Consume an ABP Framework API from a .NET Core console Application

Introduction

In this article I will show you how to connect to a protected ABP Framework API from a .NET Core console Application using the IdentityModel.OidcClient nuget package.

The sample BookStore ABP Framework application in this article has been developed with Blazor as UI Framework and SQL Server as database provider.

The BookStoreConsole application is a standard .NET Core console application.

As I tried to keep this article as simple as possible, you will see there is still some room for code improvements.

Source code

The source code of both projects is available on GitHub.

Requirements

The following tools are needed to be able to run the solution and follow along.

• .NET 6.0 SDK
• VsCode, Visual Studio 2019 Version 16.10.4+ or another compatible IDE

ABP Framework application

Create a new ABP Framework application

  abp new BookStore -u blazor -o BookStore

Implement the Web Application Development tutorial (part1-5)

To follow along make sure you have a protected BookAppService in the BookStore application. For this article I followed the Web Application Development tutorial till part 5: Authorization.

Add the section below in the appsettings.json file of the DbMigrator project

"BookStore_Console": {
    "ClientId": "BookStore_Console",
    "ClientSecret": "1q2w3e*",
    "RootUrl": "https://localhost:44368"
}

Add a BookStoreConsole client in the IdentityServerDataSeedContributor class of the Domain project

// BookStoreConsole Client
var bookStoreConsoleClientId = configurationSection["BookStore_Console:ClientId"];
if (!bookStoreConsoleClientId.IsNullOrWhiteSpace())
{
    var bookStoreConsoleRootUrl = configurationSection["BookStore_Console:RootUrl"].TrimEnd('/');
    await CreateClientAsync(
        name: bookStoreConsoleClientId,
        scopes: commonScopes,
        grantTypes: new[] { "password", "client_credentials""authorization_code" },
        secret: configurationSection["BookStore_Console:ClientSecret"]?.Sha256(),
        requireClientSecret: false,
        redirectUri: $"{bookStoreConsoleRootUrl}/authentication/login-callback",
    corsOrigins: new[] { bookStoreConsoleRootUrl.RemovePostFix("/") }
    );
}

Run DbMigrator project

To apply the settings above you need to run the DbMigrator project. After, you can check the IdentityServerClients table of the database to see if the BookStore_Console client has been added.

.NET Core console application

Create a new .NET Core console application

    dotnet new console -n BookStoreConsole

Install nuget packages (in terminal window or nuget package manager)

  dotnet add package IdentityModel.OidcClient --version 5.0.0-preview.1
  dotnet add package Newtonsoft.Json --version 13.0.1

Add a HttpService class in the root of the project

When you want to consume a protected API the user has to be authenticated (username+password) and authorized(has the right permissions). So, when you call the BookAppService GetListAsync method, in the header of the request you need to send the accesstoken with.

To obtain the accesstoken you can make use of the nuget package IdentityModel.OidcClient. All the heavy lifting occurs in the GetTokensFromBookStoreApi method (See below). These method sends a request to the disco.TokenEndpoint of the BookStoreApi and obtains a TokenResponse. If the correct properties are sent and the API is running, you should obtain a TokenResponse (AccessToken, IdentityToken, Scope, ...)

Afterwards the obtained accesstoken is used in the SetBearerToken() of the httpClient.

When you make a request now to the protected BookStore API with the httpClient, the accesstoken is sent with. The BookStore API receives this request and checks the validity of the accesstoken and the permissions. If these conditions are met, the GetListAsync method of the BookAppService returns the list of books.

public class HttpService
{
    public async Task<Lazy<HttpClient>> GetHttpClientAsync(bool setBearerToken)
    {
        var client = new Lazy<HttpClient>(() => new HttpClient());
        var accessToken = await GetAccessToken();
        if (setBearerToken)
        {
            client.Value.SetBearerToken(accessToken);
        }
        client.Value.BaseAddress = new Uri("https://localhost:44388/"); //
        return await Task.FromResult(client);
    }

    private static async Task<TokenResponse> GetTokensFromBookStoreApi()
    {
        var authority = "https://localhost:44388/";
        var discoveryCache = new DiscoveryCache(authority);
        var disco = await discoveryCache.GetAsync();
        var httpClient = new Lazy<HttpClient>(() => new HttpClient());
        var response = await httpClient.Value.RequestPasswordTokenAsync(new PasswordTokenRequest
        {
            Address = disco.TokenEndpoint, // https://localhost:44388/connect/token
            ClientId = "BookStore_Console",
            ClientSecret = "1q2w3e",
            UserName = "admin",
            Password = "1q2w3E*",
            Scope = "email openid profile role phone address BookStore",
        });
        if (response.IsError) throw new Exception(response.Error);
        return response;
    }

    private async Task<string> GetAccessToken()
    {
        var accessToken = (await GetTokensFromBookStoreApi()).AccessToken;
        return accessToken;
    }

}

Main Method

Below you see the Main method of the Program.cs file. A new HttpService gets created and the GetHttpClientAsync method is called to get a httpClient.

Next, we make a request to the BookStore API to obtain the list of books.

static async Task Main()
{
    // if setBearerToken = false, should throw HttpRequestException: 'Response status code does not indicate success: 401 (Unauthorized).'
    // if setBearerToken = true, API should be called an list of books should be returned
    const bool setBearerToken = true;

    var httpService = new HttpService();
    var httpClient = await httpService.GetHttpClientAsync(setBearerToken);

    var response = await httpClient.Value.GetAsync("https://localhost:44388/api/app/book");
    response.EnsureSuccessStatusCode();

    var json = await response.Content.ReadAsStringAsync();

    var books = JsonConvert.DeserializeObject<ListResultDto<BookDto>>(json);

    Console.WriteLine("====================================");
    if (books?.Items != null)
        foreach (var book in books.Items)
            Console.WriteLine(book.Name);
    Console.WriteLine("====================================");
    Console.ReadKey();
}

Run API and .NET Core console application

Run the BookStore.HttpApi.Host of the ABP Framework application first. Start the .NET Core console application next. Below is the result when the accesstoken is successfully set.

If you set the variable setBearerToken in the Main method to false, you will get a 401 (Unauthorized)

Congratulations, you can now connect to an ABP Framework API form a .NET Core console application! Check out the source code of this article on GitHub.

Enjoy and have fun!