Recipe10.15.Connecting to an Already Running Instance of Internet Explorer

Recipe 10.15. Connecting to an Already Running Instance of Internet Explorer

Credit: Bill Bell, Graham Fawcett

Problem

Instantiating Internet Explorer to access its interfaces via COM is easy, but you want to connect to an already running instance.

Solution

The simplest approach is to rely on Internet Explorer's CLSID:

from win32com.client import Dispatch ShellWindowsCLSID = '{9BA05972-F6A8-11CF-A442-00A0C90A8F39}' ShellWindows = Dispatch(ShellWindowsCLSID) print '%d instances of IE' % len(shellwindows) print for shellwindow in ShellWindows :     print shellwindow     print shellwindos.LocationName     print shellwindos.LocationURL     print

Discussion

Dispatching on the CLSID provides a sequence of all the running instances of the application with that class. Of course, there could be none, one, or more. If you're interested in a specific instance, you may be able to identify it by checking, for example, for its properties LocationName and LocationURL.

You'll see that Windows Explorer and Internet Explorer have the same CLSIDthey're basically the same application. If you need to distinguish between them, you can try adding at the start of your script the statement:

from win32gui import GetClassName

and then checking each shellwindow in the loop with:

    if GetClassName(shellwindow.HWND) == 'IEFrame':         ...

'IEFrame' is supposed to result from this call (according to the docs) for all Internet Explorer instances and those only. However, I have not found this check to be wholly reliable across all versions and patch levels of Windows and Internet Explorer, so, take this approach as just one possibility (which is why I haven't added this check to the recipe's official "Solution").

This recipe does not let you receive IE events. The most important event is probably DocumentComplete. You can roughly substitute checks on the Busy property for the inability to wait for that event, but remember not to poll too frequently (for that or any other property) or you may slow down your PC excessively. Something like:

    while shellwindow.Busy:         time.sleep(0.2)

Sleeping 0.2 seconds between checks may be a reasonable compromise between responding promptly and not loading your PC too heavily with a busy-waiting-loop.

Recipe10.15.Connecting to an Already Running Instance of Internet Explorer