Function rest_headers

src/rest.cpp:180–275

}

static bool rest_headers(const std::any& context,
                         HTTPRequest* req,
                         const std::string& uri_part)
{
    if (!CheckWarmup(req))
        return false;
    std::string param;
    const RESTResponseFormat rf = ParseDataFormat(param, uri_part);
    std::vector<std::string> path = SplitString(param, '/');

    std::string raw_count;
    std::string hashStr;
    if (path.size() == 2) {
        // deprecated path: /rest/headers/<count>/<hash>
        hashStr = path[1];
        raw_count = path[0];
    } else if (path.size() == 1) {
        // new path with query parameter: /rest/headers/<hash>?count=<count>
        hashStr = path[0];
        try {
            raw_count = req->GetQueryParameter("count").value_or("5");
        } catch (const std::runtime_error& e) {
            return RESTERR(req, HTTP_BAD_REQUEST, e.what());
        }
    } else {
        return RESTERR(req, HTTP_BAD_REQUEST, "Invalid URI format. Expected /rest/headers/<hash>.<ext>?count=<count>");
    }

    const auto parsed_count{ToIntegral<size_t>(raw_count)};
    if (!parsed_count.has_value() || *parsed_count < 1 || *parsed_count > MAX_REST_HEADERS_RESULTS) {
        return RESTERR(req, HTTP_BAD_REQUEST, strprintf("Header count is invalid or out of acceptable range (1-%u): %s", MAX_REST_HEADERS_RESULTS, raw_count));
    }

    auto hash{uint256::FromHex(hashStr)};
    if (!hash) {
        return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
    }

    const CBlockIndex* tip = nullptr;
    std::vector<const CBlockIndex*> headers;
    headers.reserve(*parsed_count);
    ChainstateManager* maybe_chainman = GetChainman(context, req);
    if (!maybe_chainman) return false;
    ChainstateManager& chainman = *maybe_chainman;
    {
        LOCK(cs_main);
        CChain& active_chain = chainman.ActiveChain();
        tip = active_chain.Tip();
        const CBlockIndex* pindex{chainman.m_blockman.LookupBlockIndex(*hash)};
        while (pindex != nullptr && active_chain.Contains(*pindex)) {
            headers.push_back(pindex);
            if (headers.size() == *parsed_count) {
                break;
            }
            pindex = active_chain.Next(*pindex);
        }
    }