(Visual FoxPro) 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.)

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

LOCAL loJson
LOCAL lnSuccess
LOCAL loOauth2

* 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"
* }

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
lnSuccess = loJson.LoadFile("qa_data/tokens/ebay-access-token.json")
IF (lnSuccess = 0) THEN
    ? "Failed to load the existing ebay access token JSON."
    RELEASE loJson
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.OAuth2')
loOauth2 = CreateObject('Chilkat.OAuth2')

loOauth2.TokenEndpoint = "https://api.sandbox.ebay.com/identity/v1/oauth2/token"

* Replace these with actual values.
loOauth2.ClientId = "EBAY_CLIENT_ID"
loOauth2.ClientSecret = "EBAY_CLIENT_SECRET"

* Get the "refresh_token"
loOauth2.RefreshToken = loJson.StringOf("refresh_token")

* Send the HTTP POST to refresh the access token..
lnSuccess = loOauth2.RefreshAccessToken()
IF (lnSuccess <> 1) THEN
    ? loOauth2.LastErrorText
    RELEASE loJson
    RELEASE loOauth2
    CANCEL
ENDIF

* Load the access token response into the JSON object 
loJson.Load(loOauth2.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.
loJson.EmitCompact = 0
loJson.WriteFile("qa_data/tokens/ebay-access-token.json")

? "OAuth2 authorization granted!"
? "New Access Token = " + loOauth2.AccessToken

RELEASE loJson
RELEASE loOauth2