QNetworkAccessManager：从串行QIODevice发布http multipart [英] QNetworkAccessManager: post http multipart from serial QIODevice

问题描述

我正在尝试使用QNetworkAccessManager将http多部分上传到专用服务器。

I'm trying to use QNetworkAccessManager to upload http multiparts to a dedicated server.

multipart包含一个描述正在上传的数据的JSON部分。

The multipart consists of a JSON part describing the data being uploaded.

从串行QIODevice读取数据，该QIODevice对数据进行加密。

The data is read from a serial QIODevice, which encrypts the data.

这是创建多部分请求的代码：

This is the code that creates the multipart request:

QHttpMultiPart *multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);

QHttpPart metaPart;
metaPart.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");
metaPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-data; name=\"metadata\""));
metaPart.setBody(meta.toJson());
multiPart->append(metaPart);

QHttpPart filePart;
filePart.setHeader(QNetworkRequest::ContentTypeHeader, QVariant(fileFormat));
filePart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-data; name=\"file\""));
filePart.setBodyDevice(p_encDevice);
p_encDevice->setParent(multiPart); // we cannot delete the file now, so delete it with the multiPart
multiPart->append(filePart);

QNetworkAccessManager netMgr;
QScopedPointer<QNetworkReply> reply( netMgr.post(request, multiPart) );
multiPart->setParent(reply.data()); // delete the multiPart with the reply

如果p_encDevice是QFile的实例，则该文件上传很好。

If the p_encDevice is an instance of QFile, that file gets uploaded just fine.

如果使用专门的加密QIODevice（串行设备），则从我的自定义设备读取所有数据。但是QNetworkAccessManager :: post（）没有完成（挂起）。

If the specialised encrypting QIODevice is used (serial device) then all of the data is read from my custom device. however QNetworkAccessManager::post() doesn't complete (hangs).

我在 QHttpPart ：

if device是顺序的（例如套接字，但不是文件），
QNetworkAccessManager :: post（）应该在设备有
发出finish（）后调用。

if device is sequential (e.g. sockets, but not files), QNetworkAccessManager::post() should be called after device has emitted finished().

不幸的是我不知道怎么做。

Unfortunately I don't know how do that.

请指教。

编辑：

QIODevice根本没有完成（）插槽。更重要的是，如果没有调用QNetworkAccessManager :: post（），那么从我的自定义IODevice读取根本不会发生，因此设备将无法发出这样的事件。 （赶上22？）

QIODevice doesn't have finished() slot at all. What's more, reading from my custom IODevice doesn't happen at all if QNetworkAccessManager::post() is not called and therefore the device wouldn't be able to emit such an event. (Catch 22?)

编辑2：

似乎QNAM做了根本不适用于顺序设备。请参阅讨论qt-project 。

It seems that QNAM does not work with sequential devices at all. See discussion on qt-project.

编辑3：

我设法欺骗QNAM让它认为它是从非顺序设备读取的，但寻求和重置功能阻止寻求。这将一直有效，直到QNAM实际上试图寻找。

I managed to "fool" QNAM to make it think that it is reading from non-sequential devices, but seek and reset functions prevent seeking. This will work until QNAM will actually try to seek.

bool AesDevice::isSequential() const
{
    return false;
}

bool AesDevice::reset()
{
    if (this->pos() != 0) {
        return false;
    }
    return QIODevice::reset();
}

bool AesDevice::seek(qint64 pos)
{
    if (this->pos() != pos) {
        return false;
    }
    return QIODevice::seek(pos);
}

推荐答案

来自< a href =http://qt-project.org/forums/viewthread/25317/ =nofollow> qt-project 并通过检查源代码，似乎QNAM不能用于顺序一点都不文档和代码都是错误的。

From a separate discussion in qt-project and by inspecting the source code it seems that QNAM doesn't work with sequential at all. Both the documentation and code are wrong.

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