Assign Claims

[bagzli]

Hi,

I'm trying to figure out how I would add claims to your project. For a simple example, I would like to attach MyCustomField that sits in the Users table. How would accomplish that? I was looking at ServiceCollectionExtension and I see you have some overrides that let you pass in TRoleClaim, but I'm not sure if this is what I'm looking for. And to be honest, I'm not sure how I would pass this along at startup.

[grandchamp]

MyCustomField is a property on User class?

[bagzli]

Yes in this instance.

[grandchamp]

The sample already do that.

Check https://github.com/grandchamp/Identity.Dapper/blob/master/samples/Identity.Dapper.Samples.Web/Entities/CustomUser.cs, there's a Address property.

And you'll have to do services.AddIdentity<CustomUser, CustomRole>.

[bagzli]

I don't think I fully understand what you mean or I may have just poorly explained what I am trying to do. Here is a better example.

In my controller, I would like to retrieve that Address field you mentioned above. I would like to do it by typing the following: HttpContext.User.Identity.GetAddress();. If you open the code, you will notice that by default, Name is already in there as part of it, but nothing else. Any other field we have to add ourselves.

When I use to work with EF6, I would do that in the following way. I would first create IIdentity extensions such as this:

   public static class IdentityExtensions
   {
       public static string GetAddress(this IIdentity identity)
       {
           return ((ClaimsIdentity) identity).FindFirst("Address").Value;
       }
   }

Now the above method only gets the value out of claims. The problem is putting the value as part of the claim. EF6 would let you do it like this:

public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager)
{

  var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);

  userIdentity.AddClaim(new Claim("CompanyId", (this.CompanyId + "" ?? "0")));

  return userIdentity;
}}

This is inside the CustomUser.cs file and I believe the internal workings of the EF6 knew to call that method and assign claims. But with dapper and your project, I am not sure how I would go about assigning the claim value.

I've looked at what you wrote above, but I can't seem to find anywhere where you Assign the Address value to the claims.

[grandchamp]

Oh, now i understand what you meant.
If you use userManager.AddClaimAsync(), when you login the Identity don't automatically generates the claim for your user?

[bagzli]

Are you saying that upon login I should retrieve the user from the database and via the UserManager assign claims at that point?

[grandchamp]

Yep.
Then you'll logout and login, check if Identity auto-fills your custom claim.

[bagzli]

I think I misunderstood you there then. If I write the code to happen on login, that will happen each time they login, there won't be any auto-fill going on, my code will be adding it each time.

[grandchamp]

I think so.

What i'm telling you is:

Somewhere your code (maybe on your register page?) you'll call userManager.AddClaimAsync() to add your custom claim to your user.

Then, i think Identity will automatically add your custom claim to your user, then you'll be able to do HttpContext.User.Identity.GetAddress().

[bagzli]

Ok, I'll experiment more this weekend. I'm wondering now what does AddClaimAsync do actually. Does it write to the database? maybe it writes to session? Anywho, I'll investigate and let you know where I'm at. Thanks for the help.

[grandchamp]

It calls userRepository.InsertClaimsAsync that will INSERT the claim on UserClaimTable.

[bagzli]

Ok then yeah this is not it. From my understanding, these claims come from the third party. The claims I am talking about are stored in memory and come from the data in the database. Because, if I have a field on User Table called Address, why would I want to copy address value into claims table, it's not right, I shouldn't duplicate my data, especially if one is bound to change eventually.

[grandchamp]

I understand your point.

Maybe this helps: http://benfoster.io/blog/customising-claims-transformation-in-aspnet-core-identity

[bagzli]

I don't have time to go through this thoroughly and write some tests to make sure, but the article seems to be on the money at the first glance, I wish I found it sooner. I'll write back here with my findings. If I end up figuring it out and its something that can benefit the project, I'll create a pull request for you and you can decide if you want it.

[grandchamp]

Well, maybe it's out of scope of this project, but surely it'll help on your personal needs.
I was thinking that it was something related to any implementation here.