Incomplete social login for Twitter results in 404

[stevejgordon]

If you don't fully complete the social login registration (test with Twitter but may affect other services) it's possible to get into a position where you cannot use that provider any longer.

Steps to reproduce:

• Ensure you have user-secrets setup for Twitter with a valid key and secret
• On the login page choose to login with Twitter
• On redirect you will be taken to a page to complete your name and email etc.
• Navigate away from this page, without completing the process
• Go back to the login screen and choose Twitter again.
• You will get a 404 error from the site

The local solution is to delete the cookies for the site which removes the Identity.External cookie and allows you to retry the process.

The flow of the site may need review to see if we can prevent this situation.

[BillWagner]

Adding ready issues to the Dec V1 milestone.

[shahiddev]

@BillWagner I'll take a look at this

[shahiddev]

FYI for anyone trying to setup twitter auth for testing, you need to provide a url for callback in the twitter even though its not a mandatory field. Without this you'll run into a 401 error before you even see the consent screen

[shahiddev]

@stevejgordon I can't seem to reproduce this exactly as you've described. If I cancel or navigate away from the twitter consent screen and then return to AllReady login screen and try Twitter again it works as expected.

However if/when I press the cancel button it gives me an option to return back to AllReady page, that currently fails.

I have a potential solution for this

[shahiddev]

There a couple of fixes involved here, the original issue actually occurred after user has given consent in social medial login screen and is returned back to the externallogin callback to complete registration. Cancelling here does indeed cause an issue, it appears to be linked to the issue described here aspnet/Identity#915 (comment)
The fix described in there involved updating the account controller to clear external login cookies when trying to login.