[ghns] ghns status, api, etc.

Jeremy Whiting jeremy at scitools.com
Wed Jul 1 16:08:41 PDT 2009

On Sunday 28 June 2009 22:06:38 Jeremy Whiting wrote:
> Josef, Frank,
> In a plasma meeting I attended yesterday, some interesting things came up.
> They would like to be able to ask knewstuff2 occasionally if certain data
> is updatable. e.g. KNewStuff2::IsEntryUpdateable(Entry*) or something like
> that, and invoke the update either automatically or through some ui of
> their own I guess.  I think we need to nail down the id algorithm/hash
> whatever before that will be feasible. (And before the installed items tab
> in the existing ui will be feasible). So here is how I see each approach.
> Global id (independent of server, etc., as per hotstuff's implementation:
> pros:
> - different hosts can serve the same data
> - registry is simpler on the client
> cons:
> - the algorithm is more complicated
> - the client needs to know which provider to check for updates, the same
> data can come from many different hosts
> server namespaced id
> pros:
> - each host can provide its own algorithm, as long as it uses the same id
> consistently for the same entry, all is well
> - only one host per downloaded item, so only one host to check for updates
> - simpler algorithm
> cons:
> - different hosts serving the same data will not appear to be the same

I've been thinking about this a lot the past couple days, and have tried to 
get a few others to weigh in, but I think I've reached a decision that will be 
good and easy to implement.  I'm thinking of namespacing the id's given to the 
client.  The cons seem to be less for that method, and this also requires very 
little change to either implementation.  I also think that will be the most 
flexible method for other providers and convincing providers to get ghns 
feeds/providers set up.  I'll check to see if I'm getting what I need from the 
ODS and DXS providers (a unique id for each entry)  Josef, I may ask you to 
help me re-add that correctly to HotStuff if it's not in there.  Frank, the id 
tags you provide uniquely identify each entry on the whole site? or just in 
the category the entry is in?


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