(Delphi DLL) WebSocket over TLS

Establishing a WebSocket connection over TLS is exactly the same as for TCP, except for a few arguments passed to the Connect method.

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, WebSocket, Rest;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
bUseTls: Boolean;
success: Boolean;
ws: HCkWebSocket;
responseBody: PWideChar;
statusCode: Integer;

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

//  --------------------------------------------------
//  A WebSocket connection begins life as an HTTP GET request containing a few special header fields,
//  such as "Upgrade: websocket".

//  Your application will use the Chilkat Rest class to send the initial HTTP GET.  This allows you
//  to use the full capability of the Chilkat Rest class to customize the GET for any particular situation.
//  For example:
// 
//    - If custom HTTP request header fields must be added.
//    - If authentication is required, such as OAuth2, OAuth1, Basic HTTP Auth, etc.
//    - If HTTPS, SSH Tunneling, Proxies (HTTP or SOCKS), or other advanced connection or TLS features are required.
// 

rest := CkRest_Create();
//  ------------------------------------------------------------------
//  To use TLS, connect to the TLS port (typically 443) and tell the rest.Connect method
//  that it's a TLS connection.
//  ------------------------------------------------------------------
bUseTls := True;
success := CkRest_Connect(rest,'someserver.com',443,bUseTls,False);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

ws := CkWebSocket_Create();

//  Tell the WebSocket to use this connection.
success := CkWebSocket_UseConnection(ws,rest);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkWebSocket__lastErrorText(ws));
    Exit;
  end;

//  Add the standard WebSocket open handshake headers that will be needed.
//  (This adds the required HTTP request headers to the rest object.)
CkWebSocket_AddClientHeaders(ws);

//  Add any additional headers that might be desired.
//  Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
CkRest_AddHeader(rest,'Sec-WebSocket-Protocol','x-something');
CkRest_AddHeader(rest,'Origin','http://someserver.com');

//  Do the open handshake.
responseBody := CkRest__fullRequestNoBody(rest,'GET','/something');
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

//  If successful, the HTTP response status code should be 101,
//  and the response body will be empty. (If it failed, we'll have a look
//  at the response body..)
statusCode := CkRest_getResponseStatusCode(rest);
Memo1.Lines.Add('Response status code: ' + IntToStr(statusCode));

if (statusCode <> 101) then
  begin
    Memo1.Lines.Add(responseBody);
    Memo1.Lines.Add('-- Failed because of unexpected response status code.');
    Exit;
  end;

//  We have the expected 101 response, so let's now validate the
//  contents of the response, such as the value sent by the server in the
//  Sec-WebSocket-Accept header.
success := CkWebSocket_ValidateServerHandshake(ws);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkWebSocket__lastErrorText(ws));
    Exit;
  end;

Memo1.Lines.Add('WebSocket connection successful.');

//  The application may now begin sending and receiving frames on the WebSocket connection.
//  (At this point, we're done with the rest object...)

CkRest_Dispose(rest);
CkWebSocket_Dispose(ws);

end;