ISSUE-32: How can clients discover that a resource is an LDPR or LDPC, and what features are supported?

discovery

How can clients discover that a resource is an LDPR or LDPC, and what features are supported?

State:
CLOSED
Product:
Linked Data Platform Spec
Raised by:
Richard Cyganiak
Opened on:
2012-11-05
Description:
Currently, the spec doesn't have a reliable mechanism that would allow a client to discover whether a resource is an LDPR, and what features exactly are supported by an LDPC. For example, a client has to guess whether xxx?firstPage will return anything, or whether xxx?non-member-properties does something useful. This means that clients will have to make lots of speculative HTTP requests trying to find out whether certain features are supported. Same for trying to update an LDPR via PUT — the client has no way of knowing whether it even is an LDPR.

I think this is wasteful, will make clients brittle, and doesn't exactly honour the URI opacity axiom.

Servers should be able to announce their capabilities to clients, so that clients can discover them without blindly poking around. This could be done in various ways—via OPTIONS, via HTTP headers, via links in the RDF representations, and perhaps other ways.

This is related to ISSUE-7 and the notion of discoverable “container/resource affordances”.
Related Actions Items:
No related actions
Related emails:
  1. LDP Rec (from eric@w3.org on 2015-02-20)
  2. Action 51, the final stake in the heart of issue-32 (from johnarwe@us.ibm.com on 2013-07-15)
  3. ISSUE-32 and OPTIONS (was: More issues available for review in editor's draft: accept-post and options (from sspeiche@gmail.com on 2013-07-08)
  4. Re: More issues available for review in editor's draft: accept-post and options (from sspeiche@gmail.com on 2013-07-08)
  5. More issues available for review in editor's draft: accept-post and options (from johnarwe@us.ibm.com on 2013-07-08)
  6. Re: Discovery/Affordances (Issue-32/Issue-57) (from Erik.Wilde@emc.com on 2013-06-14)
  7. Re: Discovery/Affordances (Issue-32/Issue-57) (from tthibodeau@openlinksw.com on 2013-06-14)
  8. Re: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-14)
  9. Re: Discovery/Affordances (Issue-32/Issue-57) (from kidehen@openlinksw.com on 2013-06-13)
  10. Re: Discovery/Affordances (Issue-32/Issue-57) (from Erik.Wilde@emc.com on 2013-06-13)
  11. Re: Discovery/Affordances (Issue-32/Issue-57) (from pierre-antoine.champin@liris.cnrs.fr on 2013-06-13)
  12. Re: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-13)
  13. Re: Discovery/Affordances (Issue-32/Issue-57) (from bertails@w3.org on 2013-06-13)
  14. Re: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-13)
  15. Re: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-13)
  16. Re: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-13)
  17. Re: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-12)
  18. Re: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-12)
  19. Re: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-11)
  20. Re: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-11)
  21. re: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-11)
  22. Re: Discovery/Affordances (Issue-32/Issue-57) (from kidehen@openlinksw.com on 2013-06-11)
  23. re: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-11)
  24. Re: proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-11)
  25. Re: proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from Erik.Wilde@emc.com on 2013-06-11)
  26. Re: proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from kidehen@openlinksw.com on 2013-06-11)
  27. Re: proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-11)
  28. Re: proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-11)
  29. Re: proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-11)
  30. Re: proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-11)
  31. proposal on ldp:profile ( Issue-48 ) -- was: Discovery/Affordances (Issue-32/Issue-57) (from henry.story@bblfish.net on 2013-06-11)
  32. Re: Discovery/Affordances (Issue-32/Issue-57) (from Erik.Wilde@emc.com on 2013-06-10)
  33. Re: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-10)
  34. Re: Discovery/Affordances (Issue-32/Issue-57) (from kidehen@openlinksw.com on 2013-06-10)
