storage: extended attributes / properties

[butonic]

Currently, there is no support for additional file / folder metadata like extended attributes. Webdav has properties, which I would like to map onto extended attributes. The cs3 apis should allow doing that.

[moscicki]

This is still in the making but we are working on it here: https://github.com/cernbox/cs3apis/blob/review/cs3/storageprovider/v0alpha/resources.proto

[butonic]

can we use it for favorites? properties are tied to resources. favorites are depending on the user.

[butonic]

it could be a folder of references

[butonic]

oc uses webdav properties for favorites, however they do not map wall to arbitrary metadata because favorite flags as well as tags are user individual. I will raise tagging (including favorites) as a separate issue, because, AFAICT it makes more sense to implement them in a dedicated service. tracked in #43

[butonic]

fixed with #31

• allows setting arbitrary metadata
• also introduces CanonicalMetadata add gateway service and arbitrary metadata support #31 (comment)