Function gettxoutproof

src/rpc/rawtransaction.cpp:206–298

}

static UniValue gettxoutproof(const JSONRPCRequest& request)
{
    if (request.fHelp || (request.params.size() != 1 && request.params.size() != 2))
        throw std::runtime_error(
            "gettxoutproof [\"txid\",...] ( blockhash )\n"
            "\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"
            "\nArguments:\n"
            "1. \"txids\"       (string) A json array of txids to filter\n"
            "    [\n"
            "      \"txid\"     (string) A transaction hash\n"
            "      ,...\n"
            "    ]\n"
            "2. \"blockhash\"   (string, optional) If specified, looks for txid in the block with this hash\n"
            "\nResult:\n"
            "\"data\"           (string) A string that is a serialized, hex-encoded data for the proof.\n"
        );

    std::set<uint256> setTxids;
    uint256 oneTxid;
    UniValue txids = request.params[0].get_array();
    for (unsigned int idx = 0; idx < txids.size(); idx++) {
        const UniValue& txid = txids[idx];
        if (txid.get_str().length() != 64 || !IsHex(txid.get_str()))
            throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid txid ")+txid.get_str());
        uint256 hash(uint256S(txid.get_str()));
        if (setTxids.count(hash))
            throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid parameter, duplicated txid: ")+txid.get_str());
       setTxids.insert(hash);
       oneTxid = hash;
    }

    CBlockIndex* pblockindex = nullptr;
    uint256 hashBlock;
    if (!request.params[1].isNull()) {
        LOCK(cs_main);
        hashBlock = uint256S(request.params[1].get_str());
        pblockindex = LookupBlockIndex(hashBlock);
        if (!pblockindex) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
        }
    } else {
        LOCK(cs_main);

        // 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(*pcoinsTip, tx);
            if (!coin.IsSpent()) {
                pblockindex = chainActive[coin.nHeight];
                break;
            }
        }
    }