I like the utility of the canonical property.
The app tag is not particularly scaleable, and adds several brittle complexity obligations to all clients.
- The blockchain doesn't know jack about apps.
- The universal url schema is either fixed for all time, or everyone in the steemverse needs to change their schemas
I'd suggest we start with both a canonical and an app_account (that is an account associated with only the app that assisted in creating the post).
At some point in the future we can either:
- agree on a kind of "meta schema" that will allow the account
app_accountto publish a configuration set for in a special tx; so that all clients can generate the correct urls by pulling the most recent tx for that app_account. - the app_account could publish special tx with a javscript function in the body that would take a post and transform it into the correct canonical url. (this is a terrible idea for all the obvious reasons)
- have a standard js lib in an npm style repo somewhere that everyone has access to, with the functions describe in #2, but vetted by the publisher (this is terrible for a mostly different set of reasons)
If we get sufficient community support, and add in the concept of trusted app_accounts (with some additional complexity) any of the above would get the job done 'well enough'.
Oh, I agree this really does need to happen. For all our sakes.