(Visual FoxPro) MercadoLibre Refresh OAuth2 Access Token

Demonstrates how to refresh a MercadoLibre OAuth2 access token. The refresh does not require user interaction via a web browser. If an access token expires (typically with a 401 response code), a new access token can be automatically obtained by using the code in this example.

For more information, see https://developers.mercadolibre.com.ar/es_ar/autenticacion-y-autorizacion#Refresh-token

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

LOCAL loJsonToken
LOCAL lnSuccess
LOCAL loOauth2
LOCAL loSbJson

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

* It is assumed we previously obtained an OAuth2 access token.
* This example loads the JSON access token file 
* saved by this example: Get MercadoLibre OAuth2 Access Token

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJsonToken = CreateObject('Chilkat.JsonObject')
lnSuccess = loJsonToken.LoadFile("qa_data/tokens/mercadolibre.json")
IF (lnSuccess <> 1) THEN
    ? "Failed to load mercadolibre.json"
    RELEASE loJsonToken
    CANCEL
ENDIF

* The access token JSON looks like this:

* {
*   "access_token": "APP_USR-8133606632685744-060115-93e1fd8b5e767c51c238df347bd0b288-577628017",
*   "token_type": "bearer",
*   "expires_in": 21600,
*   "scope": "offline_access read write",
*   "user_id": 577625107,
*   "refresh_token": "TG-5ad522a286f1200006ac4ed1-577625007"
* }

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

loOauth2.TokenEndpoint = "https://api.mercadolibre.com/oauth/token"

* Replace these with actual values.
loOauth2.ClientId = "MY_MERCADOLIBRE_APP_ID"
loOauth2.ClientSecret = "MY_MERCADOLIBRE_APP_SECRET"

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

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

? "New access token: " + loOauth2.AccessToken
? "New refresh token: " + loOauth2.RefreshToken

* Update the JSON with the new tokens.
loJsonToken.UpdateString("access_token",loOauth2.AccessToken)
loJsonToken.UpdateString("refresh_token",loOauth2.RefreshToken)

* Save the new JSON access token response to a file.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbJson = CreateObject('Chilkat.StringBuilder')
loJsonToken.EmitCompact = 0
loJsonToken.EmitSb(loSbJson)
loSbJson.WriteFile("qa_data/tokens/mercadolibre.json","utf-8",0)

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

RELEASE loJsonToken
RELEASE loOauth2
RELEASE loSbJson