Talk:LLSD
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LLSD JSON-ish notation
The login sequence appears to use "binary" LLSD for two of the variables, home and look_at. Unfortunately the format doesn't match up exactly with what is documented on this wiki. Sample values:
{'region_handle':[r255232, r256512], 'position':[r33.6, r33.71, r43.13], 'look_at':[r34.6, r33.71, r43.13]}
[r0.99967899999999998428,r-0.025334599999999998787,r0]
No size values, and the map keys are encased in single quotes. Is this normal? -- —The preceding unsigned comment was added by Eddy Stryker
- Oh wow, notation format. Ummmmm, I never documented that, did I. LLSD started it's life as a json-like language, with a well defined serialization which is not actually documented. I'll get on that. Phoenix Linden 16:10, 6 April 2007 (PDT)
- Documentation has been added. Phoenix Linden 17:34, 12 April 2007 (PDT)
Versioning?
Personally I miss a few things here, especially the versioning/compatibility. Sure you can asume that older request just have less keys in a map, and that might work well for things like statistics results. But as soon as you want to call a method, it is much better to make the version obvious. You can encode that in a key/value pair, but it is much better to have that in a fixed element for routing (you can route requests for inventories to different servers, depending on the interface version)
I see a Version:i1 in the notation example for the teleport, which makes it clear, that this element is used already in LL. Maybe it is hard for you to make it to a llsd envelop, but I think you guys will have great use for it.
<llsd> <method version="1" interface="simstatistics" message="result" /> ...
or something like that.--Bernd Elswit 10:27, 18 May 2007 (PDT)
Efficient binary support
maybe a more efficient binary transport can be added, too? For example Adobe's ASCII85 allows better compression (however you need to escape less-than and ampersand and CDATA). Very efficient could be precalculated huffman tables for the most common file formats.
Sample code at the end of the page: http://www.javaworld.com/javaworld/javatips/jw-javatip117.html
--Bernd Elswit 10:26, 18 May 2007 (PDT)
- Any time that we need to conserve space or cpu resources, we will use zlib routines or binary serialization. Phoenix Linden 12:41, 21 May 2007 (PDT)
hexadecimal ?
does the integer type allow hexadecimal values ? e.g. 0xffcc00 instead of entering 16763904 ?
SignpostMarv Martin 09:54, 31 May 2007 (PDT)
Binary map and array encoding ?
The description is not clear how the delimiters for map and array elements should be encoded. See here:
array '[' + htonl(array.length()) + ''(''child0'','' child1'','' ...'')'' + ']'
map '{' + htonl(map.length()) + ''((''key0'',''value0''),(''key1, value1''),'' ...'')'' + '}'
Especially the binary encoding of the
''
marked values is not defined. As I am sitting at an implementation of this, I will try with the supposed reference implementation llsd.py and see what that actually does for this part.
--Leffard Lassard 10:04, 27 March 2008 (PDT)
From my own research it is more like this:
array '[' + htonl(array.length()) + child0 + child1 + ']'
map '{' + htonl(map.length()) + 'k' + htonl(key0.length) + key0 + value0 + 'k' + htonl(key1.length) + key1 + value 1 ... + '}'
--Leffard Lassard 11:26, 28 March 2008 (PDT)
Map-keys in the reference implementation at reference implementation seem to not support full UTF8 Strings. They seem to support only ASCII characters, which seems to be a python dictionary type problem.
--Leffard Lassard 06:26, 3 April 2008 (PDT)