QT4 HTTP Example and Redirecting

[jiveaxe]

Hi,
I was trying the HTTP Example of qt4 documentation and noticed that it can't manage itself the status code 302, it can't perform a redirection.

An example is this link:
http://next.videogame.it/img/articol...e.cover.T5.jpg

With the line below I get the new url:

QString newLocation = responseHeader.value("Location");

QString newLocation = responseHeader.value("Location");

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But I don't know how to use it.

Have anybody some tips for me?

Thanks

EDITED: HTTP Example

[wysota]

When you receive the new location simply change the url of the request to the one you received in the location header and resubmit the request.

[profoX]

I had the same problem sometime ago.
I solved it like this:

self.connect(self.http, SIGNAL("responseHeaderReceived(const QHttpResponseHeader &)"), self.handleHeaderResponse)
 
[...]
 
    def handleHeaderResponse(self, resp):
        code = resp.statusCode()
        if (code >= 300 and code < 400 and resp.hasKey("location")):
            location = QUrl(resp.value("location"))
            self.http.setHost(location.host())
            self.http.get(location.toString())

self.connect(self.http, SIGNAL("responseHeaderReceived(const QHttpResponseHeader &)"), self.handleHeaderResponse)

[...]

    def handleHeaderResponse(self, resp):
        code = resp.statusCode()
        if (code >= 300 and code < 400 and resp.hasKey("location")):
            location = QUrl(resp.value("location"))
            self.http.setHost(location.host())
            self.http.get(location.toString())

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As you can see it's copied from my PyQt4 application... In C++ it should be something like this (not tested!)

connect(http, SIGNAL(responseHeaderReceived(const QHttpResponseHeader &)), this, SLOT(handleHeaderResponse(const QHttpResponseHeader &)));
 
[...]
 
    void MyClass::handleHeaderResponse(const QHttpResponseHeader &resp):
        int code = resp.statusCode();
        if (code >= 300 and code < 400 and resp.hasKey("location")) {
            QUrl location = QUrl(resp.value("location"));
            http.setHost(location.host());
            http.get(location.toString());
        }

connect(http, SIGNAL(responseHeaderReceived(const QHttpResponseHeader &)), this, SLOT(handleHeaderResponse(const QHttpResponseHeader &)));

[...]

    void MyClass::handleHeaderResponse(const QHttpResponseHeader &resp):
        int code = resp.statusCode();
        if (code >= 300 and code < 400 and resp.hasKey("location")) {
            QUrl location = QUrl(resp.value("location"));
            http.setHost(location.host());
            http.get(location.toString());
        }

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Hope it helps you!

[jiveaxe]

I'm trying different ways but with no luck.

First of all the code:

class InternetJob: public QObject
{
	Q_OBJECT
 
	public:
		InternetJob(const QString &u);
		QByteArray getData(){return data;}
		int getStatusCode(){return statusCode;}
		QString getLocation(){return location;}
		bool isRequestAborted(){return httpRequestAborted;}
		bool isRedirecting(){return needRedirect;}
		void download();
 
	private slots:
		void httpRequestFinished(int requestId, bool error);
		void readResponseHeader(const QHttpResponseHeader &responseHeader);
 
	signals:
		void requestFinished();
 
	private:
		QHttp *http;
		QUrl url;
		bool httpRequestAborted;
		int httpGetId;
		QByteArray data;
		int statusCode;
		QString location;
};
 
InternetJob::InternetJob(const QString &u)
	: url(u)
{
	http = new QHttp;
	connect(http, SIGNAL(responseHeaderReceived(const QHttpResponseHeader &)), this, SLOT(readResponseHeader(const QHttpResponseHeader &)));
	connect(http, SIGNAL(requestFinished(int, bool)), this, SLOT(httpRequestFinished(int, bool)));
 
	download();
}
 
void InternetJob::download()
{
	QString query;
	for(int i = 0; i < url.queryItems().size(); ) {
		query += url.queryItems().at(i).first + "=" + url.queryItems().at(i).second;
		if(++i < url.queryItems().size())
			query += "&";
	}
 
