(Visual Basic 6.0) 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 ChilkatJsonObject
Dim success As Long
success = jsonToken.LoadFile("qa_data/tokens/geoop.json")

Dim rest As New ChilkatRest

' Connect to GeoOp...
Dim bAutoReconnect As Long
bAutoReconnect = 1
success = rest.Connect("login.geoop.com",443,1,bAutoReconnect)
If (success <> 1) Then
    Debug.Print rest.LastErrorText
    Exit Sub
End If

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

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

Dim responseBody As String
responseBody = rest.FullRequestFormUrlEncoded("POST","/oauth2/token")
If (rest.LastMethodSuccess <> 1) Then
    Debug.Print 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.Print "Request Header: "
    Debug.Print rest.LastRequestHeader
    Debug.Print "----"
    Debug.Print "Response StatusCode = " & rest.ResponseStatusCode
    Debug.Print "Response StatusLine: " & rest.ResponseStatusText
    Debug.Print "Response Header:"
    Debug.Print rest.ResponseHeader
    Debug.Print responseBody
    Exit Sub
End If

Dim json As New ChilkatJsonObject
json.EmitCompact = 0
success = json.Load(responseBody)

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