    }

    transaction.sign([signer]); // Retains signatures from other signers.
    if (transaction.signatures.some((signature) => signature.every((byte) => byte === 0))) {
        throw new Error("Additional wallet signatures are required");
    }
    const signature = bs58.encode(transaction.signatures[0]);
    // Persist this signature with the request and stage ID before network submission.
    console.log("Submitting:", signature);
    await connection.sendRawTransaction(transaction.serialize(), {
        skipPreflight: false,
        preflightCommitment: "confirmed",
    });
    const result = await connection.confirmTransaction({
        signature,
        blockhash: stage.lifetime.blockhash,
        lastValidBlockHeight,
    }, "confirmed");
    if (result.value.err) {
        throw new Error(`Transaction failed: ${JSON.stringify(result.value.err)}`);
    }
    return signature;
}