Store String Used to Create N5 Reader/Writer

[cmhulbert]

Currently, there is no consistent way across N5Reader/Writers to query what source was used to open the container. It would be convenient if the N5 API stored the URL used to create the instance, and exposed via an API call, e.g. getUrl().

[bogovicj]

This is in progress here: https://github.com/saalfeldlab/n5/tree/wip/KeyValueInterface wherein we added a getBasePath to the N5Reader api https://github.com/saalfeldlab/n5/commit/607233c38b8b263042908d9a0fd8679c495e830f

While working on the AWS backend, @tpietzsch added:

• getContainerURI method to N5Reader https://github.com/saalfeldlab/n5/commit/8f2bfbd2c1dc56bc31afb69c6c00a5df6a3b26fa
• abssoluteURI to KeyValueAccess here

@cmhulbert and I like these. It inspired these ideas:

• Consider removing getBasePath, since getContainerURI
• Consider renaming KeyValueAccess.absoluteURI to uri (since it must always be absolute - we can document that)
• Consider renaming N5Reader.getContainerURI to getUri

[cmhulbert]

I'd also consider having the URI methods actually return the URI object, instead of the string

[tpietzsch]

These ideas sound all good to me.

[bogovicj]

in progress: https://github.com/saalfeldlab/n5/tree/wip/basePath2Uri

[bogovicj]

This commit adds a test for the behavior of N5Reader.getURI and (indirectly) KeyValueAccess.uri . and ensures that FileSystemKeyValueAccess behaves as desired. Do we agree about the expected behavior though?

• MUST begin with a scheme (file:, s3:, etc)
• MUST be absolute
• MUST be normalized (i.e. not contain (/./, /../)

[bogovicj]

N5Readers now provide a getURI that serves this purpose.