通过http将文件发送到客户端时丢失连接

Question

我使用poco写了https服务器。有时，当客户端下载文件时，他失去了连接。在客户端，它看起来像是在等待重新连接，并且在很长一段时间后他都会断开连接。在服务器端连接下降速度更快。我增加了超时，但这没有给出好的结果。

我该怎么做，因为客户端可以正常下载文件到最后？

发送文件的代码：

void DownloadHandler::handleRequest(HTTPServerRequest& request, HTTPServerResponse& response)
{
    response.setVersion(HTTPServerResponse::HTTP_1_1);

    QString fileName = "filename.avi";
    QFile file(fileName);
    const int size = 1024*100; char buffer[size] ;

    response.setChunkedTransferEncoding(false);
    response.setContentType("application/file");    

    if(!file.open(QIODevice::ReadOnly)){
        return;
    }   

    std::streamsize length = file.size(), readBefore = 0, readNow = 0;

    response.setContentLength(length);
    std::ostream& ostr = response.send();

    while(readBefore < length) {
        if((readBefore + size) <= length){
            readNow = size;
        }
        else{
            readNow = length - readBefore;
        }

        readBefore += readNow;
        file.read(buffer, readNow);

        if(ostr){
            ostr.write(buffer, readNow);
            ostr.flush();
        }
        else{
            app->printStatus("Error number " + QString::number(response.getStatus()), false, false);
            break;
        }
    }
    file.close();
}

服务器初始化：

Poco::SharedPtr<PrivateKeyPassphraseHandler> pConsoleHandler = new KeyConsoleHandler(true);
        Poco::SharedPtr<InvalidCertificateHandler> pInvalidCertHandler = new ConsoleCertificateHandler(true);
        Context::Ptr pContext = new Context(Context::SERVER_USE, "crypto/mycert.pem", "crypto/mycert.pem", "", Context::VERIFY_ONCE, 9, false, "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH");
        pContext->setSessionTimeout(100);
        SSLManager::instance().initializeServer(pConsoleHandler, pInvalidCertHandler, pContext);

        Poco::Net::HTTPRequestHandlerFactory::Ptr factory (new RequestFactory() );
        Poco::Net::SecureServerSocket socket(20000);
        socket.setReceiveTimeout(Poco::Timespan(1000, 0));
        socket.setSendTimeout(Poco::Timespan(1000, 0));
        socket.setKeepAlive(true);

        Poco::Net::HTTPServerParams::Ptr params(new Poco::Net::HTTPServerParams() ) ;
        params->setKeepAliveTimeout(Poco::Timespan(10, 10));
        params->setTimeout(Poco::Timespan(1000, 10));
        params->setKeepAlive(true);
        params->setServerName("MediaShark:20000");
        params->setSoftwareVersion("1.1");

        Poco::ThreadPool pool(2, 6, 60, 0);
        Poco::Net::HTTPServer server(factory, pool, socket, params);
        server.start(); 

由于