Shows how to perform authentication and retrieval of data from D365 Finance and Operations using OData and the Service to service calls using client credentials

OdataQueryD365FinanceAndOperationsTest.cs

//more details at: https://blog.aggregatedintelligence.com/2020/09/d365-finance-and-operations-odata-query.html

var baseUrl = "https://myDomain.sandbox.operations.dynamics.com"; //a trailing slash here will cause a "No P3P Policy defined" error
var tenantId = "TENANTID AS A GUID HERE";

string applicationId = "APPLICATION GUID HERE";
string clientSecret = "CLIENT SECRET HERE";

string api = "data/";
var authorityUrl = $"https://login.windows.net/{tenantId}";

AuthenticationContext authContext = new AuthenticationContext(authorityUrl);
Task<AuthenticationResult> taskResult = authContext.AcquireTokenAsync(baseUrl, new ClientCredential(applicationId, clientSecret));
AuthenticationResult result = taskResult.Result;

using (var httpClient = new HttpClient())
{
	httpClient.Timeout = new TimeSpan(0, 2, 0);  // 2 minutes
	string authorizationHeader = result.CreateAuthorizationHeader();
	httpClient.DefaultRequestHeaders.Add("Authorization", authorizationHeader);

	HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Get, url);
	req.Method = HttpMethod.Get;

	// Wait for the web service response.
	HttpResponseMessage response;
	Stopwatch stopwatch = Stopwatch.StartNew();
	response = httpClient.SendAsync(req).Result;
	if (response.IsSuccessStatusCode)
	{
		stopwatch.ElapsedMilliseconds.Dump("Result returned (ms)");
		stopwatch.Restart();
		var responseBodyAsText = response.Content.ReadAsStringAsync().Result;
		Console.WriteLine(responseBodyAsText);
	}
	else
	{
		Console.WriteLine(response.StatusCode + Environment.NewLine + response.ReasonPhrase);
	}
}

More details can be found at: https://blog.aggregatedintelligence.com/2020/09/d365-finance-and-operations-odata-query.html