  35. Re: Discovery/Affordances (Issue-32/Issue-57) (from kidehen@openlinksw.com on 2013-06-10)
  36. Re: Discovery/Affordances (Issue-32/Issue-57) (from Erik.Wilde@emc.com on 2013-06-10)
  37. Re: Discovery/Affordances (Issue-32/Issue-57) (from lehors@us.ibm.com on 2013-06-10)
  38. Re: Discovery/Affordances (from henry.story@bblfish.net on 2013-06-10)
  39. Re: Discovery/Affordances (from lehors@us.ibm.com on 2013-06-10)
  40. ldp-ISSUE-80 (post create media type): How does a client know which POST requests create new resources [Linked Data Platform Spec] (from sysbot+tracker@w3.org on 2013-06-07)
  41. Re: ldp-ISSUE-74 (conditional requests required): How does a client know if conditional requests are required [Linked Data Platform core] (from henry.story@bblfish.net on 2013-05-23)
  42. ldp-ISSUE-74 (conditional requests required): How does a client know if conditional requests are required [Linked Data Platform core] (from sysbot+tracker@w3.org on 2013-05-23)
  43. ldp-ISSUE-32 (affordances): new issues coming (from johnarwe@us.ibm.com on 2013-05-23)
  44. Re: HEAD vs OPTIONS (from sspeiche@gmail.com on 2013-05-17)
  45. Re: Issue-32 affordances (from johnarwe@us.ibm.com on 2013-05-17)
  46. Re: Define a minimal restriction on LDPR representations (from rgarcia@fi.upm.es on 2013-05-17)
  47. Re: Define a minimal restriction on LDPR representations (from ashok.malhotra@oracle.com on 2013-05-16)
  48. Re: Issue-32 affordances (from nmihindu@fi.upm.es on 2013-05-14)
  49. Re: LDP minutes for May 6 (from lehors@us.ibm.com on 2013-05-09)
  50. Re: LDP minutes for May 6 (from johnarwe@us.ibm.com on 2013-05-08)
  51. Issue-32 affordances (from johnarwe@us.ibm.com on 2013-04-30)
  52. Re: ldp-ISSUE-59 (recursive-delete): Reconsider usage of Aggregate/Composite construct to get predictable container delete behavior [Linked Data Platform core] (from ashok.malhotra@oracle.com on 2013-04-05)
  53. Re: ldp-ISSUE-57 (LDP Service ID): How can a client determine that it is in communication with an LDP service? [Linked Data Platform core] (from henry.story@bblfish.net on 2013-03-16)
  54. ldp-ISSUE-57 (LDP Service ID): How can a client determine that it is in communication with an LDP service? [Linked Data Platform core] (from sysbot+tracker@w3.org on 2013-03-15)
  55. Re: Review and Comments for Linked Data Platform FPWD (from david@3roundstones.com on 2013-03-05)
  56. Re: Review and Comments for Linked Data Platform FPWD (from sspeiche@gmail.com on 2013-03-04)
  57. Re: Affordances wiki page (from Erik.Wilde@emc.com on 2013-02-25)
  58. Re: Affordances wiki page (from ashok.malhotra@oracle.com on 2013-02-22)
  59. Affordances wiki page (from johnarwe@us.ibm.com on 2013-02-22)
  60. Re: I added some comments to the wiki page for ISSUE-37 (from ashok.malhotra@oracle.com on 2012-12-12)
  61. Re: I added some comments to the wiki page for ISSUE-37 (from andy.seaborne@epimorphics.com on 2012-12-12)
  62. ldp-ISSUE-32 (discovery): How can clients discover that a resource is an LDPR or LDPC, and what features are supported? [Linked Data Platform core] (from sysbot+tracker@w3.org on 2012-11-05)

Related notes:

on the web, this would be most appropriately be done with media types.

Erik Wilde, 12 Nov 2012, 15:28:41

NB: NB: The answer to this issue may or may not provide an answer to ISSUE-57. If so, ISSUE-57 may be closed concurrently.

David Wood, 15 Mar 2013, 18:33:50

Issues 64 and 74 cover portions of this (?firstPage and ?non-member-properties).

John Arwe, 23 May 2013, 21:48:21

Resolved: addressed by closing related issues (80, etc.)
See https://www.w3.org/2013/meeting/ldp/2013-06-19#resolution_4

Arnaud Le Hors, 19 Jun 2013, 18:13:28

The only editorial work that I see is to review the spec again after all the other issues are drafted and see if there are new gaps that subsequent resolutions have introduced. I thought what we said at the F2F is that any such gaps would be new issues, so that nets out to closing this with no spec changes I believe. All the spec changes were agreed to the in the context of other smaller issues.

John Arwe, 8 Jul 2013, 12:36:07

Discussed on July 8 call, meeting record link was wrong.
https://www.w3.org/2013/meeting/ldp/2013-06-18#resolution_2 is the correct one.

John Arwe, 8 Jul 2013, 14:13:03

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