WIP: Common constraints - identifiers

[mlagally]

---

Preview | Diff

[mlagally]

I revised the draft taking the feedback from @benfrancis into account. @benfrancis all, please review again.

[benfrancis]

• A UUID is not a valid URI
• The HTML in this PR doesn't render correctly
• The proposed text is very verbose and a lot of it is redundant
• I think best practice recommendations like this really belong in the Thing Description specification since they apply to all Thing Descriptions, not just those which conform with a profile

I don't have a problem with recommending URNs (containing UUIDs) as IDs, as long as any URI is allowed.

If you really feel that it's important for this recommendation to be made in the Profile specification, I suggest reducing this section down to a single assertion which says something along the lines of:

"It is RECOMMENDED that a Web Thing's Thing Description uses a URN [[URN]] containing a UUID [[rfc4122]] as the value of its id member, so that the Thing has a globally unique identifier."

[egekorkan]

I agree with @benfrancis but the most important thing here is to remove the last assertion since the TD spec says:

Ideally, any required immutable identifiers SHOULD only be made available via affordances, such as a property, whose value can only be obtained after appropriate authentication and authorization, and managed separately from the TD identifier.