[Qt-qml] NetworkAccessManager

[Jack Wootton]

To follow up on this.  I have been reading the documentation for
QNetworkProxyFactory:
http://doc.qt.nokia.com/4.7-snapshot/qnetworkproxyfactory.html

For the method

QList<QNetworkProxy> QNetworkProxyFactory::systemProxyForQuery ( const
QNetworkProxyQuery & query = QNetworkProxyQuery() )   [static]

it is documented that: "On Windows, this function will use the WinHTTP DLL
functions. Despite its name, Microsoft suggests using it for all
applications that require network connections, not just HTTP. This will
respect the proxy settings set on the registry with the proxycfg.exe tool.
If those settings are not found, this function will attempt to obtain
Internet Explorer's settings and use them."

I'm have set my proxy using proxycfg tool on Windows, however I still get no
proxy results from QNetworkProxyFactory::systemProxyForQuery



On Tue, Apr 27, 2010 at 2:35 PM, Jack Wootton <jackwootton at gmail.com> wrote:

> Hello,
>
> I have modifed the my implementation of
> QDeclarativeNetworkAccessManagerFactory (question follows code) :)
>
> MyNetworkAccessManagerFactory.h
> ===========================
> class MyNetworkAccessManagerFactory : public
> QDeclarativeNetworkAccessManagerFactory
> {
> public:
>      MyNetworkAccessManagerFactory();
>      ~MyNetworkAccessManagerFactory();
>
> public:
>     QNetworkAccessManager* create ( QObject * parent );
> };
>
>
> MyNetworkAccessManagerFactory.cpp
> =============================
> MyNetworkAccessManagerFactory::MyNetworkAccessManagerFactory()
> {
> }
>
> MyNetworkAccessManagerFactory::~MyNetworkAccessManagerFactory()
>
> {
> }
>
> QNetworkAccessManager* MyNetworkAccessManagerFactory::create ( QObject*
> parent )
> {
>      QNetworkProxy proxy;
>      proxy.setHostName("my.proxy.com");
>
>      proxy.setPort(3128);
>
>      // Is this static method call acceptable for a re-entrant method?
>      // QNetworkProxy::setApplicationProxy(proxy);
>
>      QNetworkAccessManager* nam = new QNetworkAccessManager(parent);
>
>
>      nam->setProxy(proxy);
>      return nam;
> }
>
>
>
> I have a question about ensuring the method create(QObject* parent) is
> thread safe / re-entrant: I assumed the method call
> 'QNetworkProxy::setApplicationProxy(proxy);' is not ok since it is static
> and should not be called from a re-entrant function.  Is this the case?  If
> so, is it a problem that it is not called?
>
> I made the changes, but I still don't see the webpage loaded in the QML
> document, but I'll deal with that after I know my code is correct first :)
>
>
>
> On Tue, Apr 27, 2010 at 2:19 AM, Martin Jones <martin.jones at nokia.com>wrote:
>
>> On Tue, 27 Apr 2010 01:18:56 am ext Jack Wootton wrote:
>> > Hi,
>> >
>> > I'm trying to set some proxy settings for a QML application - it's not
>> > working as expected.  I'm unsure the API is being used correctly, can
>> > someone check my code makes sense? There are 3 files: main.cpp,
>> > MyNetworkAccessManagerFactory.h and MyNetworkAccessManagerFactory.cpp
>> >
>> > I'm using qt 4.7 and followed the documentation
>> > (
>> http://doc.qt.nokia.com/4.7-snapshot/qdeclarativenetworkaccessmanagerfact
>> > ory.html) when writing the code.  The method
>> > MyNetworkAccessManagerFactory::create(QObject* parent) does get called
>> > when the QML document is loaded using the QDeclarativeView, so the
>> > framework is definitely picking up the new proxy settings.
>> >
>> > The questions I have are:
>> >
>> > 1. Is the implementation of MyNetworkAccessManagerFactory::create
>> correct?
>> > I assumed because I was subclassing from a class with 'factory' in its
>> > name, that it was ok to return the same pointer to NetworkAccessManager.
>>
>> > 2. How do I know if the method that calls "create" takes ownership of
>> the
>> > returned pointer or not?  I assumed it didn't, hence cleaning up in
>> > ~MyNetworkAccessManagerFactory();
>> >
>> > 3. Is there anything obviously wrong with the way I'm using the
>> > NetworkAccessManager?
>>
>> The factory must create a  new NAM each time it is called.  This is
>> because
>> QML creates multiple threads and each must have its own NAM.  It is
>> important
>> that you set the parent of the NAM created to the parent passed in the
>> create() method (which you already do).  The NAM will be destroyed when
>> its
>> parent is destroyed.  I will update the documentation to make this clear.
>>
>> Also take special note of this line from the documentation:
>>
>> "Note: the create() method may be called by multiple threads, so ensure
>> the
>> implementation of this method is reentrant."
>>
>> --
>> Martin
>>
>
>
>
> --
> Regards
> Jack
>



-- 
Regards
Jack
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