(Delphi DLL) citi Developer OAuth2 Client Credentials Grant

Get access token for your application credentials. You can use this for citi APIs which do not require customer credential verification and consent (e.g. Onboarding).

Note: This example requires Chilkat v11.0.0 or greater.

For more information, see https://sandbox.developerhub.citi.com/api/united-states/retail-bank/identity-security/authorize/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, HttpResponse, StringBuilder, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
http: HCkHttp;
req: HCkHttpRequest;
resp: HCkHttpResponse;
sbResponseBody: HCkStringBuilder;
jResp: HCkJsonObject;
respStatusCode: Integer;
token_type: PWideChar;
access_token: PWideChar;
expires_in: Integer;
consented_on: Integer;
scope: 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 --request POST \
//   --url https://sandbox.apihub.citi.com/gcb/api/clientCredentials/oauth2/token/us/gcb \
//   --header 'accept: application/json' \
//   --user client-id:client-secret \
//   --header 'content-type: application/x-www-form-urlencoded' \
//   --data 'grant_type=client_credentials&scope=%2Fapi'

CkHttp_putLogin(http,'client-id');
CkHttp_putPassword(http,'client-secret');

req := CkHttpRequest_Create();
CkHttpRequest_putHttpVerb(req,'POST');
CkHttpRequest_putPath(req,'/gcb/api/clientCredentials/oauth2/token/us/gcb');
CkHttpRequest_putContentType(req,'application/x-www-form-urlencoded');
CkHttpRequest_AddParam(req,'grant_type','client_credentials');
CkHttpRequest_AddParam(req,'scope','/api');
CkHttpRequest_AddHeader(req,'accept','application/json');

resp := CkHttpResponse_Create();
success := CkHttp_HttpReq(http,'https://sandbox.apihub.citi.com/gcb/api/clientCredentials/oauth2/token/us/gcb',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;

success := CkJsonObject_WriteFile(jResp,'qa_data/tokens/citi_client_credentials.json');
if (success = False) then
  begin
    Memo1.Lines.Add('Failed to save JSON access token file.');
    Exit;
  end;

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

//  {
//    "token_type": "bearer",
//    "access_token": "AAIkMjdh ... 3fsWb7zJ0s",
//    "expires_in": 1800,
//    "consented_on": 1584817860,
//    "scope": "/api"
//  }

//  Sample code for parsing the JSON response...
//  Use the following online tool to generate parsing code from sample JSON:
//  Generate Parsing Code from JSON

token_type := CkJsonObject__stringOf(jResp,'token_type');
access_token := CkJsonObject__stringOf(jResp,'access_token');
expires_in := CkJsonObject_IntOf(jResp,'expires_in');
consented_on := CkJsonObject_IntOf(jResp,'consented_on');
scope := CkJsonObject__stringOf(jResp,'scope');

CkHttp_Dispose(http);
CkHttpRequest_Dispose(req);
CkHttpResponse_Dispose(resp);
CkStringBuilder_Dispose(sbResponseBody);
CkJsonObject_Dispose(jResp);

end;