(Delphi DLL) 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 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, Http, HttpRequest, HttpResponse, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: HCkHttp;
req: HCkHttpRequest;
json: HCkJsonObject;
success: Boolean;
resp: HCkHttpResponse;

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

http := CkHttp_Create();

req := CkHttpRequest_Create();

// Load a JSON file containing strings with Polish chars.
json := CkJsonObject_Create();
success := CkJsonObject_LoadFile(json,'qa_data/json/has_polish_chars.json');
if (success = False) then
  begin
    Memo1.Lines.Add(CkJsonObject__lastErrorText(json));
    Exit;
  end;

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

// Indicate we wish to explicitly send the charset attribute in the HTTP request header.
CkHttpRequest_putSendCharset(req,True);

// 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 := CkHttp_PostUrlEncoded(http,'https://www.chilkatsoft.com/echoPost.cshtml',req);
if (CkHttp_getLastMethodSuccess(http) <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

Memo1.Lines.Add(CkHttp__lastHeader(http));
Memo1.Lines.Add(CkHttpResponse__bodyStr(resp));

// 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.

CkHttpResponse_Dispose(resp);

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

CkHttpRequest_putSendCharset(req,True);
CkHttpRequest_putCharset(req,'windows-1250');

resp := CkHttp_PostUrlEncoded(http,'https://www.chilkatsoft.com/echoPost.cshtml',req);
if (CkHttp_getLastMethodSuccess(http) <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

Memo1.Lines.Add(CkHttp__lastHeader(http));
Memo1.Lines.Add(CkHttpResponse__bodyStr(resp));

// 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>
// --------------------------------------------------

CkHttpResponse_Dispose(resp);

CkHttp_Dispose(http);
CkHttpRequest_Dispose(req);
CkJsonObject_Dispose(json);

end;