What happens if a publisher stop using PuSH?

[Poluxus]

Hi.

I got this address : http://v1.theglobeandmail.com/generated/rss/BN/Business.xml
from previous version of the rss feed of globeandmail.
But now, the new address : http://www.theglobeandmail.com/report-on-business/?service=rss
is no longer attach to a hub.

Is there something that alerts us if a publisher stop using PuSH. I see nothing about this in the spec.

And an additional question
When you go on : http://v1.theglobeandmail.com/generated/rss/BN/Business.xml, it redirects to : http://feeds.feedburner.com/TheGlobeAndMail-Business but the rel="self" on this page is bad : error 404.
If i follow the new specification i shoud subscibe to this topic, but it's not working.... I'm a little confused what to do here

[Jay Rossiter]

You must always continue pulling the source feed, at least occasionally, even if you rely on push for regular updates.

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[Roman]

On Wed, Feb 20, 2013 at 1:30 AM, Poluxus <lafeuill...@gmail.com> wrote:

Hi.

I got this address : http://v1.theglobeandmail.com/generated/rss/BN/Business.xml
from previous version of the rss feed of globeandmail.
But now, the new address : http://www.theglobeandmail.com/report-on-business/?service=rss
is no longer attach to a hub.

Is there something that alerts us if a publisher stop using PuSH. I see nothing about this in the spec.

Unfortunately, this feed appears to be broken. And no, the hub won't notify you when that happens.

And an additional question
When you go on : http://v1.theglobeandmail.com/generated/rss/BN/Business.xml, it redirects to : http://feeds.feedburner.com/TheGlobeAndMail-Business but the rel="self" on this page is bad : error 404.
If i follow the new specification i shoud subscibe to this topic, but it's not working.... I'm a little confused what to do here

As far as I can tell, there is no topic you can subscribe to if you want to get updates from http://v1.theglobeandmail.com/generated/rss/BN/Business.xml or its equivalent.

Roman.

[Poluxus]

Thanks.

I know the feed i gave you was broken, it was for the example.

Is there a system to tell if a publisher stops using PuSH?

@Jay : I thought that PuSH was created to avoid polling the source

[Roman]

On Wed, Feb 20, 2013 at 5:04 PM, Poluxus <lafeuill...@gmail.com> wrote:

Thanks.

I know the feed i gave you was broken, it was for the example.

Is there a system to tell if a publisher stops using PuSH?

Not at the moment, no.

@Jay : I thought that PuSH was created to avoid polling the source

It was indeed. Polling is still needed for feeds that don't support PuSH properly. Ideally, the hub should take care of polling for you but we are not there yet.

Roman.

[Poluxus]

Thanks.

Have a good day

[Bob Wyman]

On Wed, Feb 20, 2013 at 11:04 AM, Poluxus <lafeuill...@gmail.com> wrote:

Thanks.

I know the feed i gave you was broken, it was for the example.

Is there a system to tell if a publisher stops using PuSH?

How could anyone other than the publisher know that the publisher had stopped using PubSubHubbub? From a hub's point of view, a feed that is updated infrequently and one that never updates are largely indistinguishable. If you were polling the feed, you might notice a removal of the auto-discovery data in the feed (i.e. <link rel="hub"...),  but that data isn't required by hubs, it is only there as a hint for potential subscribers. Thus, removal of the data doesn't really tell you very much; it could be just that the publisher left it out by accident. The publisher could continue to notify the hub of new updates even for a feed without discovery data... A system that tried to deduce when a publisher has stopped using PubSubHubbub would be trying to "prove a negative." That is often impossible.

 

@Jay : I thought that PuSH was created to avoid polling the source

Certainly, a major motivation for PubSubHubbub is the dramatic reduction in feed polling that results from its use. However, in order to improve the ease of adoption, it is also intended to a be a fairly simple system and thus doesn't specifically address all possible user requirements. As suggested above, being able to notify subscribers when publishers stop using PubSubHubbub would require additional complexity in the protocol and would also probably rely on a hard to enforce requirement that publishers must notify hubs in some manner when they cease to use the hub. 

Subscribers who wish to discover when publishers stop using PubSubHubbub and who are willing to rely on the removal of auto-discovery data in feeds as an indication of continued hub use, can easily achieve a "compromise" position by polling feeds to verify the auto-discovery data whenever they refresh their subscriptions. While such a pattern would still require some polling, it is likely that it would result in orders of magnitude less polling than would be done without PubSubHubbub.

[Jay Rossiter]

I disagree with this statement entirely.  It's not a replacement for polling, it's an addition to.  It's something to create a *reduction* in polling.  There are far too many unaccounted cases that will break PuSH, or where the hub can simply fail, resulting in unpublished data.  Even in an "almost perfect" scenario, polling is still required periodically.  Not to do so would be irresponsible as a data consumer.