How to change POST data in qtwebkit?

Question

For change POST variables in qtwebkit need change or replace outgoingData in createRequest(...). How to create own <PyQt4.QtCore.QIODevice object at 0x03BA...> not QFile or QByteArray. Exactly QIODevice object! It is needed for creation of writable device. Or how to convert <PyQt4.QtCore.QBuffer object at 0x03BA...> to <PyQt4.QtCore.QIODevice object at 0x03BA...>.
This device most used in QNetworkAccessManager:
https://qt.gitorious.org/qt/webkit/source/7647fdaf9a4b526581e02fbd0e87c41a96cbfebb:src/network/access/qnetworkaccessmanager.cpp#L941

QNetworkReply *QNetworkAccessManager::createRequest(QNetworkAccessManager::Operation op,
const QNetworkRequest &req,
QIODevice *outgoingData)
...

UPDATE: After call this method:

def createRequest(manager, operation, request, data):
    if data.size() > 0:
        post_body = "q=hello"
        output = QtCore.QByteArray()
        buffer = QtCore.QBuffer(output)
        buffer.open(QtCore.QIODevice.ReadWrite)
        buffer.writeData(post_body)
        data = buffer

    reply = QNetworkAccessManager.createRequest(manager, operation, request, data)
    return reply

script hangs up...

As the documentation will tell you, QIODevice is an abstract class, i.e., you are supposed to subclass it and implement the various methods yourself, rather than directly instantiating it. — mdurant, Oct 29 '14 at 13:37

score 0 · Answer 1 · answered Oct 29 '14 at 13:46

0

If I'm making sense of your question, A QBuffer is already an implementation of the (abstract, as noted by @mdurant) QIODevice class. So for example (I tried this on PySide but I believe PyQt should be the same):

>>> from PySide.QtCore import QIODevice, QBuffer, QByteArray
>>> buff = QBuffer(QByteArray())
>>> isinstance(buff, QIODevice)
True

To create a writable QIODevice writing into a QByteArray, you can do more or less the following:

ba = QByteArray()
buff = QBuffer(ba)
buff.open(QIODevice.WriteOnly)

You can now write to buff as if it was a QIODevice and then the data will be available in ba.

answered Oct 29 '14 at 13:46

shevron

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ba = QByteArray() buff = QBuffer(ba) buff.open(QIODevice.WriteOnly) print buff printing is: `` not`` – user3446100 Oct 29 '14 at 13:56
sorry, i'm update my question, ok in ba but this device not work in `createRequest(QNetworkAccessManager::Operation op, const QNetworkRequest &req, QIODevice *outgoingData)` – user3446100 Oct 29 '14 at 14:36
1

What do you mean by "not work"? Are you getting an error message? BTW would help if you sitck to Python code examples (not C++/Python mix); also there is no need to paste the class `__repr__` string - it would be much more readable if you just wrote `QBuffer` or `PyQt4.QtCore.QBuffer` instead of those horrible `` strings. – shevron Oct 29 '14 at 21:44
I'm again update my question! After call method - `createRequest(manager, operation, request, data)` with **QBuffer** in **data** script hangs up... – user3446100 Oct 29 '14 at 22:19

score 0 · Answer 2 · answered Oct 31 '14 at 08:08

Basically you were close, I wonder why you didn't get a segmentation fault, it happened to me every time when I didn't set the parent object of the new data object:

def createRequest(manager, operation, request, data):
    if data.size() > 0:
        data = QBuffer(QByteArray("q=hello"))
        # data was originally a ReadOnly device as well, keep it that way
        data.open(QIODevice.ReadOnly)

    reply = QNetworkAccessManager.createRequest(manager, operation, request, data)
    # must explicitly set the parent of the newly created data object to this reply object. 
    data.setParent(reply)

    return reply

I wrote about this exact issue here: https://github.com/integricho/path-of-a-pyqter/tree/master/qttut07

How to change POST data in qtwebkit?

2 Answers2

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