Delphi DLL

Duplicate Python websockets

See more WebSocket Examples

Demonstrates how to duplicate the following Python client-side websocket snippet:

async with websockets.connect('ws://192.168.1.35/websocket') as websocket:
await websocket.send("http.controller_login:username=xxx&password=xxxxx")
response = await websocket.recv()

Delphi 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
success: Boolean;
rest: HCkRest;
ws: HCkWebSocket;
responseBody: PWideChar;
statusCode: Integer;
finalFrame: Boolean;
receivedStr: PWideChar;

begin
success := False;

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

// In Python, the following line of code does more than just connect:
// 
//      websockets.connect('ws://192.168.1.35/websocket')
// 
// It is connecting to 192.168.1.35 without using TLS.  If the URI starts with "wss://", then TLS should be used.
// But this URI begins with just "ws:/", so no TLS.

// Also, after connecting, a GET request is sent to the /websocket endpoint.
// In summary, the websockets.connect function is establishing the connection and it sends a GET request.

// First establish the connection.
// No TLS, use the default HTTP port 80.
rest := CkRest_Create();
success := CkRest_Connect(rest,'192.168.1.35',80,False,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);

// Now send the GET request to /websockets.
responseBody := CkRest__fullRequestNoBody(rest,'GET','/websockets');
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.
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.

// The 1st frame sent by the Python snippet is:
// 
//     websocket.send("http.controller_login:username=xxx&password=xxxxx")
// 

// Send the same using Chilkat, and get the response.
finalFrame := True;
success := CkWebSocket_SendFrame(ws,'http.controller_login:username=xxx&password=xxxxx',finalFrame);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkWebSocket__lastErrorText(ws));
    Exit;
  end;

// Read an incoming frame.
success := CkWebSocket_ReadFrame(ws);
if (success <> True) then
  begin
    Memo1.Lines.Add('Failed to receive a frame');
    Memo1.Lines.Add('ReadFrame fail reason = ' + IntToStr(CkWebSocket_getReadFrameFailReason(ws)));
    Memo1.Lines.Add(CkWebSocket__lastErrorText(ws));
    Exit;
  end;

// Show the string that was received.
receivedStr := CkWebSocket__getFrameData(ws);
Memo1.Lines.Add('Received: ' + receivedStr);

// Continue with whatever additional communications are desired...
// ....
// 

CkRest_Dispose(rest);
CkWebSocket_Dispose(ws);

end;