Issue overview: From URI to open array

[jstriebel]

This is a meta issue to track progress and ideas around opening stores. I think it would be a great goal to be able to:

1. Have a clear URI to a zarr hierarchy, group or array
   v3: Define standard "URL" syntax for referencing a specific array, group, attribute within a zarr repository #132
2. Find data under this URI if you open it in a non-zarr-aware client
   v3 core spec: Consider to drop /meta prefix, have file at URI #177
3. Can extract the root location and read the entrypoint metadata field from the URI (e.g. by using a .zarr/.zr3 suffix? see recommended file extension for zarr-v3 stores (.zr3?) #137)
   Consider to remove entrypoint metadata, do not specify root #192
4. Can open groups and arrays specified via URIs after 3:
   • Do we need store configuration in the entrypoint metadata or sth. similar?
     Store type of store in top level metadata ?  #65
   • Node names might need more clarification:
     • Node name character set #56
     • Node name case sensitivity #57
     • The Amazon S3 limit on the length of keys #77
     • Name conventions for zarr #114

Also see

• Native metadata storage #90
• Referencing zarr stores, groups, arrays, and attributes  ome/ngff#144
• Node name & path updates from ZEP 1 review #175

[rabernat]

I plan to spend some time on this next week.

[jstriebel]

@rabernat Please also see @jbms's comment here: #177 (comment)

Do you both have time to join the ZEP meeting this Thursday to discuss this further in person? IMO this issue is the largest blocker for v3 atm and some in person discussions might help.

[rabernat]

Yes I will attend.

[jbms]

I'm also planning to attend.

[jstriebel]

With #211 we have a minimal spec for opening URIs, at least for file stores. This is fine enough for now, further details like URIs for store + zarr-hierarchy path should be discussed in #132.