Introduction

Identity Server is an open source OpenID Connect and OAuth 2.0 framework. It can be used to make your application an authentication / single sign on server. It can also issue access tokens for 3rd party clients. This document describes how you can integrate IdentityServer4 (version 2.0+) to your project.

Startup Project

This document assumes that you have already created an ASP.NET Core based project (including Module Zero) from the startup templates and have set it up to work. We created an ASP.NET Core MVC startup project for this demonstration.

Installation

There are two NuGet packages:

• Abp.ZeroCore.IdentityServer4.vNext is the main integration package.
• Abp.ZeroCore.IdentityServer4.vNext.EntityFrameworkCore is the storage provider for EF Core.

Since the EF Core package already depends on the first one, you only have to install the Abp.ZeroCore.IdentityServer4.vNext.EntityFrameworkCore package to your project. Install it to the project that contains your DbContext (.EntityFrameworkCore project for default templates):

Install-Package Abp.ZeroCore.IdentityServer4.vNext.EntityFrameworkCore

Then you can add a dependency to your module (generally, to your EntityFrameworkCore project):

[DependsOn(typeof(AbpZeroCoreIdentityServervNextEntityFrameworkCoreModule))]
public class MyModule : AbpModule
{
    //...
}

Configuration

Configuring and using IdentityServer4 with Abp.ZeroCore is similar to independently using IdentityServer4. You should read its own documentation to better understand how it works. In this document, we only show the additional configuration needed to integrate it into Abp.ZeroCore.

Startup Class

In the ASP.NET Core Startup class, we must add IdentityServer to the service collection and to the ASP.NET Core middleware pipeline. Highlighted, here are the differences from the standard IdentityServer4 usage:

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

        services.AddIdentityServer()
            .AddDeveloperSigningCredential()
            .AddInMemoryIdentityResources(IdentityServerConfig.GetIdentityResources())
            .AddInMemoryApiScopes(IdentityServerConfig.GetApiScopes())
            .AddInMemoryApiResources(IdentityServerConfig.GetApiResources())
            .AddInMemoryClients(IdentityServerConfig.GetClients())
            .AddAbpPersistedGrants<IAbpPersistedGrantDbContext>()
            .AddAbpIdentityServer<User>();

        //...
    }

    public void Configure(IApplicationBuilder app)
    {
        //...

            app.UseJwtTokenMiddleware("IdentityBearer");
            app.UseIdentityServer();

        //...
    }
}

We added services.AddIdentityServer() just after IdentityRegistrar.Register(services) and added app.UseJwtTokenMiddleware("IdentityBearer") just after app.UseAuthentication() in the startup project.

IdentityServerConfig Class

We have used the IdentityServerConfig class to get identity resources, api resources and clients. You can find more information about this class in its own documentation. For the simplest case, it can be a static class like below:

public static class IdentityServerConfig
{
    public static IEnumerable<IdentityResource> GetIdentityResources()
    {
        return new List<IdentityResource>
        {
            new IdentityResources.OpenId(),
            new IdentityResources.Profile(),
            new IdentityResources.Email(),
            new IdentityResources.Phone()
        };
    }

    public static IEnumerable<ApiScope> GetApiScopes()
    {
        return new List<ApiScope>
        {
            new ApiScope("default-api-scope")
        };
    }

    public static IEnumerable<ApiResource> GetApiResources()
    {
        return new List<ApiResource>
        {
            new ApiResource("default-api-resource", "Default (all) API")
            {
                Scopes = { "default-api-scope" }
            }
        };
    }

    public static IEnumerable<Client> GetClients()
    {
        return new List<Client>
        {
            new Client
            {
                ClientId = "client",
                AllowedGrantTypes = GrantTypes.ClientCredentials.Union(GrantTypes.ResourceOwnerPassword).ToList(),
                AllowedScopes = {"default-api-scope"},
                ClientSecrets =
                {
                    new Secret("secret".Sha256())
                }
            }
        };
    }
}

DbContext Changes

The AddAbpPersistedGrants() method is used to save consent responses to the persistent data store. In order to use it, YourDbContext must implement the IAbpPersistedGrantDbContext interface as shown below:

public class YourDbContext : AbpZeroDbContext<Tenant, Role, User, YourDbContext>, IAbpPersistedGrantDbContext
{
    public DbSet<PersistedGrantEntity> PersistedGrants { get; set; }

    public YourDbContext(DbContextOptions<YourDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.ConfigurePersistedGrantEntity();
    }
}

The IAbpPersistedGrantDbContext interface defines the PersistedGrants DbSet. We also must call the modelBuilder.ConfigurePersistedGrantEntity() extension method as shown above in order to configure EntityFramework for the PersistedGrantEntity.

Note that this change in YourDbContext causes a new database migration. So remember to use the "Add-Migration" and "Update-Database" commands to update your database.

IdentityServer4 will continue to work even if you don't call the AddAbpPersistedGrants<YourDbContext>() extension method, but user consent responses will be stored in an in-memory data store in that case (which is cleared when you restart your application!).

JWT Authentication Middleware

If we want to authorize clients against the same application we can use the IdentityServer authentication middleware for that.

First, install the IdentityServer4.AccessTokenValidation package from NuGet to your project:

Install-Package IdentityServer4.AccessTokenValidation

We can then add the middleware to the Startup class as shown below:

services.AddAuthentication().AddIdentityServerAuthentication("IdentityBearer", options =>
{
    options.Authority = "https://localhost:44388/";
    options.RequireHttpsMetadata = false;
});

We added this just after the services.AddIdentityServer() line in the startup project.

Testing

Our identity server is now ready to get requests from clients. We can create a console application to make requests and get responses.

• Create a new Console Application inside your solution.
• Add the IdentityModel NuGet package to the console application. This package is used to create clients for OAuth endpoints.

While the IdentityModel NuGet package is enough to create a client and consume your API, we need to use the API in a more type safe way: We will convert incoming data to DTOs which are returned by the application services.

• Add a reference to the Application layer from the console application. This will allow us to use the same DTO classes returned by the application layer on the client-side.
• Add the Abp.Web.Common NuGet package. This will allow us to use the AjaxResponse class defined in ASP.NET Boilerplate. Otherwise, we will have to deal with raw JSON strings to handle the server response.

Change Program.cs as shown below:

using System;
using System.Net.Http;
using System.Threading.Tasks;
using Abp.Application.Services.Dto;
using Abp.Web.Models;
using IdentityModel.Client;
using Newtonsoft.Json;

namespace IdentityServerIntegrationDemo.ConsoleApiClient
{
    class Program
    {
        static void Main(string[] args)
        {
            RunDemoAsync().Wait();
            Console.ReadLine();
        }

        public static async Task RunDemoAsync()
        {
            var accessToken = await GetAccessTokenViaOwnerPasswordAsync();
            await GetUsersListAsync(accessToken);
        }

        private static async Task<string> GetAccessTokenViaOwnerPasswordAsync()
        {
            var disco =  await new HttpClient().GetDiscoveryDocumentAsync("https://localhost:44388");

            var tokenClient = new HttpClient();
            tokenClient.DefaultRequestHeaders.Add("Abp.TenantId", "1");
            var tokenResponse = await tokenClient.RequestPasswordTokenAsync(new PasswordTokenRequest()
            {
                Address = disco.TokenEndpoint,
                ClientId = "client",
                ClientSecret = "secret",
                UserName = "admin",
                Password = "123qwe"
            });

            if (tokenResponse.IsError)
            {
                Console.WriteLine("Error: ");
                Console.WriteLine(tokenResponse.Error);
            }

            Console.WriteLine(tokenResponse.Json);

            return tokenResponse.AccessToken;
        }

        private static async Task GetUsersListAsync(string accessToken)
        {
            var client = new HttpClient();
            client.SetBearerToken(accessToken);

            var response = await client.GetAsync("https://localhost:44388/api/services/app/user/GetAll");
            if (!response.IsSuccessStatusCode)
            {
                Console.WriteLine(response.StatusCode);
                return;
            }

            var content = await response.Content.ReadAsStringAsync();
            var ajaxResponse = JsonConvert.DeserializeObject<AjaxResponse<PagedResultDto<UserListDto>>>(content);
            if (!ajaxResponse.Success)
            {
                throw new Exception(ajaxResponse.Error?.Message ?? "Remote service throws exception!");
            }

            Console.WriteLine();
            Console.WriteLine("Total user count: " + ajaxResponse.Result.TotalCount);
            Console.WriteLine();
            foreach (var user in ajaxResponse.Result.Items)
            {
                Console.WriteLine($"### UserId: {user.Id}, UserName: {user.UserName}");
                Console.WriteLine(JsonConvert.SerializeObject(user, Formatting.Indented));
            }
        }
    }

    internal class UserListDto
    {
        public int Id { get; set; }
        public string UserName { get; set; }
    }
}

Before running this application, ensure that your web project set up and running, because this console application will make a request to the web application. Also, ensure that the requesting port (44388) is the same as your web application.