How to add claims to access token get from IdentityServer3 using resource owner flow with javascript client

Question

I use the resource owner flow with IdentityServer3 and send get token request to identity server token endpoint with username and password in javascript as below:

Answer 1

I have just spent a while figuring this out myself. @leastprivilege's comment on Yang's answer had the clue, this answer is just expanding on it.
It's all down to how the oAuth and OIDC specs evolved, it's not an artefact of IdentityServer (which is awesome). Firstly, here is a fairly decent discussion of the differences between identity tokens and access tokens: https://github.com/IdentityServer/IdentityServer3/issues/2015 which is worth a read.

With Resource Owner flow, like you are doing, you will always get an Access Token. By default and per the spec, you shouldn't include claims in that token (see the above link for why). But, in practice, it is very nice when you can; it saves you extra effort on both client and server.

What Leastprivilege is referring to is that you need to create a scope, something like this:

new Scope
{
    Name = "member",
    DisplayName = "member",
    Type = ScopeType.Resource,

    Claims = new List
        {
              new ScopeClaim("role"),
              new ScopeClaim(Constants.ClaimTypes.Name),
              new ScopeClaim(Constants.ClaimTypes.Email)
        },

    IncludeAllClaimsForUser = true
}

And then you need to request that scope when you ask for the token. I.e. your line scope: "openid profile roles", should change to scope: "member", (well, I say that - scopes play a dual role here, as far as I can see - they are also a form of control, i.e. the client is asking for certain scopes and can be rejected if it is not allowed those but that is another topic).

Note the important line that eluded me for a while, which is Type = ScopeType.Resource (because Access Tokens are about controlling access to resources). This means it will apply to Access Tokens and the specified claims will be included in the token (I think, possibly, against spec but wonderfully).

Finally, in my example I have included both some specific claims as well as IncludeAllClaimsForUser which is obviously silly, but just wanted to show you some options.