IdentityServer4 register UserService and get users from database in asp.net core

Question

I've searched all over on how to register a UserService with IdentityServer4 in asp.net core, but I cant seem to find the right way to do it.

This is the code to register InMemoryUsers found here, however I would like to access users from my MSSQL DB not static users defined in the sample.

var builder = services.AddIdentityServer(options =>
{
    options.SigningCertificate = cert;
});

builder.AddInMemoryClients(Clients.Get());
builder.AddInMemoryScopes(Scopes.Get());
builder.AddInMemoryUsers(Users.Get());

So then I looked at this which is for IdentityServer3.

var factory = new IdentityServerServiceFactory()
                .UseInMemoryClients(Clients.Get())
                .UseInMemoryScopes(Scopes.Get());

var userService = new UserService();
factory.UserService = new Registration<IUserService>(resolver => userService);

From reading online it seems I need to use the DI system to register the UserService, but I'm not sure how it binds to the IdentityServer eg.

services.AddScoped<IUserService, UserService>();

So my question is:

How do I bind my UserService to the builder (IdentityServer4 Users)? And how would I go about calling my database to access and authenticate my existing db users in the UserService (I use repositories to connect to db)?

Taking into account this has to work with asp.net core.

Thanks!

Answer 1

Update - IdentityServer 4 has changed and replaced IUserService with IResourceOwnerPasswordValidator and IProfileService

I used my UserRepository to get all the user data from the database. This is injected (DI) into the constructors, and defined in Startup.cs. I also created the following classes for identity server (which is also injected):

First define ResourceOwnerPasswordValidator.cs:

public class ResourceOwnerPasswordValidator : IResourceOwnerPasswordValidator
{
    //repository to get user from db
    private readonly IUserRepository _userRepository;

    public ResourceOwnerPasswordValidator(IUserRepository userRepository)
    {
        _userRepository = userRepository; //DI
    }

    //this is used to validate your user account with provided grant at /connect/token
    public async Task ValidateAsync(ResourceOwnerPasswordValidationContext context)
    {
        try
        {
            //get your user model from db (by username - in my case its email)
            var user = await _userRepository.FindAsync(context.UserName);
            if (user != null)
            {
                //check if password match - remember to hash password if stored as hash in db
                if (user.Password == context.Password) {
                    //set the result
                    context.Result = new GrantValidationResult(
                        subject: user.UserId.ToString(),
                        authenticationMethod: "custom", 
                        claims: GetUserClaims(user));

                    return;
                } 

                context.Result = new GrantValidationResult(TokenRequestErrors.InvalidGrant, "Incorrect password");
                return;
            }
            context.Result = new GrantValidationResult(TokenRequestErrors.InvalidGrant, "User does not exist.");
            return;
        }
        catch (Exception ex)
        {
            context.Result = new GrantValidationResult(TokenRequestErrors.InvalidGrant, "Invalid username or password");
        }
    }
    
    //build claims array from user data
    public static Claim[] GetUserClaims(User user)
    {
        return new Claim[]
        {
            new Claim("user_id", user.UserId.ToString() ?? ""),
            new Claim(JwtClaimTypes.Name, (!string.IsNullOrEmpty(user.Firstname) && !string.IsNullOrEmpty(user.Lastname)) ? (user.Firstname + " " + user.Lastname) : ""),
            new Claim(JwtClaimTypes.GivenName, user.Firstname  ?? ""),
            new Claim(JwtClaimTypes.FamilyName, user.Lastname  ?? ""),
            new Claim(JwtClaimTypes.Email, user.Email  ?? ""),
            new Claim("some_claim_you_want_to_see", user.Some_Data_From_User ?? ""),

            //roles
            new Claim(JwtClaimTypes.Role, user.Role)
        };
}

And ProfileService.cs:

public class ProfileService : IProfileService
{
    //services
    private readonly IUserRepository _userRepository;

    public ProfileService(IUserRepository userRepository)
    {
        _userRepository = userRepository;
    }

    //Get user profile date in terms of claims when calling /connect/userinfo
    public async Task GetProfileDataAsync(ProfileDataRequestContext context)
    {
        try
        {
            //depending on the scope accessing the user data.
            if (!string.IsNullOrEmpty(context.Subject.Identity.Name))
            {
                //get user from db (in my case this is by email)
                var user = await _userRepository.FindAsync(context.Subject.Identity.Name);

                if (user != null)
                {
                    var claims = GetUserClaims(user);

                    //set issued claims to return
                    context.IssuedClaims = claims.Where(x => context.RequestedClaimTypes.Contains(x.Type)).ToList();
                }
            }
            else
            {
                //get subject from context (this was set ResourceOwnerPasswordValidator.ValidateAsync),
                //where and subject was set to my user id.
                var userId = context.Subject.Claims.FirstOrDefault(x => x.Type == "sub");

                if (!string.IsNullOrEmpty(userId?.Value) && long.Parse(userId.Value) > 0)
                {
                    //get user from db (find user by user id)
                    var user = await _userRepository.FindAsync(long.Parse(userId.Value));

