Delphi ActiveX Requires Chilkat v11.0.0+

Bidirectional Sockets (TLS or non-TLS, simultaneous reading and writing a connection)

See more Socket/SSL/TLS Examples

This example demonstrates how to simultaneously read/write on a single socket connection. Delphi ActiveX

var
success: Integer;
tlsRead: TChilkatSocket;
bUseTls: Integer;
maxWaitMs: Integer;
tlsWrite: TChilkatSocket;
task: IChilkatTask;
httpGetReq: WideString;

begin
success := 0;

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

tlsRead := TChilkatSocket.Create(Self);

//  We'll just use an HTTPS server for this example...
bUseTls := 1;
maxWaitMs := 5000;
success := tlsRead.Connect('www.chilkatsoft.com',443,bUseTls,maxWaitMs);
if (success = 0) then
  begin
    Memo1.Lines.Add(tlsRead.LastErrorText);
    Exit;
  end;

//  Chilkat classes are thread-safe.  This means that only one method call can be active
//  at a time for a given object instance.  It would seem that this would prevent the possibility
//  to simultaneously read/write a given connection because it would require two method calls
//  to be simultaneously active: one for reading and one for writing.
//  
//  There's a trick to doing it...
//  
//  The DupSocket method is provided to get a new object instance that shares the same socket
//  connection.  This allows for the coarse-grained object-level thread safety to be maintained, 
//  while finer-grained thread-safety mechanisms keep things kosher internally.

//  One object will be used for reading, and the cloned socket is used for writing.
//  It doesn't matter which --  you can use the cloned socket for reading or the original for writing.
//  However.. if you try to read simultneously from both the original and cloned objects at the same
//  time, then one will block until the other finishes.  (This is because of the finer-grained thread
//  safety internally.)  The same is true if you try to write both socket objects simultaneously.

tlsWrite := TChilkatSocket.Create(Self);
success := tlsRead.DupSocket(tlsWrite.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(tlsRead.LastErrorText);
    Exit;
  end;

//  Let's start an async read on the socket.  Nothing will be arriving until we actually send the GET
//  request and the server responds.  This will read until the end of the HTTP response header.
task := tlsRead.ReceiveUntilMatchAsync(#13#10 + #13#10);
task.Run();

//  Now send the request.  This should not block because the read is happening on the tlsRead object.
httpGetReq := 'GET / HTTP/1.1' + #13#10 + 'Host: www.chilkatsoft.com' + #13#10 + #13#10;
success := tlsWrite.SendString(httpGetReq);
//  Assuming success for the example...

//  Wait for the read task to finish.
//  The 1/0 returned by Wait applies to the Wait method call, not the task.
maxWaitMs := 5000;
success := task.Wait(maxWaitMs);
if (not success or (task.StatusInt <> 7) or (task.TaskSuccess <> 1)) then
  begin
    if (not success) then
      begin
        //  The task.LastErrorText applies to the Wait method call.
        Memo1.Lines.Add(task.LastErrorText);
      end
    else
      begin
        //  The ResultErrorText applies to the underlying task method call (i.e. the Connect)
        Memo1.Lines.Add(task.Status);
        Memo1.Lines.Add(task.ResultErrorText);
      end;

    Exit;
  end;

//  Examine the received HTTP response header:
Memo1.Lines.Add('HTTP response header:');
Memo1.Lines.Add(task.GetResultString());

//  We should get a response that looks like this:
//  	HTTP response header:
//  	HTTP/1.1 200 OK
//  	Cache-Control: private
//  	Content-Length: 7477
//  	Content-Type: text/html
//  	Server: Microsoft-IIS/8.5
//  	Set-Cookie: ASPSESSIONIDSWDSTRTQ=BBNMIKGCHFJNILFFPLDIOGDE; secure; path=/
//  	X-Powered-By: ASP.NET
//  	X-Powered-By-Plesk: PleskWin
//  	Date: Thu, 06 Apr 2017 12:03:30 GMT

//  Forget about the remainder of the HTTP response... The example was only to demonstrate
//  simultaneous reading/writing..
maxWaitMs := 20;
tlsRead.Close(maxWaitMs);