Graph SDK OAUTH ADAL client credentials for reuse? later - wpf

Question

So we have an application that allows you to create a xml file that runs the app again at a later stage (which may or may not have a user in attendance). Files are stored on the user cloud drive platform of choice. So the process is
Workflow 1
Authenticate to cloud with User 1 details/input
Select files to Download and use
Save and encrypt file metadata and Refresh token to xml file. (app workflow 1)
Workflow 2 ( can be repeated multiple thousands of times)
Send xml file to another pc with User 2. (either by email or remotely through a console
that pc then runs under user 2
start app
App authenticates automatically using refresh token saved in xml file with no user input (as there is a very high chance of the user who created workflow 1 not being in the same city as where workflow 2 is running
Downloads files
applies files (app workflow 2)
PROBLEM
all other platforms we cater for (Dropbox and google and onedrive) gives us access to the refresh token and allow us to authenticate with it again , however the onedrive for business (graph sdks) give us a Token cache which is session based?
Questions
So I need to know how I can get the refresh token from the Token Cache so we can reuse it at a later stage. (yes I'm aware that it will expire after 6 months which is acceptable) .
When i have the refresh token how do initiate a call to refresh the token
Further note - I have managed to handle all platforms before Within silverlight (where the sdks are not supported) through directly calling the rest api calls but we are converting our solution to WPF and would want to use the sdks
thanks

Answer 1

I assume you were developing Microsoft Graph SDK when you mentioned graph sdks.
AFAIK, this library does not include any default authentication implementations. Instead, the user will want to authenticate with the library of their choice, or against the OAuth endpoint directly, and built-in DelegateAuthenticationProvider class to authenticate each request.
And if you were authenticating Azure AD with Active Directory Authentication Library, you can use the default token cache which use memory to store the cache or you can implement the token cache based on your requirement.
So I need to know how I can get the refresh token from the Token Cache so we can reuse it at a later stage. (yes I'm aware that it will expire after 6 months which is acceptable) .
When you using the ADAL library, there is no need to get the refresh token manually, it will handle for us to renew the access token if the refresh token is existed.
When i have the refresh token how do initiate a call to refresh the token
If you want to perform the request yourself to refresh the access token, you can refer the request below, and more detail you can refer this document.
POST /{tenant}/oauth2/token HTTP/1.1
Host: https://login.microsoftonline.com
Content-Type: application/x-www-form-urlencoded
client_id=6731de76-14a6-49ae-97bc-6eba6914391e
&refresh_token=OAAABAAAAiL9Kn2Z27UubvWFPbm0gLWQJVzCTE9UkP3pSx1aXxUjq...
&grant_type=refresh_token
&resource=https%3A%2F%2Fservice.contoso.com%2F
&client_secret=JqQX2PNo9bpM0uEihUPzyrh // NOTE: Only required for web apps

Answer 2

OK so the answer is taking the tokencache from the PublicIdentityApp and serializing as below.
var tokenCache = _app.UserTokenCache;
var tokenBytes = tokenCache.Serialize();
var tokenString = Convert.ToBase64String(tokenBytes);
And deserializing it later.
_app = new Microsoft.Identity.Client.PublicClientApplication(ClientID);
var array = Convert.FromBase64String(bytestring);
_app.UserTokenCache.Deserialize(array);
authHelper = new AuthenticationHelper(_app);
var authorise = await authHelper.GetTokenForUserAsync()