Add II login to Candid UI for authenticated calls

[Web3NL]

Requires a canister to implement http_request method and serve /.well-known/ii-alternative-origins with https://a4gq6-oaaaa-aaaab-qaa4q-cai.raw.icp0.io as an origin, as I currently understand.

If this is a good idea and there is support for this feature, I'm willing to start working on a PR.

[chenyan-dfinity]

Sounds like a good feature. Looking forward to your PR :)

[Web3NL]

See this demo and forked repo

For testing I have a canister with:

http_request query method with update = ?true (see upgrade to update)

http_request_update and serves /.well-known/ii-alternative-origins with my self deployed candid ui canister as an alternative origin

hello query method that only answers if caller = allowed

setter and getter for var allowed: Principal

To test:
Open the demo

Query the hello method. This should give an error

Login with your II and copy your principal id

Paste in _set_allowed_principal and submit

Query the hello method

Next steps
Some more testing (hopefully local Docker testing with Selenium for local alternative origins testing)
UI touches
Gather feedback