Outlook REST API：尝试使用AZURE AD身份验证调用API

Question

Using the office 365 Outlook REST API (version 2), I have a web application managing outlook subscriptions to specific mail boxes. I've been able to use the examples to obtain a token and call the API using the authorization code flow, successfully.

But now, I want to use a client credential flow and get a token using Azure AD authentication via delegate permissions (I gave the application all possible delegate permissions under office 365 exchange online). Similar to what I've seen here: Get Office 365 API access token without user interaction

I've registered my application and gotten my tenant ID, client ID & secret. I've been able to get a token but when I try to use it, I get 401, unauthorized back.

Here's how I'm getting the token:

AuthenticationContext authContext = new AuthenticationContext($"{authority}{tenantId}");
clientCredential = new ClientCredential(client_Id, secret);
authResult = await authContext.AcquireTokenAsync(resource, clientCredential);
authResult.AccessToken;

And here's how I'm trying to use the API (trying to delete the subscription using REST sharp in this code):

var token = await GetOtherToken(account);
rc = new RestClient("https://outlook.office.com/api/v2.0");                    
rc.AddDefaultHeader("Authorization", $"Bearer {token}");                        
request = new RestRequest($"me/subscriptions('{restSubId}')", Method.DELETE);
request.AddHeader("Content-Length", "0");
request.AddHeader("Content-Type", "multipart/form-data");

Looks like this is not possible. Please, someone, drop some knowledge. Thanks for reading.

Answer 1

When using client credential flow to acquire a token for resource , you are using application identity instead of as a user's identity. So you should assign application permission for your app(not delegate permissions) . In addition , since you are using app identity instead of user's identity , api can't recognize me ( https://outlook.office.com/api/v2.0/me ) . Please click here for how to build service and daemon apps in Office 365 .