TCP Socket Connect through HTTP Proxy

Demonstrates how to connect through an HTTP proxy server.

Download Chilkat Socket ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATSOCKETLib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
socket: TChilkatSocket;
success: Integer;
hostname: String;
ssl: Integer;
maxWaitMillisec: Integer;
receivedMsg: String;

begin
socket := TChilkatSocket.Create(Self);

success := socket.UnlockComponent('Anything for 30-day trial');
if (success <> 1) then
  begin
    ShowMessage('Failed to unlock component');
    Exit;
  end;

//  To connect through an HTTP proxy, set the HttpProxyHostname
//  and HttpProxyPort properties to the hostname (or IP address)
//  and port of the HTTP proxy.  Typical port numbers used by
//  HTTP proxy servers are 3128 and 8080.
socket.HttpProxyHostname := 'www.my-http-proxy.com';
socket.HttpProxyPort := 3128;

//  Important:  Your HTTP proxy server must allow non-HTTP
//  traffic to pass.  Otherwise this does not work.

//  Connect (via the HTTP proxy) to port 5555 of 192.168.1.108.
//  hostname may be a domain name or IP address.
hostname := '192.168.1.108';
ssl := 0;
maxWaitMillisec := 20000;
success := socket.Connect(hostname,5555,ssl,maxWaitMillisec);
if (success <> 1) then
  begin
    ShowMessage(socket.LastErrorText);
    Exit;
  end;

//  Set maximum timeouts for reading an writing (in millisec)
socket.MaxReadIdleMs := 10000;
socket.MaxSendIdleMs := 10000;

//  The ficticious server (in this example) is going to send a "Hello World!"
//  message.  Read it:

receivedMsg := socket.ReceiveString();
if (Length(receivedMsg) = 0 ) then
  begin
    ShowMessage(socket.LastErrorText);
    Exit;
  end;

//  Close the connection with the server
//  Wait a max of 20 seconds (20000 millsec)
socket.Close(20000);

ShowMessage(receivedMsg);
end;