Active Directory Authorisation Tokens in C#

Summary

Here is a quick tip for anyone trying to get an OAuth2 JWT token from an Azure AD 2.0 endpoint.

https://login.microsoftonline.com/common/oauth2/v2.0/token

Request a JWT Token

Three pieces of information are required:

1. client_id (obtained from the app registration).
2. client_secret (obtained from the app registration).
3. scope (defaulted to all scoped below)

 public async Task GetTokenAsync()
        {
            var client = new RestClient("https://login.microsoftonline.com/common/oauth2/v2.0/token");

            var request = new RestRequest($"", Method.Get);
            request.AddHeader("Content-Type", "application/x-www-form-urlencoded");
            request.AddHeader("Cookie", "fpc=AoYuco9kc5dGkrf4E9KZpcJLV8dmAQAAABL3DtoOAAAA; stsservicecookie=estsfd; x-ms-gateway-slice=estsfd");
            request.AddParameter("grant_type", "client_credentials");
            request.AddParameter("client_id", "3000000-9b2d-488f-b587-8be16d300595");
            request.AddParameter("client_secret", "XAAAAA-_ZvALLEze6FYf2LbVACffjJ8q~i2Mar.");
            request.AddParameter("scope", "https://diskussio.onmicrosoft.com/3657a273-3560-0000-a647-b949ead0d43c/.default");

            var response = await client.PostAsync<TokenResponse>(request);
        }

record TokenResponse
   {
       [JsonPropertyName("token_type")]
       public string? TokenType { get; init; }
       [JsonPropertyName("access_token")]
       public string? AccessToken { get; init; }
   }

The response will now contain the bearer token.