(Delphi DLL) Debug REST HTTP Request

Demonstrates how to generate the HTTP Request (with all headers intact) without actually sending the request.

Note: This example requires Chilkat v9.5.0.77 or later.

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, BinData, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
success: Boolean;
json: HCkJsonObject;
sbRequestBody: HCkStringBuilder;
sbResponseBody: HCkStringBuilder;
bdRequest: HCkBinData;

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

// This example will connect to the web server, but does not actually send a request.
// When in DebugMode, the request is composed in memory and can be retrieved by calling
// GetLastDebugRequest.

rest := CkRest_Create();

// Connect Code...
// URL: https://test-api.service.hmrc.gov.uk/organisations/vat/MY_HMRC_VRN/returns
bTls := True;
port := 443;
bAutoReconnect := True;
success := CkRest_Connect(rest,'test-api.service.hmrc.gov.uk',port,bTls,bAutoReconnect);
if (success <> True) then
  begin
    Memo1.Lines.Add('ConnectFailReason: ' + IntToStr(CkRest_getConnectFailReason(rest)));
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Build the request body...
json := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'periodKey','A001');
CkJsonObject_UpdateNumber(json,'vatDueSales','105.50');
CkJsonObject_UpdateNumber(json,'vatDueAcquisitions','-100.45');
CkJsonObject_UpdateNumber(json,'totalVatDue','5.05');
CkJsonObject_UpdateNumber(json,'vatReclaimedCurrPeriod','105.15');
CkJsonObject_UpdateNumber(json,'netVatDue','100.10');
CkJsonObject_UpdateInt(json,'totalValueSalesExVAT',300);
CkJsonObject_UpdateInt(json,'totalValuePurchasesExVAT',300);
CkJsonObject_UpdateInt(json,'totalValueGoodsSuppliedExVAT',3000);
CkJsonObject_UpdateInt(json,'totalAcquisitionsExVAT',3000);
CkJsonObject_UpdateBool(json,'finalised',True);

// Add Headers...
CkRest_AddHeader(rest,'Accept','application/vnd.hmrc.1.0+json');
CkRest_AddHeader(rest,'Authorization','Bearer HMRC_ACCESS_TOKEN');
CkRest_AddHeader(rest,'Content-Type','application/json');

sbRequestBody := CkStringBuilder_Create();
CkJsonObject_EmitSb(json,sbRequestBody);

// Set DebugMode so that no request is actually sent.
CkRest_putDebugMode(rest,True);

sbResponseBody := CkStringBuilder_Create();
success := CkRest_FullRequestSb(rest,'POST','/organisations/vat/MY_HMRC_VRN/returns',sbRequestBody,sbResponseBody);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Get the exact contents of what would've been sent.
// This includes the HTTP start line, the HTTP request headers, and the request body.
// Given that it's possible for the request body to contain binary data,
// the GetLastDebugRequest fetches into a BinData object.
// In this case, however, our request body contained JSON, so we can
// examine it as a string..
bdRequest := CkBinData_Create();
success := CkRest_GetLastDebugRequest(rest,bdRequest);

Memo1.Lines.Add('----');
Memo1.Lines.Add(CkBinData__getString(bdRequest,'utf-8'));
Memo1.Lines.Add('----');

// The output for the above case:

// POST /organisations/vat/MY_HMRC_VRN/returns HTTP/1.1
// Accept: application/vnd.hmrc.1.0+json
// Host: test-api.service.hmrc.gov.uk
// Authorization: Bearer HMRC_ACCESS_TOKEN
// Content-Type: application/json
// Content-Length: 281
// 
// {"periodKey":"A001","vatDueSales":105.50, ... ,"finalised":true}
// 
// 

CkRest_Dispose(rest);
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sbRequestBody);
CkStringBuilder_Dispose(sbResponseBody);
CkBinData_Dispose(bdRequest);

end;