As example of implementation https://productpains.com/post/keystonejs/integrate-passport-as-authentication-middleware

I'm currently working on a project that integrates keystone into a loopback application (extensive framework around express). With that, I've developed a component (https://www.npmjs.com/package/loopback-component-auth) that supports all varieties of passport strategies as authentication providers, automatically mounted into your express / loopback app.

Now, keystone relies on authentication being handled in a separate middleware and thus doesn't need to worry how the user got authenticated.

Related to that approach, I opened another feature request (https://productpains.com/post/keystonejs/token-authentication). Maybe we can bring both topics together and find a solution that satisfies all the related pain.

Business requirement at my workplace :)

This would be less important if Keystone Social Plugin worked with latest 0.3x release