(Delphi ActiveX) DVLA Vehicle Enquiry Service

Demonstrates how to make a call to the DVLA Vehicle Enquiry API to get vehicle details of a specified vehicle. It uses the vehicle registration number as input to search and provide details of the vehicle.

For more information, see https://developer-portal.driver-vehicle-licensing.api.gov.uk/apis/vehicle-enquiry-service/vehicle-enquiry-service-description.html

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: TChilkatHttp;
success: Integer;
json: TChilkatJsonObject;
resp: IChilkatHttpResponse;
sbResponseBody: TChilkatStringBuilder;
jResp: TChilkatJsonObject;
respStatusCode: Integer;
artEndDate: WideString;
co2Emissions: Integer;
colour: WideString;
engineCapacity: Integer;
fuelType: WideString;
make: WideString;
markedForExport: Integer;
monthOfFirstRegistration: WideString;
motStatus: WideString;
registrationNumber: WideString;
revenueWeight: Integer;
taxDueDate: WideString;
taxStatus: WideString;
typeApproval: WideString;
wheelplan: WideString;
yearOfManufacture: Integer;
euroStatus: WideString;
realDrivingEmissions: WideString;
dateOfLastV5CIssued: WideString;

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

http := TChilkatHttp.Create(Self);

// Implements the following CURL command:

// curl -X POST https://driver-vehicle-licensing.api.gov.uk/vehicle-enquiry/v1/vehicles \
//   -H "x-api-key: supplied API key" \
//   -H "Accept: application/json" \
//   -d '{"registrationNumber": "ABC1234"}'

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

// Use this online tool to generate code from sample JSON:
// Generate Code to Create JSON

// The following JSON is sent in the request body.

// {
//   "registrationNumber": "ABC1234"
// }

json := TChilkatJsonObject.Create(Self);
json.UpdateString('registrationNumber','ABC1234');

http.SetRequestHeader('Accept','application/json');
http.SetRequestHeader('x-api-key','supplied API key');

resp := http.PostJson3('https://driver-vehicle-licensing.api.gov.uk/vehicle-enquiry/v1/vehicles','application/json',json.ControlInterface);
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

sbResponseBody := TChilkatStringBuilder.Create(Self);
resp.GetBodySb(sbResponseBody.ControlInterface);
jResp := TChilkatJsonObject.Create(Self);
jResp.LoadSb(sbResponseBody.ControlInterface);
jResp.EmitCompact := 0;

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

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

    Exit;
  end;

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

// {
//   "artEndDate": "2025-02-28",
//   "co2Emissions": 135,
//   "colour": "BLUE",
//   "engineCapacity": 2494,
//   "fuelType": "PETROL",
//   "make": "ROVER",
//   "markedForExport": false,
//   "monthOfFirstRegistration": "2004-12",
//   "motStatus": "No details held by DVLA",
//   "registrationNumber": "ABC1234",
//   "revenueWeight": 1640,
//   "taxDueDate": "2007-01-01",
//   "taxStatus": "Untaxed",
//   "typeApproval": "N1",
//   "wheelplan": "NON STANDARD",
//   "yearOfManufacture": 2004,
//   "euroStatus": "EURO 6 AD",
//   "realDrivingEmissions": "1",
//   "dateOfLastV5CIssued": "2016-12-25"
// }

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

artEndDate := jResp.StringOf('artEndDate');
co2Emissions := jResp.IntOf('co2Emissions');
colour := jResp.StringOf('colour');
engineCapacity := jResp.IntOf('engineCapacity');
fuelType := jResp.StringOf('fuelType');
make := jResp.StringOf('make');
markedForExport := jResp.BoolOf('markedForExport');
monthOfFirstRegistration := jResp.StringOf('monthOfFirstRegistration');
motStatus := jResp.StringOf('motStatus');
registrationNumber := jResp.StringOf('registrationNumber');
revenueWeight := jResp.IntOf('revenueWeight');
taxDueDate := jResp.StringOf('taxDueDate');
taxStatus := jResp.StringOf('taxStatus');
typeApproval := jResp.StringOf('typeApproval');
wheelplan := jResp.StringOf('wheelplan');
yearOfManufacture := jResp.IntOf('yearOfManufacture');
euroStatus := jResp.StringOf('euroStatus');
realDrivingEmissions := jResp.StringOf('realDrivingEmissions');
dateOfLastV5CIssued := jResp.StringOf('dateOfLastV5CIssued');
end;