[Opensim-dev] Questions about hypergrid

[Mike Higgins]

To summarize: before HG:

 1.

    The home server has a copy of your inventory

 2.

    When you log on, the server downloads the inventory list (names &
    UUIDs) into yor viewer

 3.

    When you rez an object, your viewer sends the name  & UUID of the
    object to the server to put in the scene inventory of a region

 4. When someone looks at the object, the server uses the UUID to fetch
    the object and all its parts from the asset server


Then you HG to a foreign grid and rez an object on the ground.

 1. Your viewer sends the name and UUID of the object to the server to
    put in the scene inventory of a region
 2. The foreign server knows that you are a visitor and requests the
    object and all its parts from your home server
 3. The object and all its parts are stored in a combination of cache
    and asset server, using their original UUIDs
 4. When someone looks at the object, its parts are now available
    locally to send to viewers

My questions this time are: Is my understanding correct? Is this the 
correct order? And the big question:

The viewer has your inventory list (name/UUID pairs) and makes requests 
one at a time to rez these objects on the foreign grid. As far as I can 
see, the foreign grid does not have a copy of this list, so it cannot 
iterate through your inventory (be it full or My Suitcase) to request 
all your content. The only items the foreign server can see are the ones 
you drag out of inventory one at a time. Isn't this inherently secure? 
Without a copy of your inventory list, there is no way to guess what 
UUIDs to request from your home server and no way to iterate over all 
possible UUIDs. Or is there some way that the foreign grid can request a 
copy of your inventory list? If not, then I don't see the My Suitcase 
folder making this inherently secure process any better. Why does the My 
Suitcase folder exist?


On 2/17/2017 2:27 PM, Mike Higgins wrote:
>
> I am writing an article on hypergrid transfers, an attempt to improve 
> my own understanding, help others understand and perhaps improve the 
> hypergrid documentation. The things I want to explain in the article 
> is the timing: When are permission tests done? And when is content 
> data actually copied from grid to grid? I think understanding this 
> will make people more comfortable about moving content around the 
> metaverse.
>
> I have a bunch of questions. The documentation at 
> http://opensimulator.org/wiki/Hypergrid does not answer them all. I am 
> trying to track down Diva to see if she will let me pick her brains. I 
> have tried posting questions on IRC. (This comic does a good job of 
> summarizing my opinion of IRC: https://xkcd.com/1782/ ).
>
> So next I'll try asking my questions here. I'll start by asking: Is my 
> understanding (below) of the roles of the server and the viewer 
> correct? (Even before hypergrid is involved.)
>
> When you log into your home grid, the server sends a copy of your 
> inventory list to your viewer. This consists of (mainly) a list of 
> names and UUIDs. The UUIDs are links to objects in the asset server, 
> which in turn are structures made up of many items linked by UUIDs. At 
> the ends of all these links are texture maps, mesh objects, sounds, 
> animations, etc.
>
> When you rez an object in-world, the inventory entry (just the name 
> and UUID) is copied from your avatar inventory to the scene inventory 
> of the region you are in. If you don't have COPY permission to the 
> object, the inventory entry is removed from your avatar inventory. The 
> actual data describing the object isn't involved in this transfer. It 
> stayed where it was in the asset server, was not moved, was not 
> deleted. The data there wasn't even read until someone looked at the 
> newly rezzed object and viewers started making requests so they could 
> render images of it.
>
> Is this understanding basically correct? If my understanding of this 
> is correct, I can move on to hypergrid questions.
>
>
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