(Delphi DLL) HMRC Validate Fraud Prevention Headers

Demonstrates how to test (validate) HMRC fraud prevention headers.

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, StringBuilder, Rest, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
success: Boolean;
json: HCkJsonObject;
accessToken: PWideChar;
sbAuthHeaderValue: HCkStringBuilder;
responseStr: PWideChar;

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

rest := CkRest_Create();

success := CkRest_Connect(rest,'test-api.service.hmrc.gov.uk',443,True,True);
if (success = False) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Load the previously fetched access token.
json := CkJsonObject_Create();
success := CkJsonObject_LoadFile(json,'qa_data/tokens/hmrc.json');
accessToken := CkJsonObject__stringOf(json,'access_token');
Memo1.Lines.Add('Using access toke: ' + accessToken);

sbAuthHeaderValue := CkStringBuilder_Create();
CkStringBuilder_Append(sbAuthHeaderValue,'Bearer ');
CkStringBuilder_Append(sbAuthHeaderValue,accessToken);

CkRest_AddHeader(rest,'Accept','application/vnd.hmrc.1.0+json');
CkRest_AddHeader(rest,'Authorization',CkStringBuilder__getAsString(sbAuthHeaderValue));

// Add the fraud prevention headers.
// See https://developer.service.hmrc.gov.uk/api-documentation/docs/fraud-prevention
CkRest_AddHeader(rest,'gov-client-connection-method','DESKTOP_APP_DIRECT');

// This should be generated by an application and persistently stored on the device. The identifier should not expire.
CkRest_AddHeader(rest,'gov-client-device-id','beec798b-b366-47fa-b1f8-92cede14a1ce');

// See https://developer.service.hmrc.gov.uk/api-documentation/docs/fraud-prevention
CkRest_AddHeader(rest,'gov-client-user-ids','os=user123');

// Your local IP addresses (comma separated), such as addresses beginning with "192.168." or "172.16."
CkRest_AddHeader(rest,'gov-client-local-ips','172.16.16.23');
// You'll need to find a way to get your MAC address.  Chilkat does not yet provide this ability...
CkRest_AddHeader(rest,'gov-client-mac-addresses','7C%3AD3%3A0A%3A25%3ADA%3A1C');

CkRest_AddHeader(rest,'gov-client-timezone','UTC+00:00');

// You can probably just hard-code these so they're always the same with each request.
CkRest_AddHeader(rest,'gov-client-window-size','width=1256&height=800');
CkRest_AddHeader(rest,'gov-client-screens','width=1920&height=1080&scaling-factor=1&colour-depth=16');
CkRest_AddHeader(rest,'gov-client-user-agent','Windows/Server%202012 (Dell%20Inc./OptiPlex%20980)');
CkRest_AddHeader(rest,'gov-vendor-version','My%20Desktop%20Software=1.2.3.build4286');

responseStr := CkRest__fullRequestNoBody(rest,'GET','/test/fraud-prevention-headers/validate');
if (CkRest_getLastMethodSuccess(rest) = False) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// If the status code is 200, then the fraud prevention headers were validated.
// The JSON response may include some warnings..
Memo1.Lines.Add('Response status code = ' + IntToStr(CkRest_getResponseStatusCode(rest)));
Memo1.Lines.Add('Response JSON body: ');
Memo1.Lines.Add(responseStr);

CkRest_Dispose(rest);
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sbAuthHeaderValue);

end;