                    // issue the claims for the user
                    if (user != null)
                    {
                        var claims = ResourceOwnerPasswordValidator.GetUserClaims(user);

                        context.IssuedClaims = claims.Where(x => context.RequestedClaimTypes.Contains(x.Type)).ToList();
                    }
                }
            }
        }
        catch (Exception ex)
        {
            //log your error
        }
    }

    //check if user account is active.
    public async Task IsActiveAsync(IsActiveContext context)
    {
        try
        {
            //get subject from context (set in ResourceOwnerPasswordValidator.ValidateAsync),
            var userId = context.Subject.Claims.FirstOrDefault(x => x.Type == "user_id");

            if (!string.IsNullOrEmpty(userId?.Value) && long.Parse(userId.Value) > 0)
            {
                var user = await _userRepository.FindAsync(long.Parse(userId.Value));

                if (user != null)
                {
                    if (user.IsActive)
                    {
                        context.IsActive = user.IsActive;
                    }
                }
            }
        }
        catch (Exception ex)
        {
            //handle error logging
        }
    }
}

Then in Startup.cs I did the following:

public void ConfigureServices(IServiceCollection services)
{
    //...

    //identity server 4 cert
    var cert = new X509Certificate2(Path.Combine(_environment.ContentRootPath, "idsrv4test.pfx"), "your_cert_password");

    //DI DBContext inject connection string
    services.AddScoped(_ => new YourDbContext(Configuration.GetConnectionString("DefaultConnection")));

    //my user repository
    services.AddScoped<IUserRepository, UserRepository>();

    //add identity server 4
    services.AddIdentityServer()
        .AddSigningCredential(cert)
        .AddInMemoryIdentityResources(Config.GetIdentityResources()) //check below
        .AddInMemoryApiResources(Config.GetApiResources())
        .AddInMemoryClients(Config.GetClients())
        .AddProfileService<ProfileService>();

    //Inject the classes we just created
    services.AddTransient<IResourceOwnerPasswordValidator, ResourceOwnerPasswordValidator>();
    services.AddTransient<IProfileService, ProfileService>();

    //...
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    //...

    app.UseIdentityServer();

    JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Clear();

    IdentityServerAuthenticationOptions identityServerValidationOptions = new IdentityServerAuthenticationOptions
    {
        //move host url into appsettings.json
        Authority = "http://localhost:50000/",
        ApiSecret = "secret",
        ApiName = "my.api.resource",
        AutomaticAuthenticate = true,
        SupportedTokens = SupportedTokens.Both,

        // required if you want to return a 403 and not a 401 for forbidden responses
        AutomaticChallenge = true,

        //change this to true for SLL
        RequireHttpsMetadata = false
    };

    app.UseIdentityServerAuthentication(identityServerValidationOptions);

    //...
}

You will also need Config.cs which defines your clients, api's and resources. You can find an example here: https://github.com/IdentityServer/IdentityServer4.Demo/blob/master/src/IdentityServer4Demo/Config.cs

You should now be able to call IdentityServer /connect/token

For any further info, please check the documentation: https://media.readthedocs.org/pdf/identityserver4/release/identityserver4.pdf

---

Old answer (this does not work for newer IdentityServer4 anymore)

Its pretty simple once you understand the flow of things.

Configure your IdentityService like this (in Startup.cs - ConfigureServices()):

var builder = services.AddIdentityServer(options =>
{
    options.SigningCertificate = cert;
});

builder.AddInMemoryClients(Clients.Get());
builder.AddInMemoryScopes(Scopes.Get());

//** this piece of code DI's the UserService into IdentityServer **
builder.Services.AddTransient<IUserService, UserService>();

//for clarity of the next piece of code
services.AddTransient<IUserRepository, UserRepository>();

Then setup your UserService

public class UserService : IUserService
{
    //DI the repository from Startup.cs - see previous code block
    private IUserRepository _userRepository;

    public UserService(IUserRepository userRepository)
    {
        _userRepository = userRepository;
    }

    public Task AuthenticateLocalAsync(LocalAuthenticationContext context)
    {
        var user = _userRepository.Find(context.UserName);

        //check if passwords match against user column 
        //My password was hashed, 
        //so I had to hash it with the saved salt first and then compare.
        if (user.Password == context.Password)
        {
            context.AuthenticateResult = new AuthenticateResult(
                user.UserId.ToString(),
                user.Email,

