Get Office 365 API access token without user interaction

Question

I want to add a feature to my application so that it will be able to add calendar events to outlook.com without user interaction.

All the examples I've seen require user to login to be able to access office 365 api token. How do i get that token without user interaction?

Answer 1

You can use the Client Credential to request the token instead of OAuth 2.0 Code Grant flow.

Here is the request for your reference:

POST https://login.microsoftonline.com/<tenantId>/oauth2/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded

grant_type=client_credentials
&client_id=<clientId>
&client_secret=<clientSecret>
&resource=https://outlook.office.com

And here is the sample using the Microsoft.IdentityModel.Clients.ActiveDirectory to request hte token:

   public static async Task<string> GetTokenAsync(string resource, string clientId, string secrect)
    {
        string authority = "https://login.microsoftonline.com/{yourTenantName}";
        AuthenticationContext authContext = new AuthenticationContext(authority);

        ClientCredential clientCredential = new ClientCredential(clientId, secrect);
        AuthenticationResult authResult=await authContext.AcquireTokenAsync(resource, clientCredential);
        return authResult.AccessToken;
    }

More detail about Office 365 REST, please refer here.