	QHttpRequestHeader header;
	if(url.queryItems().size() > 0)
		header.setRequest("GET", url.path() + "?" + QUrl::toPercentEncoding(query,"&="));
	else
		header.setRequest("GET", url.path());
	header.setValue("Host", url.host());
 
	httpRequestAborted = false;
	http->setHost(url.host());
	httpGetId = http->request(header);
	qDebug() << "job id = " << httpGetId;
}
 
void InternetJob::readResponseHeader(const QHttpResponseHeader &responseHeader)
{
	statusCode = responseHeader.statusCode();
	QRegExp rx("\?$");
 
	switch(statusCode) {
		case 200:
		case 301:
		case 303:
		case 307:
			break;
 
		case 302:
			location = responseHeader.value("Location");
			// Remove trailing "?"
			location.remove(rx.indexIn(location), 1);
			httpRequestAborted = true;
			http->abort();
			break;
 
		default:
			qDebug() << QString(trUtf8("Download failed: %1.").arg(responseHeader.reasonPhrase()));
			httpRequestAborted = true;
			http->abort();
	}
}
 
void InternetJob::httpRequestFinished(int requestId, bool error)
{
	if (requestId != httpGetId)
		return;
	qDebug() << "job finished = " << requestId;
	if (httpRequestAborted) {
		qDebug() << "Request Aborted. Status Code: " << statusCode;
		if(statusCode == 302) {
			url.setUrl(location);
			download();
			return;
		}
		else {
			emit requestFinished();
			return;
		}
	}
 
	if(error)
		qDebug() << QString(trUtf8("Download failed: %1.").arg(http->errorString()));
	else
		data = http->readAll();
	emit requestFinished();
}

class InternetJob: public QObject
{
	Q_OBJECT

	public:
		InternetJob(const QString &u);
		QByteArray getData(){return data;}
		int getStatusCode(){return statusCode;}
		QString getLocation(){return location;}
		bool isRequestAborted(){return httpRequestAborted;}
		bool isRedirecting(){return needRedirect;}
		void download();

	private slots:
		void httpRequestFinished(int requestId, bool error);
		void readResponseHeader(const QHttpResponseHeader &responseHeader);
		
	signals:
		void requestFinished();
		
	private:
		QHttp *http;
		QUrl url;
		bool httpRequestAborted;
		int httpGetId;
		QByteArray data;
		int statusCode;
		QString location;
};

InternetJob::InternetJob(const QString &u)
	: url(u)
{
	http = new QHttp;
	connect(http, SIGNAL(responseHeaderReceived(const QHttpResponseHeader &)), this, SLOT(readResponseHeader(const QHttpResponseHeader &)));
	connect(http, SIGNAL(requestFinished(int, bool)), this, SLOT(httpRequestFinished(int, bool)));

	download();
}

void InternetJob::download()
{
	QString query;
	for(int i = 0; i < url.queryItems().size(); ) {
		query += url.queryItems().at(i).first + "=" + url.queryItems().at(i).second;
		if(++i < url.queryItems().size())
			query += "&";
	}

	QHttpRequestHeader header;
	if(url.queryItems().size() > 0)
		header.setRequest("GET", url.path() + "?" + QUrl::toPercentEncoding(query,"&="));
	else
		header.setRequest("GET", url.path());
	header.setValue("Host", url.host());
	
	httpRequestAborted = false;
	http->setHost(url.host());
	httpGetId = http->request(header);
	qDebug() << "job id = " << httpGetId;
}

void InternetJob::readResponseHeader(const QHttpResponseHeader &responseHeader)
{
	statusCode = responseHeader.statusCode();
	QRegExp rx("\?$");
	
	switch(statusCode) {
		case 200:
		case 301:
		case 303:
		case 307:
			break;

		case 302:
			location = responseHeader.value("Location");
			// Remove trailing "?"
			location.remove(rx.indexIn(location), 1);
			httpRequestAborted = true;
			http->abort();
			break;

		default:
			qDebug() << QString(trUtf8("Download failed: %1.").arg(responseHeader.reasonPhrase()));
			httpRequestAborted = true;
			http->abort();
	}
}

void InternetJob::httpRequestFinished(int requestId, bool error)
{
	if (requestId != httpGetId)
		return;
	qDebug() << "job finished = " << requestId;
	if (httpRequestAborted) {
		qDebug() << "Request Aborted. Status Code: " << statusCode;
		if(statusCode == 302) {
			url.setUrl(location);
			download();
			return;
		}
		else {
			emit requestFinished();
			return;
		}
	}

	if(error)
		qDebug() << QString(trUtf8("Download failed: %1.").arg(http->errorString()));
	else
		data = http->readAll();
	emit requestFinished();
}

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The code above works well until the http status code is 200; if the status code is 302 it starts a new http->request(...) but after it neither responseHeaderReceived nor httpRequestFinished signals are emitted.

Where is my mistake?

Thanks