Pascal (Lazarus/Delphi)

Debug REST HTTP Request

See more REST Examples

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.

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.StringBuilder,
  Chilkat.Rest,
  Chilkat.BinData,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  rest: TRest;
  bTls: Boolean;
  port: Integer;
  bAutoReconnect: Boolean;
  json: TJsonObject;
  sbRequestBody: TStringBuilder;
  sbResponseBody: TStringBuilder;
  bdRequest: TBinData;

begin
  success := False;

  //  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 := TRest.Create;

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

  //  Build the request body...
  json := TJsonObject.Create;
  json.UpdateString('periodKey','A001');
  json.UpdateNumber('vatDueSales','105.50');
  json.UpdateNumber('vatDueAcquisitions','-100.45');
  json.UpdateNumber('totalVatDue','5.05');
  json.UpdateNumber('vatReclaimedCurrPeriod','105.15');
  json.UpdateNumber('netVatDue','100.10');
  json.UpdateInt('totalValueSalesExVAT',300);
  json.UpdateInt('totalValuePurchasesExVAT',300);
  json.UpdateInt('totalValueGoodsSuppliedExVAT',3000);
  json.UpdateInt('totalAcquisitionsExVAT',3000);
  json.UpdateBool('finalised',True);

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

  sbRequestBody := TStringBuilder.Create;
  json.EmitSb(sbRequestBody);

  //  Set DebugMode so that no request is actually sent.
  rest.DebugMode := True;

  sbResponseBody := TStringBuilder.Create;
  success := rest.FullRequestSb('POST','/organisations/vat/MY_HMRC_VRN/returns',sbRequestBody,sbResponseBody);
  if (success <> True) then
    begin
      WriteLn(rest.LastErrorText);
      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 := TBinData.Create;
  success := rest.GetLastDebugRequest(bdRequest);

  WriteLn('----');
  WriteLn(bdRequest.GetString('utf-8'));
  WriteLn('----');

  //  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}
  //  
  //  


  rest.Free;
  json.Free;
  sbRequestBody.Free;
  sbResponseBody.Free;
  bdRequest.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.