[Opensim-dev] dispatcher interface

[Mic Bowman]

On Tue, Dec 23, 2014 at 5:03 PM, Dahlia Trimble <dahliatrimble at gmail.com>
wrote:

>
>> Show me a mechanism in opensim that is well layered enough to handle
>> these messages with both binary & text encoding over both streaming &
>> packet protocols and i will gladly use it.
>>
>
> I used the libomv OSD and it's various serializations. They worked very
> well. I've found the JSON to be quite usable with python, javascript ,and a
> few c++ libs I've tried.  I've not had as good of luck with the various
> binary LLSD ports out there though and I wrote my own for c++. I've used
> the various serializations both in TCP and UDP with good success.
>

I don't think the JSON encoding is the problem. There is JSON all over.
JSON RPC. JSON for submitting simulator to simulator messages. Most are
using the OSD serializer for it. I personally use Newtonsoft because 1) its
significantly faster and 2) it can re-ify into object classes easily
(meaning that the json can be converted transparently into an C# object of
a specific per-message-type class without great big switch statements). The
reification is convenient for me because it means that the message handlers
dont care how the messages came in (abstraction for layering, means I can
replace the JSON encoding with anything that builds the classes in a
consistent way) & they don't have to dig through multiple levels of
dictionaries to find a particular value (enforcement of the structure). If
I want to add a new method of security, I only have one place i need to
change.

That being said... the problem is that there is no consistency in the use
of json. Some times we encode the method in the body of the json, sometimes
in the url. Sometimes the decoding happens in a module (see
NeighbourHandlers). Sometimes it happens in the HTTP server handlers (JSON
RPC). Lets just say that we wanted to actually add a method for authorizing
messages to ensure that they come from an adjacent simulator... where would
you make the change?

Oh... and that doesn't even begin to touch the fact that we have some
modules using xmlrpc (HG) and some using json.

Justin is right that adding one more is probably not a good idea.

--mic
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