(VBScript) Refresh Access Token on 401 Unauthorized and Retry (Service Account)

See more Google Cloud Storage Examples

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

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

' This example uses a previously obtained access token having permission for the 
' scope "https://www.googleapis.com/auth/cloud-platform"

' In this example, Get Google Cloud Storage OAuth2 Access Token, 
' the service account access token was saved to a text file.  This example fetches the access token from the file..
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.StringBuilder")
set sbToken = CreateObject("Chilkat.StringBuilder")
success = sbToken.LoadFile("qa_data/tokens/googleCloudStorageAccessToken.txt","utf-8")
If (success = 0) Then
    outFile.WriteLine("Failed to load access token.")
    WScript.Quit
End If

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Http")
set http = CreateObject("Chilkat.Http")

http.AuthToken = sbToken.GetAsString()

' Construct a URL to download an object named "starfish.jpg" from the "chilkat-ocean" bucket.
success = http.SetUrlVar("bucket_name","chilkat-ocean")
success = http.SetUrlVar("object_name","starfish.jpg")
url = "https://www.googleapis.com/storage/v1/b/{$bucket_name}/o/{$object_name}?alt=media"

' If there is an error response, then we didn't actually download the file data,
' but instead we downloaded an error response..
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.BinData")
set fileData = CreateObject("Chilkat.BinData")
success = http.DownloadBd(url,fileData)
responseCode = http.LastStatus
If ((success = 0) And (responseCode <> 401)) Then
    outFile.WriteLine(http.LastErrorText)
    WScript.Quit
End If

If (responseCode = 401) Then
    outFile.WriteLine("Received 401 Unauthorized response. Attempting to refresh the access token...")

    ' May be that the access token expired.
    ' Load our JSON key and request a new access token, then retry the original request.
    ' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.FileAccess")
    set fac = CreateObject("Chilkat.FileAccess")
    jsonKey = fac.ReadEntireTextFile("qa_data/googleApi/ChilkatCloud-13a07a2e8b3f.json","utf-8")
    If (fac.LastMethodSuccess <> 1) Then
        outFile.WriteLine(fac.LastErrorText)
        WScript.Quit
    End If

    ' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.AuthGoogle")
    set gAuth = CreateObject("Chilkat.AuthGoogle")
    gAuth.JsonKey = jsonKey
    gAuth.Scope = "https://www.googleapis.com/auth/cloud-platform"
    gAuth.ExpireNumSeconds = 3600
    gAuth.SubEmailAddress = ""

    ' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Socket")
    set tlsSock = CreateObject("Chilkat.Socket")
    success = tlsSock.Connect("www.googleapis.com",443,1,5000)
    If (success <> 1) Then
        outFile.WriteLine(tlsSock.LastErrorText)
        WScript.Quit
    End If

    success = gAuth.ObtainAccessToken(tlsSock)
    If (success <> 1) Then
        outFile.WriteLine(gAuth.LastErrorText)
        WScript.Quit
    End If

    success = fac.WriteEntireTextFile("qa_data/tokens/googleCloudStorageAccessToken.txt",gAuth.AccessToken,"utf-8",0)

    ' Retry the original request.
    http.AuthToken = gAuth.AccessToken
    success = http.DownloadBd(url,fileData)
    If (success = 0) Then
        outFile.WriteLine(http.LastErrorText)
        WScript.Quit
    End If

End If

If (responseCode <> 200) Then
    ' Get the error response
    ' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.StringBuilder")
    set sbErrorResponse = CreateObject("Chilkat.StringBuilder")
    success = sbErrorResponse.AppendBd(fileData,"utf-8",0,0)
    outFile.WriteLine("Error response code = " & responseCode)
    outFile.WriteLine("Error:")
    outFile.WriteLine(sbErrorResponse.GetAsString())
    WScript.Quit
End If

outFile.WriteLine("Success.")

' Save the downloaded data to a file.
success = fileData.WriteFile("qa_output/starfish.jpg")

outFile.Close