Function getblockfrompeer

src/rpc/blockchain.cpp:875–918

}

static RPCHelpMan getblockfrompeer()
{
    return RPCHelpMan{
        "getblockfrompeer",
        "Attempt to fetch block from a given peer.\n\n"
        "We must have the header for this block, e.g. using submitheader.\n"
        "Subsequent calls for the same block and a new peer will cause the response from the previous peer to be ignored.\n\n"
        "Returns an empty JSON object if the request was successfully scheduled.",
        {
            {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The block hash to try to fetch"},
            {"peer_id", RPCArg::Type::NUM, RPCArg::Optional::NO, "The peer to fetch it from (see getpeerinfo for peer IDs)"},
        },
        RPCResult{RPCResult::Type::OBJ, "", /*optional=*/false, "", {}},
        RPCExamples{
            HelpExampleCli("getblockfrompeer", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\" 0")
            + HelpExampleRpc("getblockfrompeer", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\" 0")
        },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    const NodeContext& node = EnsureAnyNodeContext(request.context);
    ChainstateManager& chainman = EnsureChainman(node);
    PeerManager& peerman = EnsurePeerman(node);

    const uint256& block_hash{ParseHashV(request.params[0], "blockhash")};
    const NodeId peer_id{request.params[1].get_int64()};

    const CBlockIndex* const index = WITH_LOCK(cs_main, return chainman.m_blockman.LookupBlockIndex(block_hash););

    if (!index) {
        throw JSONRPCError(RPC_MISC_ERROR, "Block header missing");
    }

    const bool block_has_data = WITH_LOCK(::cs_main, return index->nStatus & BLOCK_HAVE_DATA);
    if (block_has_data) {
        throw JSONRPCError(RPC_MISC_ERROR, "Block already downloaded");
    }

    if (const auto err{peerman.FetchBlock(peer_id, *index)}) {
        throw JSONRPCError(RPC_MISC_ERROR, err.value());
    }
    return UniValue::VOBJ;
},
    };
}

static RPCHelpMan getblockhash()
{