(VB.NET) GeoOp Exchange Refresh Token for New Access Token

Demonstrates how to use the /oauth2/token endpoint to exchange it for a new access token once the current access token has expired.

Note: This example requires Chilkat v9.5.0.65 or greater.

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

' This example also assumes that OAuth2 access and refresh tokens were previously fetched.
' and saved in a JSON file.  

' First get our previously obtained refresh token.
' { .... "refresh_token":"e6dqdG....mzjpT04w==", .... }
Dim jsonToken As New Chilkat.JsonObject
Dim success As Boolean = jsonToken.LoadFile("qa_data/tokens/geoop.json")

Dim rest As New Chilkat.Rest

' Connect to GeoOp...
Dim bAutoReconnect As Boolean = True
success = rest.Connect("login.geoop.com",443,True,bAutoReconnect)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' Set the X-Version header.
rest.AddHeader("X-Version","1.0")

' Provide the required form params to get the new access token
Debug.WriteLine("refresh_token = " & jsonToken.StringOf("refresh_token"))
rest.AddQueryParam("refresh_token",jsonToken.StringOf("refresh_token"))
rest.AddQueryParam("grant_type","refresh_token")
rest.AddQueryParam("client_id","GEOOP-CLIENT-ID")
rest.AddQueryParam("client_secret","GEOOP-CLIENT-SECRET")

Dim responseBody As String = rest.FullRequestFormUrlEncoded("POST","/oauth2/token")
If (rest.LastMethodSuccess <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' If the response status code did not indicate success, then see what happened..
If (rest.ResponseStatusCode <> 200) Then
    Debug.WriteLine("Request Header: ")
    Debug.WriteLine(rest.LastRequestHeader)
    Debug.WriteLine("----")
    Debug.WriteLine("Response StatusCode = " & rest.ResponseStatusCode)
    Debug.WriteLine("Response StatusLine: " & rest.ResponseStatusText)
    Debug.WriteLine("Response Header:")
    Debug.WriteLine(rest.ResponseHeader)
    Debug.WriteLine(responseBody)
    Exit Sub
End If


Dim json As New Chilkat.JsonObject
json.EmitCompact = False
json.Load(responseBody)

' Show the full JSON response.  It should contain the new access token...
Debug.WriteLine(json.Emit())