QQmlNetworkAccessManagerFactory Class

The QQmlNetworkAccessManagerFactory class creates QNetworkAccessManager instances for a QML engine. 更多...

头：	#include <QQmlNetworkAccessManagerFactory>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Qml) target_link_libraries(mytarget PRIVATE Qt6::Qml)
qmake:	QT += qml

所有成员列表，包括继承成员

公共函数

virtual	~QQmlNetworkAccessManagerFactory ()
virtual QNetworkAccessManager *	create (QObject * parent ) = 0

详细描述

A QML engine uses QNetworkAccessManager for all network access. By implementing a factory, it is possible to provide the QML engine with custom QNetworkAccessManager instances with specialized caching, proxy and cookies support.

The QNetworkDiskCache can be used as a request cache with QNetworkDiskCache .
使用 QNetworkProxy , traffic sent by the QNetworkAccessManager can be tunnelled through a proxy.
Cookies can be saved for future requests by adding a QNetworkCookieJar .

To implement a factory, subclass QQmlNetworkAccessManagerFactory and implement the virtual create () method, then assign it to the relevant QML engine using QQmlEngine::setNetworkAccessManagerFactory (). For instance, the QNetworkAccessManager objects created by the following snippet will cache requests.

class CachingNetworkAccessManagerFactory : public QQmlNetworkAccessManagerFactory
{
public:
    inline QNetworkAccessManager *create(QObject *parent) override
    {
        QNetworkAccessManager *networkAccessManager = new QNetworkAccessManager(parent);
        QNetworkDiskCache *diskCache = new QNetworkDiskCache(parent);
        diskCache->setCacheDirectory("requestCache");
        networkAccessManager->setCache(diskCache);
        return networkAccessManager;
    }
};

The factory can then be passed to the QML engine so it can instantiate the QNetworkAccessManager with the custom behavior.

CachingNetworkAccessManagerFactory networkManagerFactory;
engine->setNetworkAccessManagerFactory(&networkManagerFactory);

Note the QML engine may create QNetworkAccessManager instances from multiple threads. Because of this, the implementation of the create () method must be 可重入 . In addition, the developer should be careful if the signals of the object to be returned from create () are connected to the slots of an object that may be created in a different thread:

The QML engine internally handles all requests, and cleans up any QNetworkReply objects it creates. Receiving the QNetworkAccessManager::finished () signal in another thread may not provide the receiver with a valid reply object if it has already been deleted.
Authentication details provided to QNetworkAccessManager::authenticationRequired () must be provided immediately, so this signal cannot be connected as a Qt::QueuedConnection (or as the default Qt::AutoConnection from another thread).

For more information about signals and threads, see 线程和 QObject and 信号和槽跨线程 .

另请参阅 QNetworkDiskCache .

成员函数文档编制

`[virtual noexcept]` QQmlNetworkAccessManagerFactory:: ~QQmlNetworkAccessManagerFactory ()

Destroys the factory. The default implementation does nothing.

`[pure virtual]` QNetworkAccessManager QQmlNetworkAccessManagerFactory:: create ( QObject parent )

Creates and returns a network access manager with the specified parent . This method must return a new QNetworkAccessManager instance each time it is called.

Note: this method may be called by multiple threads, so ensure the implementation of this method is reentrant.