QNetworkAccessManager and DNS resolution

Question

I'm using qnetworkaccessmanager for making HTTP requests. The hostname (FQDN) of the server I connect to, has two IP addresses in DNS and I need to control which one to use. The obvious solution (change the URL's hostname to IP address) does not work, because the server sends back a 302 redirect with the original hostname in the location field. If I follow the redirect, QT seems to randomly choose which IP it connects to.

Is there a way to tell qnetworkaccessmanager to use a given IP address on the TCP connect() level and use the Host header from the URL ? If not, any workaround suggestions are appreciated.

Edit: using QT 4.7.4

Answer 1

This seems to work and is a simple workaround: set the QNetworkRequest's URL to contain the desired IP address to connect to in the host part, but also use setCustomHeader("Host", "<server hostname>") to avoid the redirection. In my tests, QT will always use the IP set in the URL.

Answer 2

You should be able to build a custom QNetworkRequest and specify the QNetworkRequest::LocationHeader to force a specific destination URL in case of a redirect. If you look at QNetworkAccessManager::sendCustomRequest (QNetworkAccessManager::sendCustomRequest doc), and QNetworkRequest::Attribute::RedirectionTarget and QNetworkRequest::KnownHeaders it should give you some hints about it.

(footnote: I'm using the harmattan documentation as the proper Qt documentation is down as of time of answer)