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TIdHttpServer freezing when Active set to False after Windows Update

We have a Indy (version 10.6.1.5235) TIdHttpServer "service" that has worked well for years with Delphi 2007. After the most recent Windows Update (KB4338815 and KB4338830) we noticed the service freezes when TIdHttpServer is set to false.

I have included source code where TIdHttpServer is created. In our service "Stop" handler we set IdHttpServer1.Active to False and this is where it freezes. It seems Indy hangs when it is trying to close the http connections. Is there a work around?

Update One Per Remy Lebeau, I have created a Minimal, Complete, and Verifiable example. Here it is:

procedure TMainForm.Button1Click(Sender: TObject);
begin
  memo1.clear;
  iCall := 0;
  IdHTTPServer1 := TIdHTTPServer.Create;
  IdHTTPServer1.MaxConnections := 10;
  IdHTTPServer1.AutoStartSession := True;
  IdHTTPServer1.SessionState := True;
  IdHTTPServer1.OnCommandGet := IdHTTPServer1CommandGet;
  IdHTTPServer1.KeepAlive := False;
  idHttpServer1.DefaultPort := 80;
  if ReuseSocket.checked then
    IDHTTPSERVER1.ReuseSocket :=  rsTrue;
  IdHTTPServer1.Active := True;
end;


procedure TMainForm.IdHTTPServer1CommandGet(AContext: TIdContext;
  ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);
begin
  iCall := iCall + 1;
  if iCall mod 100 = 0 then
    memo1.lines.add(inttostr(iCall)+ ' calls made');
  AResponseInfo.ContentText := '<html><body>Hello There</body></html';
end;

procedure TMainForm.StopClick(Sender: TObject);
begin
  try
    IdHTTPServer1.Active := False;
    memo1.lines.add('IdHTTPServer1.Active := False;');
  except
    on e: exception do
      memo1.lines.add('Exception on IdHTTPServer1.Active := False; Message:'+e.message);
  end;

end;

Application will run fine but once you click the "Stop" button which sets the IdHttpServer Active property to False it hangs.

Solution

  • You might have encountered this similar issue:

    Windows 2012 R2 closesocket() hangs on listening socket

    The issue was brought by patch from Microsoft KB4338815, which caused closesocket tо hang forever on Intel Xeon processors

    That issue was fixed by uninstalling KB4338815, which you do have installed. So try uninstalling that KB on your system and see if it solves your issue.