reva: properties support

[butonic]

-> running `props':
 0. init.................. pass
 1. begin................. pass
 2. propfind_invalid...... pass
 3. propfind_invalid2..... pass
 4. propfind_d0........... pass
 5. propinit.............. pass
 6. propset............... FAIL (PROPPATCH on `/remote.php/webdav/litmus/prop': 501 Not Implemented)
 7. propget............... SKIPPED
 8. propextended.......... pass
 9. propmove.............. SKIPPED
10. propget............... SKIPPED
11. propdeletes........... SKIPPED
12. propget............... SKIPPED
13. propreplace........... SKIPPED
14. propget............... SKIPPED
15. propnullns............ SKIPPED
16. propget............... SKIPPED
17. propremoveset......... SKIPPED
18. propget............... SKIPPED
19. propsetremove......... SKIPPED
20. propget............... SKIPPED
21. propvalnspace......... SKIPPED
22. propwformed........... pass
23. propinit.............. pass
24. propmanyns............ FAIL (PROPPATCH on `/remote.php/webdav/litmus/prop': 501 Not Implemented)
25. propget............... FAIL (No value given for property {http://example.com/kappa}somename)
26. propcleanup........... pass
27. finish................ pass
-> 14 tests were skipped.
<- summary for `props': of 14 tests run: 11 passed, 3 failed. 78.6%

needs cs3 api changes, unless we want to store properties in a different service

[tomneedham]

Hmm depends on the use cases - what do we expect to use this for? We should think about this carefully first as it might become clear where to store the data. There is also a bad tendancy to use this as a key value dump.... It ends up needing to be quite performant.

[tomneedham]

Is this a space for the storage to define metadata? Or (more our use case) is it for ownCloud to store key value data against file ids? What webdav clients do we know that really make use of this? I've seen quite some entries from the windows network drive mount client - but only for caching values.

[butonic]

several webdav clients want to store metadata und they use properties to do that. but I agree we should try to get a list of clients that really need that. @DeepDiver1975 might have an idea where to get that.

Hm, if we know which keys are stored for caching we could redirect those to a real cache.

[DeepDiver1975]

To my understanding properties are a central mechanism in WebDAV - they are not optional.

Please note that S3 as well has this type of key-value-based meta data.

We need to have this as integral part of our architecture.

[butonic]

It makes sense to separate APIs for things like tags from basic file management. It allows you to implement a storage with optional capabilities. cs3 already did that for tagging: https://github.com/cernbox/cs3apis/blob/master/cs3/tag/v0alpha/tag.proto

however, tags have a different meaning than extended attributes (and comments for that matter). An I don't think misusing the tag api for extended attributes / properties or even comments is the right thing to do.

[butonic]

• CS3 now supports it add gateway service and arbitrary metadata support cs3org/cs3apis#31
• update proppatch & propfind code in ocdavsvc

[refs]

move to reva?