(Delphi ActiveX) Send HTTP POST using non-UTF8 such as Windows-1250

Demonstrates how to specify the character encoding (charset) to be used for the body of an HTTP POST.

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;
req: TChilkatHttpRequest;
json: TChilkatJsonObject;
success: Integer;
resp: IChilkatHttpResponse;

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

http := TChilkatHttp.Create(Self);

req := TChilkatHttpRequest.Create(Self);

// Load a JSON file containing strings with Polish chars.
json := TChilkatJsonObject.Create(Self);
success := json.LoadFile('qa_data/json/has_polish_chars.json');
if (success = 0) then
  begin
    Memo1.Lines.Add(json.LastErrorText);
    Exit;
  end;

// Add the request params expected by the server-side:
req.AddParam('tytul',json.StringOf('tytul'));
req.AddParam('tresc',json.StringOf('tresc'));

// Indicate we wish to explicitly send the charset attribute in the HTTP request header.
req.SendCharset := 1;

// Send the POST
// You can send the POST to the URL below.  It will respond with the request body in quoted-printable format.
// Using quoted-printable, we can easily see the binary bytes for the accented chars.

resp := http.PostUrlEncoded('https://www.chilkatsoft.com/echoPost.cshtml',req.ControlInterface);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(http.LastHeader);
Memo1.Lines.Add(resp.BodyStr);

// Sample output:

// --------------------------------------------------
// POST /echoPost.cshtml HTTP/1.1
// Host: www.chilkatsoft.com
// Content-Type: application/x-www-form-urlencoded; charset=utf-8
// Content-Length: 79
// 
// <pre>tytul=3DPrzyk%C5%82ad&amp;tresc=3DPrzyk%C5%82ad
// %82oszenie</pre>
// --------------------------------------------------

// We can see by the %C5%82 that utf-8 was sent, because %C5%82 is the 2-byte representation of a particular Polish char.

// -----------------------
// However.. we can change the charset used for the HTTP request by specifying the request object's charset.

req.SendCharset := 1;
req.Charset := 'windows-1250';

resp := http.PostUrlEncoded('https://www.chilkatsoft.com/echoPost.cshtml',req.ControlInterface);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(http.LastHeader);
Memo1.Lines.Add(resp.BodyStr);

// Sample output...
// You can see how the bytes used for the Polish chars are now 1-byte per char (i.e. using Windows-1250) 

// --------------------------------------------------
// POST /echoPost.cshtml HTTP/1.1
// Host: www.chilkatsoft.com
// Content-Type: application/x-www-form-urlencoded; charset=windows-1250
// Content-Length: 70
// 
// <pre>tytul=3DPrzyk%B3ad&amp;tresc=3DPrzyk%B3ad
// e</pre>
// --------------------------------------------------
end;