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. Delphi 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
success: Boolean;
http: HCkHttp;
json: HCkJsonObject;
req: HCkHttpRequest;
resp: HCkHttpResponse;
sbResponseBody: HCkStringBuilder;
jResp: HCkJsonObject;
respStatusCode: Integer;
access_token: PWideChar;

begin
success := False;

// 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'));

CkHttpRequest_putHttpVerb(req,'POST');
CkHttpRequest_putContentType(req,'application/x-www-form-urlencoded');

resp := CkHttpResponse_Create();
success := CkHttp_HttpReq(http,'https://api.dropbox.com/oauth2/token',req,resp);
if (success = 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.');
    Exit;
  end;

// 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);
CkHttpResponse_Dispose(resp);
CkStringBuilder_Dispose(sbResponseBody);
CkJsonObject_Dispose(jResp);

end;