Mastodon OAuth2 Provider

[OmmyZhang]

I hope gitea can configure custom OAuth2 Provider instead of only provide limited choices.
With custom authorizeUrl, tokenUrl, profileURL, scopes , subjectClaim( it's sub for oidc) and usernameTemplate, almost any OAuth2/OpenId can work. (That's how synapse porject does)

My problem is that I want to use Mastodon as OAuth2 Provider but failed, but I think this feature can be widely useful.

[techknowlogick]

OAuth2 itself is implemented with many differences between providers, we use https://github.com/markbates/goth/tree/master/providers for connecting to various providers, and as you can see there are many listed there as they are all implemented differently. If you'd like Mastodon to be implemented please open an issue/PR upstream, and once supported we'd be happy to add support.

[techknowlogick]

Re-opening as Goth now supports Mastodon as an OAuth2 provider, which means with a PR we can support Mastodon as well

[techknowlogick]

Closed per linked PR