QtWebkit: How to check HTTP status code?
I'm writing a thumbnail generator as per an example in the QtWebkit documentation. I would like to avoid screenshots of error pages such as 404 not found
or 503 Internal ser开发者_JAVA百科ver error
.
However, the QWebPage::loadFinished() signal is always emitted with ok = true
even when the page gives an HTTP error. Is there a way in QtWebkit to check the HTTP status code on a response?
Turns out you need to monitor the QNetworkAccessManager associated with your QWebPage and wait for a finished(...) signal. You can then inspect the HTTP response and check its status code by asking for the QNetworkRequest::HttpStatusCodeAttribute
attribute.
It's better explained in code:
void MyClass::initWebPage()
{
myQWebPage = new QWebPage(this);
connect(
myQWebPage->networkAccessManager(), SIGNAL(finished(QNetworkReply *)),
this, SLOT(httpResponseFinished(QNetworkReply *))
);
}
void MyClass::httpResponseFinished(QNetworkReply * reply)
{
switch (reply->error())
{
case QNetworkReply::NoError:
// No error
return;
case QNetworkReply::ContentNotFoundError:
// 404 Not found
failedUrl = reply->request.url();
httpStatus = reply->attribute(
QNetworkRequest::HttpStatusCodeAttribute).toInt();
httpStatusMessage = reply->attribute(
QNetworkRequest::HttpReasonPhraseAttribute).toByteArray();
break;
}
}
There are more NetworkErrors to choose from, e.g. for TCP errors or HTTP 401.
This is what I'm using in a porting project. It checks the reply and decides to start backing off making request or not. The backing off part is in progress but I left the comments in.
QNetworkReply* reply = qobject_cast<QNetworkReply*>(sender());
Q_CHECK_PTR(reply);
QVariant statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
if (!statusCode.isNull() && statusCode.toInt() >= 400){
//INVALID_SERVER_RESPONSE_BACKOFF;
qDebug() << "server returned invalid response." << reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();
return;
}else if (!statusCode.isNull() && statusCode.toInt() != 200){
//INVALID_SERVER_RESPONSE_NOBACKOFF;
qDebug() << "server returned invalid response." << reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();
return;
}
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