Using Office Outlook API with hard-code user name and password - authentication

Question

I'm trying to build a (C#) web app that allows clients to make appointments with me.
I'd like the web app to be able to read and add entries to my outlook calendar.
Many users will use the web app, but the web app will only access one outlook calendar - mine.
All of the examples I have been able to get working have involved the web app user interactively authenticating - but my users will not know my password.
I would like to hard code my username/email address and password in the web app.
When trying to acquire a token I get an error:
Microsoft.IdentityModel.Clients.ActiveDirectory.AdalServiceException:
AADSTS65001: The user or administrator has not consented to use the application.
Send an interactive authorization request for this user and resource.
I am not an administrator of the tenant. Is there any way I can get this to work without administrator involvement?
Would using some kind of certificate rather than a user name and password as user credentials help?
My code (currently in a simple C# console application) is as follows:
UserCredential uc = new UserCredential(MyUsername, MyPassword);
var AuthContext = new AuthenticationContext("https://login.windows.net/Common");
// this doesn't work unless an unexpired token already exists
ar = AuthContext.AcquireToken("https://outlook.office365.com/", MyClientId, uc);
// this does work, but requires the app user to know the password
ar = AuthContext.AcquireToken("https://outlook.office365.com/", MyClientId, new Uri(MyReturnURI));

Answer 1

To enable use the username and password to request the token directly, we need to consent to use the app.
We can use the OAuth 2.0 authorization code grant flow to grant the consent by user. Here is an sample use the ADAL authentication library(3.13.1.846) to acquire the delegate token:
static string authority= "https://login.microsoftonline.com/common";
public static string GetDeligateToken(string resource, string clientId,string redirectURL)
{
AuthenticationContext authContext = new AuthenticationContext(authority);
AuthenticationResult authResult= authContext.AcquireTokenAsync(resource, clientId,new Uri(redirectURL), new PlatformParameters(PromptBehavior.Auto)).Result;
return authResult.AccessToken;
}
After we consent the app, now we can use the code in your post to acquire the token.