EWS MSAL Modern Authentication

gistfile1.txt

ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2013_SP1);
String ClientId = "111111-52b3-4102-aeff-aad2292ab01c";
String MailboxName = "gscales@datarumble.com";
HttpClient httpClient = new HttpClient();
httpClient.DefaultRequestHeaders.UserAgent.ParseAdd("Mozilla/5.0 (compatible; AcmeInc/1.0)");
StringContent RealmRequest = new StringContent("{\"username\":\"" + MailboxName + "\"}");
String DiscoveryURL = "https://login.microsoftonline.com/common/GetCredentialType";
dynamic RealmDiscover = JsonConvert.DeserializeObject(httpClient.PostAsync(DiscoveryURL, RealmRequest).Result.Content.ReadAsStringAsync().Result);
if((Int32)RealmDiscover.EstsProperties.DomainType == 1 || (Int32)RealmDiscover.EstsProperties.DomainType == 2)
{
	service.Credentials = new WebCredentials("user1@contoso.com", "password");
	service.AutodiscoverUrl("user1@contoso.com", RedirectionUrlValidationCallback);
}
else
{
    String AutoDiscoverEndpoint = $"https://outlook.office365.com/autodiscover/autodiscover.json/v1.0/{MailboxName}?Protocol=EWS";
	dynamic JsonResult = JsonConvert.DeserializeObject(httpClient.GetAsync(AutoDiscoverEndpoint).Result.Content.ReadAsStringAsync().Result);
	if (IsPropertyExist(JsonResult, "Url"))
	{
		String AudienceHostName = new Uri(JsonResult.Url.ToString()).Host;
		string scope = "https://" + AudienceHostName + "/EWS.AccessAsUser.All";
		PublicClientApplicationBuilder pcaConfig = PublicClientApplicationBuilder.Create(ClientId).WithAuthority(AadAuthorityAudience.AzureAdMultipleOrgs);
		var IntToken = pcaConfig.Build().AcquireTokenInteractive(new[] { scope }).ExecuteAsync().Result;
		service.Credentials = new OAuthCredentials(IntToken.AccessToken);
		service.Url = new Uri(JsonResult.Url.ToString());
	}
}
Folder Inbox = Folder.Bind(service, WellKnownFolderName.Inbox);

}
public static bool IsPropertyExist(dynamic settings, string name)
{
	if (settings is Newtonsoft.Json.Linq.JObject)
		return ((Newtonsoft.Json.Linq.JObject)settings).ContainsKey(name);

	return settings.GetType().GetProperty(name) != null;
}

private static bool RedirectionUrlValidationCallback(string redirectionUrl)
{
	// The default for the validation callback is to reject the URL.
	bool result = false;
	Uri redirectionUri = new Uri(redirectionUrl);
	// Validate the contents of the redirection URL. In this simple validation
	// callback, the redirection URL is considered valid if it is using HTTPS
	// to encrypt the authentication credentials. 
	if (redirectionUri.Scheme == "https")
	{
		result = true;
	}
	return result;
}