(Delphi DLL) Dropbox Refresh OAuth2 Access Token

See more Dropbox Examples

Demonstrates how to mint a new access token using the refresh token obtained when originally getting the OAuth2 access token.

For more information, see https://www.dropbox.com/developers/documentation/http/documentation

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, Http, HttpRequest, StringBuilder, HttpResponse, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: HCkHttp;
success: Boolean;
json: HCkJsonObject;
req: HCkHttpRequest;
resp: HCkHttpResponse;
sbResponseBody: HCkStringBuilder;
jResp: HCkJsonObject;
respStatusCode: Integer;
access_token: PWideChar;

begin
// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

http := CkHttp_Create();

// Implements the following CURL command:

// curl -X GET https://api.dropbox.com/oauth2/token \
//     -d grant_type=refresh_token \
//     -d refresh_token=<YOUR_REFRESH_TOKEN> \
//     -u <YOUR_APP_KEY>:<YOUR_APP_SECRET>

// Use the following online tool to generate HTTP code from a CURL command
// Convert a cURL Command to HTTP Source Code

CkHttp_putLogin(http,'DROPBOX_APP_KEY');
CkHttp_putPassword(http,'DROPBOX_APP_SECRET');

// Get the refresh token from the JSON we saved when originally getting the access token.
// (See Get Dropbox OAuth2 Access Token w/ Refresh Token
json := CkJsonObject_Create();
success := CkJsonObject_LoadFile(json,'qa_data/tokens/dropbox.json');
if (success = False) then
  begin
    Memo1.Lines.Add(CkJsonObject__lastErrorText(json));
    Exit;
  end;

req := CkHttpRequest_Create();
CkHttpRequest_AddParam(req,'grant_type','refresh_token');
CkHttpRequest_AddParam(req,'refresh_token',CkJsonObject__stringOf(json,'refresh_token'));

resp := CkHttp_PostUrlEncoded(http,'https://api.dropbox.com/oauth2/token',req);
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

sbResponseBody := CkStringBuilder_Create();
CkHttpResponse_GetBodySb(resp,sbResponseBody);

jResp := CkJsonObject_Create();
CkJsonObject_LoadSb(jResp,sbResponseBody);
CkJsonObject_putEmitCompact(jResp,False);

Memo1.Lines.Add('Response Body:');
Memo1.Lines.Add(CkJsonObject__emit(jResp));

respStatusCode := CkHttpResponse_getStatusCode(resp);
Memo1.Lines.Add('Response Status Code = ' + IntToStr(respStatusCode));
if (respStatusCode >= 400) then
  begin
    Memo1.Lines.Add('Response Header:');
    Memo1.Lines.Add(CkHttpResponse__header(resp));
    Memo1.Lines.Add('Failed.');
    CkHttpResponse_Dispose(resp);
    Exit;
  end;
CkHttpResponse_Dispose(resp);

// Sample JSON response:
// (Sample code for parsing the JSON response is shown below)

// {
//   "access_token": "sl.AC75WPYRqOi0mxcRqlimbV9FKHu04biz5qHwatG3MTgzFK7kLrGVlM9EgP4603tE7bWw0s1rMbTKiHsf37TUshPYvq-3r0qeBr_PrZIAibN8XOQicvboiOnqx6JrDekq-w8D-tE",
//   "token_type": "bearer",
//   "expires_in": 14400
// }

access_token := CkJsonObject__stringOf(jResp,'access_token');
Memo1.Lines.Add('New Access Token: ' + access_token);

// Perhaps update our Dropbox JSON file with the new access token.
// (The existing refresh token does not change, and can be used over and over to mint new access tokens.)
CkJsonObject_UpdateString(json,'access_token',access_token);

CkJsonObject_WriteFile(json,'qa_data/tokens/dropbox.json');

CkHttp_Dispose(http);
CkJsonObject_Dispose(json);
CkHttpRequest_Dispose(req);
CkStringBuilder_Dispose(sbResponseBody);
CkJsonObject_Dispose(jResp);

end;