(Delphi DLL) 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 for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, OAuth2, StringBuilder, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
jsonToken: HCkJsonObject;
success: Boolean;
oauth2: HCkOAuth2;
sbJson: HCkStringBuilder;

begin
// 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

jsonToken := CkJsonObject_Create();
success := CkJsonObject_LoadFile(jsonToken,'qa_data/tokens/mercadolibre.json');
if (success <> True) then
  begin
    Memo1.Lines.Add('Failed to load mercadolibre.json');
    Exit;
  end;

// 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"
// }

oauth2 := CkOAuth2_Create();

CkOAuth2_putTokenEndpoint(oauth2,'https://api.mercadolibre.com/oauth/token');

// Replace these with actual values.
CkOAuth2_putClientId(oauth2,'MY_MERCADOLIBRE_APP_ID');
CkOAuth2_putClientSecret(oauth2,'MY_MERCADOLIBRE_APP_SECRET');

// Get the "refresh_token"
CkOAuth2_putRefreshToken(oauth2,CkJsonObject__stringOf(jsonToken,'refresh_token'));

// Send the HTTP POST to refresh the access token..
success := CkOAuth2_RefreshAccessToken(oauth2);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

Memo1.Lines.Add('New access token: ' + CkOAuth2__accessToken(oauth2));
Memo1.Lines.Add('New refresh token: ' + CkOAuth2__refreshToken(oauth2));

// Update the JSON with the new tokens.
CkJsonObject_UpdateString(jsonToken,'access_token',CkOAuth2__accessToken(oauth2));
CkJsonObject_UpdateString(jsonToken,'refresh_token',CkOAuth2__refreshToken(oauth2));

// Save the new JSON access token response to a file.
sbJson := CkStringBuilder_Create();
CkJsonObject_putEmitCompact(jsonToken,False);
CkJsonObject_EmitSb(jsonToken,sbJson);
CkStringBuilder_WriteFile(sbJson,'qa_data/tokens/mercadolibre.json','utf-8',False);

Memo1.Lines.Add('OAuth2 authorization granted!');
Memo1.Lines.Add('New Access Token = ' + CkOAuth2__accessToken(oauth2));

CkJsonObject_Dispose(jsonToken);
CkOAuth2_Dispose(oauth2);
CkStringBuilder_Dispose(sbJson);

end;