Function gettxoutproof

src/rpc/rawtransaction.cpp:311–410

}

static RPCHelpMan gettxoutproof()
{
    return RPCHelpMan{"gettxoutproof",
                "\nReturns a hex-encoded proof that \"txid\" was included in a block.\n"
                "\nNOTE: By default this function only works sometimes. This is when there is an\n"
                "unspent output in the utxo for this transaction. To make it always work,\n"
                "you need to maintain a transaction index, using the -txindex command line option or\n"
                "specify the block in which the transaction is included manually (by blockhash).\n",
                {
                    {"txids", RPCArg::Type::ARR, RPCArg::Optional::NO, "The txids to filter",
                        {
                            {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "A transaction hash"},
                        },
                        },
                    {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED_NAMED_ARG, "If specified, looks for txid in the block with this hash"},
                },
                RPCResult{
                    RPCResult::Type::STR, "data", "A string that is a serialized, hex-encoded data for the proof."
                },
                RPCExamples{""},
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    std::set<uint256> setTxids;
    UniValue txids = request.params[0].get_array();
    if (txids.empty()) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Parameter 'txids' cannot be empty");
    }
    for (unsigned int idx = 0; idx < txids.size(); idx++) {
        auto ret = setTxids.insert(ParseHashV(txids[idx], "txid"));
        if (!ret.second) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid parameter, duplicated txid: ") + txids[idx].get_str());
        }
    }

    CBlockIndex* pblockindex = nullptr;
    uint256 hashBlock;
    ChainstateManager& chainman = EnsureAnyChainman(request.context);
    if (!request.params[1].isNull()) {
        LOCK(cs_main);
        hashBlock = ParseHashV(request.params[1], "blockhash");
        pblockindex = chainman.m_blockman.LookupBlockIndex(hashBlock);
        if (!pblockindex) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
        }
    } else {
        LOCK(cs_main);
        CChainState& active_chainstate = chainman.ActiveChainstate();

        // Loop through txids and try to find which block they're in. Exit loop once a block is found.
        for (const auto& tx : setTxids) {
            const Coin& coin = AccessByTxid(active_chainstate.CoinsTip(), tx);
            if (!coin.IsSpent()) {
                pblockindex = active_chainstate.m_chain[coin.nHeight];
                break;
            }
        }
    }