[Project_owners] XMLHttpRequest - how can one bypass cache?

Andrey Gromyko andrey at gromyko.name
Thu Aug 3 23:40:55 EDT 2006


On Thu, 03 Aug 2006 21:17:24 +0100
Matthew Wilson <matthew at mjwilson.demon.co.uk> wrote:

> Andrey Gromyko wrote:
> > Hi All,
> > 
> > In the NewsFox extension I use next lines to download feed(s):
> > 
> >     var xmlhttp = new XMLHttpRequest();
> >     xmlhttp.open("get", feed.url);
> >     xmlhttp.setRequestHeader("User-Agent", "Mozilla/5.0
> > NewsFox/0.3.4"); xmlhttp.overrideMimeType("application/xml");
> >     xmlhttp.onload = function() { checkFeed(index,
> > xmlhttp.responseXML); } xmlhttp.send(null);
> > 
> > Adding the next line before send doesn't help to avoid the use of
> > Firefox's cache: xmlhttp.channel.loadFlags =
> > Components.interfaces.nsICachingChannel.LOAD_BYPASS_CACHE;
> > 
> > And that causes problems with some feeds. Does anybody know how can
> > I bypass the cache? Similarly tp the behaviour of the browser when
> > somebody pressed Shift+Reload.
> 
> Arguably you should be respecting the cache here. If a feed is set up
> so that newsreaders only refetch it every hour (for example), then
> that's a deliberate strategy to reduce bandwidth, and a well-behaved
> client follow the rules.

There is at least one news-feed I know which has 100+ new entries a day and Firefox (which, I assume, "respects the cache") doesn't fetch an updated xml without unless I press Shift+Reload. What would you say about that? (rhetorical question...)

Regards,
Andrey


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