(DataFlex) Google Drive Refresh Access Token

Demonstrates how to automatically refresh the access token when it expires.

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

Use ChilkatAx-9.5.0-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoJson
    String sTokenFilePath
    Variant vOauth2
    Handle hoOauth2
    Handle hoRest
    Boolean iBAutoReconnect
    String sJsonResponse
    Handle hoFac
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

    Move True To iSuccess

    // It 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 
    // Google Drive scope.

    // The access token (and refresh token) was previously saved to a JSON file with this format:
    // See Get Google Drive OAuth2 Access Token

    // {
    //   "access_token": "ya29.Gls-BsdxTWuenChv ... yzVIrXikkLxu5T6dy4I6GjADFardoz4Lruw",
    //   "expires_in": 3600,
    //   "refresh_token": "1/tMBJ ... 27D-Hk6rpQYBA",
    //   "scope": "https://www.googleapis.com/auth/drive",
    //   "token_type": "Bearer"
    // }

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Move "qa_data/tokens/googleDrive.json" To sTokenFilePath
    Get ComLoadFile Of hoJson sTokenFilePath To iSuccess

    Get Create (RefClass(cComChilkatOAuth2)) To hoOauth2
    If (Not(IsComObjectCreated(hoOauth2))) Begin
        Send CreateComObject of hoOauth2
    End
    Get ComStringOf Of hoJson "access_token" To sTemp1
    Set ComAccessToken Of hoOauth2 To sTemp1
    Get ComStringOf Of hoJson "refresh_token" To sTemp1
    Set ComRefreshToken Of hoOauth2 To sTemp1

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End

    // Connect using TLS.
    Move True To iBAutoReconnect
    Get ComConnect Of hoRest "www.googleapis.com" 443 True iBAutoReconnect To iSuccess

    // Provide the authentication credentials (i.e. the access token)
    Get pvComObject of hoOauth2 to vOauth2
    Get ComSetAuthOAuth2 Of hoRest vOauth2 To iSuccess

    // We'll test with a simple request to empty trash.
    // If our access token expired, we'll get a 401 response..
    Get ComFullRequestNoBody Of hoRest "DELETE" "/drive/v3/files/trash" To sJsonResponse
    Get ComLastMethodSuccess Of hoRest To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // If the access token expired, we'll get a 401 response status with this response body:
    // {
    //  "error": {
    //   "errors": [
    //    {
    //     "domain": "global",
    //     "reason": "authError",
    //     "message": "Invalid Credentials",
    //     "locationType": "header",
    //     "location": "Authorization"
    //    }
    //   ],
    //   "code": 401,
    //   "message": "Invalid Credentials"
    //  }
    // }
    Get ComResponseStatusCode Of hoRest To iTemp1
    If (iTemp1 = 401) Begin

        Showln "Refreshing access token..."

        Set ComAuthorizationEndpoint Of hoOauth2 To "https://accounts.google.com/o/oauth2/v2/auth"
        Set ComTokenEndpoint Of hoOauth2 To "https://www.googleapis.com/oauth2/v4/token"

        //  Replace these with actual values.
        Set ComClientId Of hoOauth2 To "GOOGLE-CLIENT-ID"
        Set ComClientSecret Of hoOauth2 To "GOOGLE-CLIENT-SECRET"
        Set ComScope Of hoOauth2 To "https://www.googleapis.com/auth/drive"

        // Use OAuth2 to refresh the access token.
        Get ComRefreshAccessToken Of hoOauth2 To iSuccess
        If (iSuccess <> True) Begin
            Get ComLastErrorText Of hoOauth2 To sTemp1
            Showln sTemp1
            Procedure_Return
        End

        // Save the new access token to our XML file (so we can refresh it again when needed).
        Get ComAccessToken Of hoOauth2 To sTemp1
        Get ComUpdateString Of hoJson "access_token" sTemp1 To iSuccess

        Get Create (RefClass(cComCkFileAccess)) To hoFac
        If (Not(IsComObjectCreated(hoFac))) Begin
            Send CreateComObject of hoFac
        End
        Get ComEmit Of hoJson To sTemp1
        Get ComWriteEntireTextFile Of hoFac sTokenFilePath sTemp1 "utf-8" False To iSuccess

        Showln "Access Token Refreshed!"

        // Retry the request with the new access token..
        Get ComFullRequestNoBody Of hoRest "DELETE" "/drive/v3/files/trash" To sJsonResponse
        Get ComLastMethodSuccess Of hoRest To bTemp1
        If (bTemp1 <> True) Begin
            Get ComLastErrorText Of hoRest To sTemp1
            Showln sTemp1
            Procedure_Return
        End

    End

    // A successful response will have a status code equal to 204 and the response body is empty.
    // (If not successful, then there should be a JSON response body with information..)
    Get ComResponseStatusCode Of hoRest To iTemp1
    If (iTemp1 <> 204) Begin
        Get ComResponseStatusCode Of hoRest To iTemp1
        Showln "response status code = " iTemp1
        Get ComResponseStatusText Of hoRest To sTemp1
        Showln "response status text = " sTemp1
        Get ComResponseHeader Of hoRest To sTemp1
        Showln "response header: " sTemp1
        Showln "response JSON: " sJsonResponse
        Procedure_Return
    End

    Showln "Trash Emptied!"


End_Procedure