How to generate Azure Active Directory (AAD) authentication token for Graph API without interactive login screen for console/native application?

Question

How to generate Azure Active Directory (AAD) authentication token for Graph API without interactive login screen for console/native application?

Details: I am using Graph API to read emails with Azure Active Directory (AAD) with ‘’Delegated’’ permissions.

”Application” permission allows a user to read other mailboxes and there is no admin consent for this approach due to security concerns, so I am using ‘’Delegated’’ permissions.

My console/native application is registered to AAD.

Since AAD generates OAuth Authentication token for a specific account using: 1. Client ID 2. Tenant ID 3. Client Secret (Key/password for the application) 4. Login credentials of a specific account.

I can generate a token using an interactive login screen.

However, I want a mechanism where I can generate AAD token for Graph API (resource) without an interactive login screen within code using C# or.NET

Answer 1

Its seems you are trying to get your token without prompting the sign in page.

Yeah, you can do it using client_credentials grant authentication flow within C#.Net

See the following code snippet:

Access Token Class:

 public  class AccessTokenClass
        {
            public string access_token { get; set; }
            public string token_type { get; set; }
            public long expires_in { get; set; }
        }

Token Request Method:

private async Task<string> GetYourTokenWithClientCredentialsFlow()
        {
            string tokenUrl = $"https://login.microsoftonline.com/YourTenant/oauth2/token";
            var tokenRequest = new HttpRequestMessage(HttpMethod.Post, tokenUrl);

            tokenRequest.Content = new FormUrlEncodedContent(new Dictionary<string, string>
            {
                ["grant_type"] = "client_credentials",
                ["client_id"] = "5f14dea0-5cd---Your_Client_Id----8950-4f646829f870",
                ["client_secret"] = "031Fnwih---Your_Client_Secret----Fx+Ase3V65lpWQ=",
                ["resource"] = "https://graph.microsoft.com" // https://management.azure.com/ Or Any Resource You Want
            });

            dynamic json;
            dynamic token;
            HttpClient client = new HttpClient();

            var tokenResponse = await client.SendAsync(tokenRequest);

            json = await tokenResponse.Content.ReadAsStringAsync();
            token = JsonConvert.DeserializeObject<AccessTokenClass>(json);
            Console.WriteLine("Your Access Token {0}",token.access_token);
            return token;
        }

Generated Token Response:

Once you have set all of your required credentials you would get the token in response. See the screen shot below:

Note: This authentication flow would generate token for you without interactive login screen. If you still have any query feel free to share in comment. Thanks and happy coding!

Update:

To assign dedicated permission for reading mail. Follow the below steps:

1. Azure active directory
2. App registration
3. Select your app
4. API permissions
5. Add a permission
6. Microsoft graph
7. Delegated permissions
8. Mail
9. Mail.Read (read user mail)
10. Add permission
11. Grant admin consent

See the screen shot: