(VB.NET UWP/WinRT) Office365 Refresh OAuth2 Access Token for SMTP, IMAP, POP

Demonstrates how to refresh an Office365 OAuth2 access token for use in the SMTP, IMAP, and POP3 protocols.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.


' It is assumed we previously obtained an OAuth2 access token.
' This example loads the JSON access token file 
' saved by this example: Get Office365 SMTP/IMAP/POP3 OAuth2 Access Token

Dim jsonToken As New Chilkat.JsonObject
Dim success As Boolean = jsonToken.LoadFile("qa_data/tokens/office365.json")
If (success <> True) Then
    Debug.WriteLine("Failed to load office365.json")
    Exit Sub
End If


' The access token JSON looks like this:

' {
'   "token_type": "Bearer",
'   "scope": "IMAP.AccessAsUser.All openid POP.AccessAsUser.All profile SMTP.Send email",
'   "expires_in": 3599,
'   "ext_expires_in": 3599,
'   "access_token": "...",
'   "refresh_token": "...",
'   "id_token": "...",
'   "expires_on": "1592748507"
' }

Dim oauth2 As New Chilkat.OAuth2

' Update to use your token endpoint.
' In the Azure Portal, in "App registrations", go to "Endpoints" (located to the right of the "+ New registration" link.)
'    Find your endpoint for the "OAuth 2.0 token endpoint (v2)"
'    See Office365 OAuth2 Endpoints

oauth2.TokenEndpoint = "https://login.microsoftonline.com/xxxxxxxxxx-71bf-4ebe-a866-738364321bf2/oauth2/v2.0/token"

' Replace these with actual values.
oauth2.ClientId = "CLIENT_ID"
oauth2.ClientSecret = "CLIENT_SECRET"

' Get the "refresh_token"
oauth2.RefreshToken = jsonToken.StringOf("refresh_token")

' Send the HTTP POST to refresh the access token..
success = Await oauth2.RefreshAccessTokenAsync()
If (success <> True) Then
    Debug.WriteLine(oauth2.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("New access token: " & oauth2.AccessToken)
Debug.WriteLine("New refresh token: " & oauth2.RefreshToken)

' Update the JSON with the new tokens.
jsonToken.UpdateString("access_token",oauth2.AccessToken)
jsonToken.UpdateString("refresh_token",oauth2.RefreshToken)

' Save the new JSON access token response to a file.
Dim sbJson As New Chilkat.StringBuilder
jsonToken.EmitCompact = False
jsonToken.EmitSb(sbJson)
sbJson.WriteFile("qa_data/tokens/office365.json","utf-8",False)

Debug.WriteLine("OAuth2 authorization granted!")
Debug.WriteLine("New Access Token = " & oauth2.AccessToken)