(VB.NET) Refresh eBay Application Access Token

This example shows how to get a new eBay REST API access token when the original is close to expiration.

Note: This example requires Chilkat v9.5.0.80 or greater. (This example was written on 21-August-2019, before v9.5.0.80 was released. If Contact Chilkat for a pre-release if the current Chilkat version is not yet at 9.5.0.80 or greater.)

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

' The previously fetched eBay access token looks like this:

' {
'   "access_token": "v^1.1#i^1# ... HwSAAA=",
'   "expires_in": 7200,
'   "refresh_token": "v^1.1#i^1# ... FXjEyODQ=",
'   "refresh_token_expires_in": 47304000,
'   "token_type": "User Access Token"
' }

Dim json As New Chilkat.JsonObject
Dim success As Boolean = json.LoadFile("qa_data/tokens/ebay-access-token.json")
If (success = False) Then
    Debug.WriteLine("Failed to load the existing ebay access token JSON.")
    Exit Sub
End If


Dim oauth2 As New Chilkat.OAuth2

oauth2.TokenEndpoint = "https://api.sandbox.ebay.com/identity/v1/oauth2/token"

' Replace these with actual values.
oauth2.ClientId = "EBAY_CLIENT_ID"
oauth2.ClientSecret = "EBAY_CLIENT_SECRET"

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

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


' Load the access token response into the JSON object 
json.Load(oauth2.AccessTokenResponse)


' Save the new JSON access token response to a file.
' The access + refresh tokens contained in this JSON will be needed for the next refresh.
json.EmitCompact = False
json.WriteFile("qa_data/tokens/ebay-access-token.json")

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