Method WriteReply

src/httpserver.cpp:515–628

}

void HTTPRequest::WriteReply(HTTPStatusCode status, std::span<const std::byte> reply_body)
{
    HTTPResponse res;

    // Some response headers are determined in advance and stored in the request
    res.m_headers = std::move(m_response_headers);

    // Response version matches request version
    res.m_version = m_version;

    // Add response code
    res.m_status = status;

    // See libevent evhttp_response_needs_body()
    // Response headers are different if no body is needed
    bool needs_body{status != HTTP_NO_CONTENT && (status < 100 || status >= 200)};
    bool needs_content_length{false};

    bool keep_alive{false};

    // See libevent evhttp_make_header_response()
    // Expected response headers depend on protocol version
    if (m_version.major == 1) {
        // HTTP/1.0
        if (m_version.minor == 0) {
            auto connection_header{m_headers.FindFirst("Connection")};
            if (connection_header && ToLower(connection_header.value()) == "keep-alive") {
                res.m_headers.Write("Connection", "keep-alive");
                keep_alive = true;
                // HTTP/1.0 connections are closed by default so EOF is sufficient
                // to indicate end of the body. Adding Content-Length a special case.
                if (needs_body) needs_content_length = true;
            }
        }

        // HTTP/1.1
        if (m_version.minor >= 1) {
            const int64_t now_seconds{TicksSinceEpoch<std::chrono::seconds>(NodeClock::now())};
            res.m_headers.Write("Date", FormatRFC1123DateTime(now_seconds));

            // HTTP/1.1 connections are kept alive by default and always require Content-Length.
            if (needs_body) needs_content_length = true;

            // Default for HTTP/1.1
            keep_alive = true;
        }
    }

    if (needs_content_length) {
        res.m_headers.Write("Content-Length", util::ToString(reply_body.size()));
    }

    if (needs_body && !res.m_headers.FindFirst("Content-Type")) {
        // Default type from libevent evhttp_new_object()
        res.m_headers.Write("Content-Type", "text/html; charset=ISO-8859-1");
    }

    auto connection_header{m_headers.FindFirst("Connection")};