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Subscription auto-refresh should auto-nack on unreachable callbacks #64

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
SUMMARY:

If a callback URL is unreachable repeatedly during auto-renewal, the Hub
should consider the subscription as dead.

RELEVANT SECTION:  6.3

COMMENT/REQUEST:

This allows the hub to automatically clean-up and unsubscribe callbacks for
receivers that have disappeared. This also prevents DoS attacks because the
unsubscribe checking time is unpredictable.

Original issue reported on code.google.com by bslatkin on 8 Sep 2009 at 6:07

GoogleCodeExporter commented 9 years ago 
I have a question related to this issue:
If the hub, trying to confirm an "unsubscribe" request, receives a "404 - Not 
Found"
from the subscriber, it currently (code downloaded a couple of days ago) 
schedules a
retry. 
The spec is not entirely clear about this: 
Section 6.2.1. Verification Details
"If the subscriber does not agree with the action, the subscriber MUST respond 
with a
404 "Not Found" response. The hub MUST consider ___other___ server response 
codes
(3xx, 4xx, and 5xx) to mean that the subscription action was not verified. The 
hub
SHOULD retry verification ..."

Does the hub need to abandon the subscription immediately when a "404" is 
received as
the return code for the unsubscribe verification call? With other words is it 
just a
bug in the implementation?
The reference implementation retries 5 times and then abandons the unsubscribe
request. But it is not clear whether the internal state was updated and the
subscription is actually removed. The spec says abandoned requests should not 
change
the internal state.

Original comment by jbeck...@gmail.com on 9 Sep 2009 at 6:32

GoogleCodeExporter commented 9 years ago 
The Hub code was broken. There was a bug. I finally fixed this in r256. Thanks 
for
the keen eyes!

Original comment by bslatkin on 21 Sep 2009 at 7:11

GoogleCodeExporter commented 9 years ago

Original comment by bslatkin on 8 Feb 2010 at 10:43

GoogleCodeExporter commented 9 years ago 
Addressed in 0.3 draft spec

Original comment by bslatkin on 9 Feb 2010 at 6:05