                //I set up some claims 
                new Claim[]
                {
                    //Firstname and Surname are DB columns mapped to User object (from table [User])
                    new Claim(Constants.ClaimTypes.Name, user.Firstname + " " + user.Surname),
                    new Claim(Constants.ClaimTypes.Email, user.Email),
                    new Claim(Constants.ClaimTypes.Role, user.Role.ToString()),
                    //custom claim
                    new Claim("company", user.Company)
                }
            );
        }

        return Task.FromResult(0);
    }

    public Task GetProfileDataAsync(ProfileDataRequestContext context)
    {
        //find method in my repository to check my user email
        var user = _userRepository.Find(context.Subject.Identity.Name);

        if (user != null)
        {
            var claims = new Claim[]
                {
                    new Claim(Constants.ClaimTypes.Name, user.Firstname + " " + user.Surname),
                    new Claim(Constants.ClaimTypes.Email, user.Email),
                    new Claim(Constants.ClaimTypes.Role, user.Role.ToString(), ClaimValueTypes.Integer),
                    new Claim("company", user.Company)
            };

            context.IssuedClaims = claims.Where(x => context.RequestedClaimTypes.Contains(x.Type));
        }

        return Task.FromResult(0);
    }

    public Task IsActiveAsync(IsActiveContext context)
    {
        var user = _userRepository.Find(context.Subject.Identity.Name);

        return Task.FromResult(user != null);
    }
}

Basically by injecting UserService into builder (of type IdentityServerBuilder) Services, allows it to call the UserService on auth.

Answer 2

In IdentityServer4. IUserService is not available anymore, now you have to use IResourceOwnerPasswordValidator to do the authentication and to use IProfileService to get the claims.

In my scenario, I use resource owner grant type, and all I need is to get users' claims to do role based authorization for my Web APIs according to the username and password. And I assumed that the subject is unique for every user.

I have posted my code below, and it can work properly; could anyone tell me that is there any issues about my code?

Register these two services in the startup.cs.

public void ConfigureServices(IServiceCollection services)
{
    var builder = services.AddIdentityServer();
    builder.AddInMemoryClients(Clients.Get());
    builder.AddInMemoryScopes(Scopes.Get());
    builder.Services.AddTransient<IResourceOwnerPasswordValidator, ResourceOwnerPasswordValidator>();
    builder.Services.AddTransient<IProfileService, ProfileService>();
}

Implement the IResourceOwnerPasswordValidator interface.

public class ResourceOwnerPasswordValidator: IResourceOwnerPasswordValidator
{
    public Task<customgrantvalidationresult> ValidateAsync(string userName, string password, ValidatedTokenRequest request)
    {
        // Check The UserName And Password In Database, Return The Subject If Correct, Return Null Otherwise
        // subject = ......
        if (subject == null)
        {
            var result = new CustomGrantValidationResult("Username Or Password Incorrect");
            return Task.FromResult(result);
        }
        else {
            var result = new CustomGrantValidationResult(subject, "password");
            return Task.FromResult(result);
        }
    }
}

Implement the ProfileService interface.

public class ProfileService : IProfileService
{
    public Task GetProfileDataAsync(ProfileDataRequestContext context)
    {
        string subject = context.Subject.Claims.ToList().Find(s => s.Type == "sub").Value;
        try
        {
            // Get Claims From Database, And Use Subject To Find The Related Claims, As A Subject Is An Unique Identity Of User
            //List<string> claimStringList = ......
            if (claimStringList == null)
            {
                return Task.FromResult(0);
            }
            else {
                List<Claim> claimList = new List<Claim>();
                for (int i = 0; i < claimStringList.Count; i++)
                {
                    claimList.Add(new Claim("role", claimStringList[i]));
                }
                context.IssuedClaims = claimList.Where(x => context.RequestedClaimTypes.Contains(x.Type));
                return Task.FromResult(0);
            }
        }
        catch
        {
            return Task.FromResult(0);
        }
    }

    public Task IsActiveAsync(IsActiveContext context)
    {
        return Task.FromResult(0);
    }
}

Answer 3

In IdentityServer4 1.0.0-rc5 neither IUserService nor CustomGrantValidationResult is available.

Now instead of returning an CustomGrantValidationResult you will need to set the context.Result.

 public class ResourceOwnerPasswordValidator: IResourceOwnerPasswordValidator
 {
    private MyUserManager _myUserManager { get; set; }
    public ResourceOwnerPasswordValidator()
    {
        _myUserManager = new MyUserManager();
    }

    public async Task ValidateAsync(ResourceOwnerPasswordValidationContext context)
    {
        var user = await _myUserManager.FindByNameAsync(context.UserName);
        if (user != null && await _myUserManager.CheckPasswordAsync(user,context.Password))
        {
             context.Result = new GrantValidationResult(
                 subject: "2", 
                 authenticationMethod: "custom", 
                 claims: someClaimsList);


        }
        else
        {
             context.Result = new GrantValidationResult(
                    TokenRequestErrors.InvalidGrant,
                    "invalid custom credential");
         }


        return;

   }

Resource Owner Password Validation