how to download files with ftp url behind http proxy - c++

Question

I am behind a http/https proxy. So to download a file using QNetworkAccessManager, i set the proxy as following:
if(no_proxy)
{
QNetworkProxyFactory::setUseSystemConfiguration (false);
QNetworkProxy::setApplicationProxy(QNetworkProxy::NoProxy);
}
else if(system_proxy)
{
QNetworkProxyQuery pQuery(QUrl(QLatin1String("http://www.google.com")));
QList<QNetworkProxy>listOfProxies =QNetworkProxyFactory::systemProxyForQuery(pQuery);
QNetworkProxy::setApplicationProxy(listOfProxies.first());
}
else if(manual_proxy)
{
proxy.setHostName(address);
proxy.setPort(port);
if(http_proxy)
proxy.setType(QNetworkProxy::HttpProxy);
else if(socks_proxy)
proxy.setType(QNetworkProxy::Socks5Proxy);
else if(ftp_proxy)
proxy.setType(QNetworkProxy::FtpCachingProxy);
QNetworkProxy::setApplicationProxy(proxy);
}
Now behind http squid proxy server, this code works fine in case of http urls. But, if i try to download a file with ftp url the download fails with the error
no suitable proxy found
It does not seem to use http proxy for ftp urls. But, we have such options like in firefox:
use this proxy server for all protocols
How to do similar thing in Qt!
Update:
void DownloadThread::startDownload()
{
QString args =downUrl,tempFN;
QUrl url = QUrl::fromEncoded(args.toLocal8Bit());
request.setUrl(url);
request.setRawHeader("User-Agent", userAgent);
request.setAttribute(QNetworkRequest::HttpPipeliningAllowedAttribute, true);
reply.setCookieJar(cookieJar);
reply=manager.get(request);
connect(reply, SIGNAL(readyRead()),this,
SLOT(saveToDisk()));
...
}

Answer 1

Have you tried explicitly setting the Qftp proxy?
int setProxy ( const QString & host, quint16 port )
That might get you more joy, but yes, you have to set the proxies up for each connection normally, however, there is always the possibility that the proxy you are trying to use doesn't support FTP? If you pass me some more details about the proxy and where your problems lie (request/response code for example)
Also in squid.conf may want to change/add the following in case they are not present
acl SSL_ports port 443 21
acl FTP proto FTP
always_direct allow FTP
http_access allow ftp
Also, worth checking that the firewall allows port 20, 21 & 443 (I know its a simple check, but often I find its things like these that can be a real pain to find as a root cause).
Do you have a copy of the log file that is generated? it would be interesting/helpful to see what error code is being returned. Also, have you tried manually stepping through the program to see what is contained in the variables at run-time, that would give you a better picture of what is happening, as it may be that everything is fine and that there is a simple way to progress which the contents of the variables will lead you to in short order (might not be the case but it usually worth a try).