Delphi 2010 - Wininet running out of handles

I have an app that makes intensively uses of Wininet functions to get some data from internet. I am getting a very odd handle related error messages sometimes:

Internal error in ConnectToHost when trying to create a session 
ERROR_INTERNET_OUT_OF_HANDLES: No more handles could be generated at this time. Wininet error code = 12001;

When this occured i noticed that my application had more than 500开发者_JS百科0 handles created. I ran a resource profile and I found out that some handles created by wininet were not being freed.

So, I created a small application to reproduce the issue. The code is simple and does nothing but allocate some wininet handles and then free them. That is the code:

procedure request(const AUrl : AnsiString);
var
  sMethod     : AnsiString;
  pSession    : HINTERNET;
  pConnection : HINTERNET;
  pRequest    : HINTERNET;
  port        : Integer;
  flags       : DWord;
begin
  pSession := InternetOpen(nil, INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);
  if Assigned(pSession) then
  try
    Port := INTERNET_DEFAULT_HTTP_PORT;
    pConnection := InternetConnectA(pSession, PAnsiChar(AUrl), port, nil, nil, INTERNET_SERVICE_HTTP, 0, 0);
    if Assigned(pConnection) then
      try
        sMethod := 'GET';
        flags := INTERNET_SERVICE_HTTP;
        pRequest := HTTPOpenRequestA(pConnection, PAnsiChar(sMethod), PAnsiChar(AUrl), nil, nil, nil, flags, 0);
        try
          if Assigned(pRequest) then
            ShowMessage('ok');
        finally
          InternetCloseHandle(pRequest);
        end;
      finally
        InternetCloseHandle(pConnection);
      end;
  finally
    InternetCloseHandle(pSession);
  end;
end;

Running this sample on my profiler, I get the same handle related issues.

I think that InternetCloseHandle is not freeing the handle as it should be because my resource profile tells me that I have 3 live handles when I close the application. Those are the handles that are not being freed:

pRequest
pConnection
pSession

Does anyone know how to get rid of this?

EDIT

The function InternetCloseHandle is working fine, the return value is true.

EDIT

I have searched a lot on the internet, but i was not able to find anybody complaining about that. But it is happening. I would like to know if anybody reproduced the issue or if it is just me.

It turned out to be a AQtime problem. I downloaded another profiler and I also took a look at Task Manager and it seems that the handles are being released. But I still get the no more handles error sometimes and I have no idea why. But I will open another question, since this one was just to see why those handles were not being released.

Thanks for all help I got.

The Http protocol has some limits and the Wininet is using them. Check at WinInet limits connections per server:

WinInet limits connections to a single HTTP 1.0 server to four simultaneous connections. Connections to a single HTTP 1.1 server are limited to two simultaneous connections. The HTTP 1.1 specification (RFC2616) mandates the two-connection limit. The four-connection limit for HTTP 1.0 is a self-imposed restriction that coincides with the standard that is used by a number of popular Web browsers.

Maybe you should wait until connections are closed before attemping a new connection