getting HTML DOM events via win32com

[colin roald]

I am trying to puzzle out the win32com interface, specifically as a 
means to automate Internet Explorer.

I have been able at various points to get win32com.client.Dispatch
and DispatchWithEvents to work as advertised.  My current problem
has to do with connecting to HTML DOM events, ie, through 
HTMLDocumentEvents2.

The following code is derived with some modification from a sample
posted by Alex Martelli in December 2000
(http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=utf-8&threadm=91t2mf02dob%40news2.newsguy.com&rnum=1&prev=/groups%3Fq%3DHTMLDocumentEvents2%2Bpython%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3Dutf-8%26selm%3D91t2mf02dob%2540news2.newsguy.com%26rnum%3D1).
It is supposed to trap onclick events from the document.  (Code follows.)

On Monday it worked.  Today it is not working.  I do not know why.
It doesn't throw any errors -- it just doesn't receive any events.

Questions:

(1.)  Is there any documentation, anywhere, that explains exactly how
      the events describe at 
      http://msdn.microsoft.com/library/default.asp?url=/workshop/browser/mshtml/reference/events/htmldocumentevents2/htmldocumentevents2.asp
      are translated into Python methods?  How do I know what name and
      signature I'm supposed to give my handler method (Ononclick?)?
      What *are* its arguments, anyway?

(2.) Is it possible that I haven't Ensured Module for the right classes?
     How would I be able to tell what's missing?  (No errors are
     thrown.)  I am hopelessly confused trying to sort out the functions
     of all the Modules and CoClasses and Interfaces and TypeLibs.  The
     first four lines of EnsureModuleForTypelibOfObject contains an
     obscure series of multiple indirections I can't quite puzzle out --
     where is this stuff documented?

(3.) gen_py/HTMLDocumentEvents2.py contains an 'onclick' method already,
     but it's body ('return self._oleobj_.InvokeTypes(0xfffffda8, LCID,
     1, (11, 0), ((9, 1),),pEvtObj)') is too obscure for me to decipher.
     what does it do?  Am I *supposed* to override it, or supposed to 
     *not* override it?

Thanks for any help you can give me.  Much appreciated!


# ---- begin code ------------------------------------------------------

# testing trapping HTML DOM events

import sys, win32com.client.gencache, pythoncom, win32com.client
import time
from pywin.tools import browser

seen = 0

def EnsureModuleForTypelibOfObject(obj, bForDemand=1):
    try:
        typeinfo = obj._oleobj_.GetTypeInfo()
        clsid = typeinfo.GetTypeAttr()[0]
        typelib, index = typeinfo.GetContainingTypeLib()
        typelib_attr = typelib.GetLibAttr()
        # EnsureModule(typelibCLSID, lcid, major, minor,
	progressInstance=None, bValidateFile=1, bForDemand=0,
	bBuildHidden=1)
        return win32com.client.gencache.EnsureModule(
            typelib_attr[0], typelib_attr[1], typelib_attr[3],
            typelib_attr[4], bForDemand=bForDemand)
    except pythoncom.com_error:
            raise TypeError, "This COM object can not automate the
	    makepy process - please run makepy manually for this object"

ie =
win32com.client.gencache.EnsureDispatch("InternetExplorer.Application")
ie.Navigate('http://www.google.com/')
ie.Visible=1

while not (hasattr(ie, 'Document')): time.sleep(0.1)
html_module = EnsureModuleForTypelibOfObject(ie.Document)
print 'html_module = ',html_module
HTMLDocumentEvents2Class = win32com.client.gencache.GetClassForCLSID(
    '{3050F613-98B5-11CF-BB82-00AA00BDCE0B}') # HTMLDocumentEvents2

class Handler(HTMLDocumentEvents2Class):
    def __init__(self, obj):
        #self.__dict__['seen'] = 0       # evading restrictive
	__setattr__
        HTMLDocumentEvents2Class.__init__(self, obj)
        print 'Handler initialized'
    def onclick(self, *args):
        print 'onclick!', args
        seen +=1
    def Onclick(self, *args):
        print 'Onclick!', args
        seen +=1
    def Ononclick(self, eventIDispatch):
        print 'Ononclick ',
        seen += 1
        print seen
        # am not sure what this line is supposed to do
        eventIDispatch =
	win32com.client.gencache.EnsureDispatch(eventIDispatch)
        el = eventIDispatch.srcElement
        print "el = ", str(el)
        print 'clic on %s(%s) "%s", at (%d,%d)' % (
            el.tagName, el.id, el.innerText,
            eventIDispatch.clientX, eventIDispatch.clientY)

# ------------------------------------------------------------
# properties of event PyIDispatch object: (I think)
# -- all properties of IE4+ DOM 'event' object
# ------------------------------------------------------------

h = Handler(ie.Document)
print 'handler created'


while seen < 5:
    pythoncom.PumpWaitingMessages()

ie.Quit()

# ---- begin code ------------------------------------------------------


--
colin | i opened my windows 95 user manual and fell into a magical world.
roald |   -- greg kluzak, dishonourable mention, 1998 bulwer-lytton contest