[python-win32] Threading problem

[Tim Roberts]

On Tue, 18 Apr 2006 15:01:10 +0200 (Central European Daylight Time),
"Aleksandar Cikota" <alexci at gmx.net> wrote:

>I have a problem with threading. 
>  
>

Why do you think it is a threading problem?  Does this exact program
work if you replace TestThread().start() with TestThread().run()?

Do you know for certain that the MaxIm objects are thread safe?  You're
creating the documents in one thread and using them in another.

>import win32com.client
>import time
>import os
>import threading
>Document = win32com.client.Dispatch('MaxIm.Document')
>Application = win32com.client.Dispatch('MaxIm.Application')
>p = win32com.client.dynamic.Dispatch('PinPoint.Plate')
>class TestThread (threading.Thread):
>    def run (self):
>      path_to_watch = "F:/Images/VRT/"  
>      before = dict ([(f, None) for f in os.listdir (path_to_watch)])
>      while 1:
>        time.sleep(2)
>        after2 = dict ([(f, None) for f in os.listdir (path_to_watch)])
>        added = [f for f in after2 if not f in before]
>  
>

As a side note, why do you turn these into dicts instead of just leaving
them as lists?  Given your usage, this seems like unnecessary extra
overhead.

And this code can't be right.  If there are multiple new files in the
directory, your "name" string will contain ALL of them, and it's
virtually certain that OpenFile won't know how to handle that.

>        if added:
>                name= ' ,'.join (added)
>                if str(name[-3:])=='fit':
>  
>

The "str" is unnecessary here.  "name" is already a string.

>                            print name
>                            Document.OpenFile('F:/Images/VRT/'+name) 
>                            Document.SaveFile('F:/Images/VRT/'+
>str(name[0:-4])+'.jpg', 6, 1024,2)
>                            Application.CloseAll()
>  
>

Does CloseAll close the application?  If so, doesn't that make the
Document objects evaporate?  Why don't you create the Document and
Application objects in your inner loop?  There's no sense in forcing an
instance of the application to stick around all the time when it's only
going to be asked to operate occasionally.

>                before = after2
>TestThread().start()
>

-- 
Tim Roberts, timr at probo.com
Providenza & Boekelheide, Inc.