Ok, the situation is this.
We already have an existing ASP.NET MVC 5 site with Custom Forms Authentication, Logon, Registration etc with a custom database for roles and profiles already implemented.
We now are adding some new functionality to the MVC site and we decided to use Web Api 2 OData 3 endpoint which lives in another domain. The Web Api currently doesn't include any authentication but we need to be able to map the requests to a certain user to get his roles etc from the backend. The MVC and API sites use the same backend.
What we would like to accomplish is, that when the user logs on in the MVC site, the MVC site calls the Web Api server-to-server with the user's credentials and receives a token that the client can then use to call the web service with.
When API receives a request with the token, it can then map the request with the user in backend and do authorization.
As far as I understand it, Simple Web Token (SWT) could pull it through. But considering the environment, .NET 4.5.1 / Web Api 2 / OData 3 with Entity Framework in Azure Web Role, I started thinking is this SWT something I should really use or if there is any NEW technologies recently published that could easily pull this through. I don't want to add any unnecessary 3rd party dependencies to the project if the .NET stack already contains something like it.
So, what would be the simplest way of pulling this kind of authentication through without adding unnecessary dependencier to the project.
The solution we are looking for, is only temporary meanwhile we redesign our authentication scheme. So we are looking for something really simple to implement that works with least dependencies that need to be removed later on.
I'm using this in a project I'm currently working on. I use the OAuth 2.0 OWIN Middleware component that ships with Web API 2.0 (if you add a new Web API project with Authentication enabled, it includes the base infrastructure).
You would use the Resource Owner Password Flow as defined in the OAuth 2.0 specification. Basically you request a Token from the Web API OWIN Middleware sending:
And in response you get a bearer token. The token generating is based upon a claims principal, the OAuth middleware component has predefined hooks for adding claims. This token now needs to be added as authorisation header to each response. On the MVC side you might add this to session so that it's always available to make backend API calls in the context of the user associated with an incoming HTTP request. If you're using WCF Data Services Client, you'll need an authorisation service/manager or similar that you can hook into OnRequestSending and OnResponseReceived events, so that you can insert that bearer token into the HTTP headers.
You can customise the OAuth Middleware component as you need to quite easily, it took a bit of time to figure it out as it's not too well documented, but downloading the Katana source code did help a bit as the source code does have some good documentation.
The nice thing about it all is that you simply need to enable HostAuthenticationFilter and add Authorize attributes on the Web API side and it's ready to go. You can get access to the claims principal object and use claims as identifying pieces of information for your user - e.g. identity, roles, other attributes etc.
To get started, look at http://www.asp.net/vnext/overview/authentication/individual-accounts-in-aspnet-web-api
Also as a wrap, I did consider the use of JSON Web Tokens (JWTs) as there is an OWIN library available for generating and parsing these. The use case here would be that you authenticate, get a JWT back, and then use the JWT to get an OAuth 2.0 bearer token. The JWT is useful if you want to move authentication elsewhere, or if you want to get additional information about the user at the MVC side of things.