将Microsoft.Graph与控制台应用程序一起使用

Question

I am trying to replicate the Microsoft example for using Outlook.COM with a console app. So I created a C# console app and added the needed packages:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Microsoft.Graph" version="1.5.1" targetFramework="net461" />
  <package id="Microsoft.Graph.Core" version="1.6.1" targetFramework="net461" />
  <package id="Microsoft.Identity.Client" version="1.1.0-preview" targetFramework="net461" />
  <package id="Newtonsoft.Json" version="6.0.1" targetFramework="net461" />
  <package id="System.Net.Http" version="4.3.1" targetFramework="net461" />
  <package id="System.Security.Cryptography.Algorithms" version="4.3.0" targetFramework="net461" />
  <package id="System.Security.Cryptography.Encoding" version="4.3.0" targetFramework="net461" />
  <package id="System.Security.Cryptography.Primitives" version="4.3.0" targetFramework="net461" />
  <package id="System.Security.Cryptography.X509Certificates" version="4.3.0" targetFramework="net461" />
</packages>

I amended my main console class:

using System;
using Microsoft.Identity.Client;

namespace OutlookCalIFConsole
{
    class Program
    {
        //Below is the clientId of your app registration. 
        //You have to replace the below with the Application Id for your app registration
        private static string ClientId = "xxxxx";

        public static PublicClientApplication PublicClientApp = new PublicClientApplication(ClientId);

        static void Main(string[] args)
        {
            Outlook oOutlook = new Outlook();

            oOutlook.AquireToken();
            if (oOutlook.ResultsText != "")
                Console.WriteLine(oOutlook.ResultsText);
        }
    }
}

And I created my Outlook class:

using Microsoft.Identity.Client;
using System;
using System.Linq;
using System.Threading.Tasks;

namespace OutlookCalIFConsole
{
    class Outlook
    {

        //Set the API Endpoint to Graph 'me' endpoint
        string _graphAPIEndpoint = "https://graph.microsoft.com/v1.0/me";

        //Set the scope for API call to user.read
        string[] _scopes = new string[] { "user.read" };

        public string ResultsText { get { return strResultsText; } }
        string strResultsText = "";

        public async void AquireToken()
        {
            AuthenticationResult authResult = null;

            try
            {
                if (authResult == null)
                {
                    authResult = await Program.PublicClientApp.AcquireTokenSilentAsync(_scopes, Program.PublicClientApp.Users.FirstOrDefault());
                }
            }
            catch (MsalUiRequiredException ex)
            {
                // A MsalUiRequiredException happened on AcquireTokenSilentAsync. This indicates you need to call AcquireTokenAsync to acquire a token
                System.Diagnostics.Debug.WriteLine($"MsalUiRequiredException: {ex.Message}");

                try
                {
                    authResult = await Program.PublicClientApp.AcquireTokenAsync(_scopes);
                }
                catch (MsalException msalex)
                {
                    strResultsText = $"Error Acquiring Token:{System.Environment.NewLine}{msalex}";
                }
            }
            catch (Exception ex)
            {
                strResultsText = $"Error Acquiring Token Silently:{System.Environment.NewLine}{ex}";
                return;
            }

            if (authResult != null)
            {
                strResultsText = await GetHttpContentWithToken(_graphAPIEndpoint, authResult.AccessToken);
                Console.WriteLine(strResultsText);

                DisplayBasicTokenInfo(authResult);

                SignOut();
                if (strResultsText != "")
                    Console.WriteLine(strResultsText);
            }
        }

        /// <summary>
        /// Perform an HTTP GET request to a URL using an HTTP Authorization header
        /// </summary>
        /// <param name="url">The URL</param>
        /// <param name="token">The token</param>
        /// <returns>String containing the results of the GET operation</returns>
        public async Task<string> GetHttpContentWithToken(string url, string token)
        {
            var httpClient = new System.Net.Http.HttpClient();
            System.Net.Http.HttpResponseMessage response;
            try
            {
                var request = new System.Net.Http.HttpRequestMessage(System.Net.Http.HttpMethod.Get, url);
                //Add the token in Authorization header
                request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
                response = await httpClient.SendAsync(request);
                var content = await response.Content.ReadAsStringAsync();
                return content;
            }
            catch (Exception ex)
            {
                return ex.ToString();
            }
        }

        private void DisplayBasicTokenInfo(AuthenticationResult authResult)
        {
            string strTokenInfoText = "";
            if (authResult != null)
            {
                strTokenInfoText += $"Name: {authResult.User.Name}" + Environment.NewLine;
                strTokenInfoText += $"Username: {authResult.User.DisplayableId}" + Environment.NewLine;
                strTokenInfoText += $"Token Expires: {authResult.ExpiresOn.ToLocalTime()}" + Environment.NewLine;
                strTokenInfoText += $"Access Token: {authResult.AccessToken}" + Environment.NewLine;
                Console.WriteLine(strTokenInfoText);
            }
        }

        public void SignOut()
        {
            strResultsText = "";
            if (Program.PublicClientApp.Users.Any())
            {
                try
                {
                    Program.PublicClientApp.Remove(Program.PublicClientApp.Users.FirstOrDefault());
                    Console.WriteLine("User has signed-out");
                }
                catch (MsalException ex)
                {
                    strResultsText = $"Error signing-out user: {ex.Message}";
                }
            }
        }
    }
}

The above is based on the examples for WPF. I just adapted it as I thought would be Ok for a console app. But when I run it I get an exception:

Exception thrown: 'Microsoft.Identity.Client.MsalUiRequiredException' in Microsoft.Identity.Client.dll Exception thrown: 'Microsoft.Identity.Client.MsalUiRequiredException' in mscorlib.dll Exception thrown: 'Microsoft.Identity.Client.MsalUiRequiredException' in mscorlib.dll

I have read up on MsalUiRequiredException and understandably it states:

This exception class is to inform developers that UI interaction is required for authentication to succeed.

So, how exactly am I supposed to get this to work? I thought it would show a browser control with the needed resources for the user to interact with.

I can't work out how to get it to work so that I can authenticate. According to the code it should all be OK.

Update

I tried changing:

static void Main(string[] args)
{
    Outlook oOutlook = new Outlook();

    new Task(oOutlook.AquireToken).Start();

    if (oOutlook.ResultsText != "")
        Console.WriteLine(oOutlook.ResultsText);
}

Makes no difference.

Answer 1

The problem is that AquireToken() is marked as async void which you should avoid unless it is an event handler. It is not possible to catch an exception as a result of calling an async void method.

Also, because you don't wait on the tasks created, it's entirely possible your app is exiting before the tasks complete.

One way to fix this is to have the main app create a Task and wait for it to complete. Main can't be async so you need to explicitly block on the task rather than using await .

static void Main(string[] args)
{
    var program = new Program();
    var task = Task.Run(program.Run);
    task.Wait();
}

...then add this new method to Program :

private async Task Run()
{
    Outlook oOutlook = new Outlook();
    await oOutlook.AquireToken();
    if (oOutlook.ResultsText != "")
        Console.WriteLine(oOutlook.ResultsText);
}

Change AquireToken signature from:

public async void AquireToken()

...to:

public async Task AquireToken()  

Now when you run your console app you will see the login window. Here you can see it is already picking up my cached account name:

Tell me more about async/await

• Async/Await - Best Practices in Asynchronous Programming