ao2.it
Antonio Ospite, attacchi teoristici

I use RSS/Atom feeds a lot, they are a relatively efficient way to follow stuff around the web, and they are also privacy-friendly tools to a certain degree: I can follow my friends and family on Youtube, Flickr, and even Twitter (at least as long as API 1.0 is up and running, bah...), without having to explicitly tell the companies behind those sites whom I am friend with. Privacy is not only about “what you do”, but also about “whom you know”.

Lately I wanted to access the syndication feed of a site to which authentication is necessary. In particular, the site is a private Wiki using MediaWiki and I wanted to track the [[Special:RecentChanges]] page, using the feed reader, in order to know when other users updated the content.

The URL of the RecentChanges feed is something like this:
http://private.example.com/mediawiki/index.php?title=Special:RecentChanges&feed=atom

The feed reader I use is Liferea.

By just adding the URL to Liferea an error is produced:

The URL you want Liferea to subscribe to points to a webpage and the auto discovery found no feeds on this page. Maybe this webpage just does not support feed auto discovery.Source points to HTML document

What happens is that Liferea gets redirected to the “Login required” page. How to avoid this?

The right answer is: cookies! Isn't it always?

Liferea supports cookies when they are in the Netscape format; however this mechanism is not well integrated with its embedded web browser: even if you open the site in a tab in Liferea and authenticate from there, the cookies are not available for the feed reader to use; so some extra steps are needed.

This is one possible way to retrieve the necessary cookies and use them in Liferea:

1. Install the Export Cookies extension for Firefox (Firebug can export cookies too BTW).
2. Log in to the private Wiki checking the option Remember me on this computer.
3. Export the cookies to $HOME/cookies.txt, the file contains something like:

   private.example.com	FALSE	/	FALSE	1361622084	wikidb_mw_UserID	7
   private.example.com	FALSE	/	FALSE	1361622087	wikidb_mw_UserName	Ao2
   private.example.com	FALSE	/	FALSE	1361622091	wikidb_mw_Token	74755fb44dccd6d3a6154b5c6abfb536
   

4. Paste the lines from above in $HOME/liferea_1.8/cookies.txt
5. Add/check again the feed in Liferea with the source URL from above:
   http://private.example.com/mediawiki/index.php?title=Special:RecentChanges&feed=atom

Now Liferea can access the feed of the private Wiki.