I am working on a web app that needs to integrate with an existing user database. I would still like to use the [Authorize]
attributes, but I don\'t want to use
Creating custom authentication in ASP.NET Core can be done in a variety of ways. If you want to build off existing components (but don't want to use identity), checkout the "Security" category of docs on docs.asp.net. https://docs.asp.net/en/latest/security/index.html
Some articles you might find helpful:
Using Cookie Middleware without ASP.NET Identity
Custom Policy-Based Authorization
And of course, if that fails or docs aren't clear enough, the source code is at https://github.com/dotnet/aspnetcore/tree/master/src/Security which includes some samples.