Determining if a file is locked in Windows

[elake]

MatthewWarren wrote:
> elake wrote:
> > Larry Bates wrote:
> > > elake wrote:
> > > > I found this thread about a pst file in Windows being locked and I am
> > > > having the same issue.
> > > >
> >
> > > > http://groups.google.com/group/comp.lang.python/browse_thread/thread/d3dee5550b6d3652/ed00977acf62484f?lnk=gst&q=%27copying+locked+files%27&rnum=1
> > > >
> > > > The problem is that I have a script that can find the pst files on
> > > > every machine in my network and back them up to a server for safe
> > > > keeping. The problem is that when Outlook is running it locks the file
> > > > and will not allow me to copy it to the destination. I am using the
> > > > shutil module for the copy.
> > > >
> > > > Is there a way to first determine if the file is locked and then do the
> > > > copy if it isn't? I thought about looking to see if Outlook.exe is
> > > > running but the machines are shared and the process could be running
> > > > but with a different pst file in use.
> > > >
> > > > Thanks in advance
> > > >
> > > Try the copy and catch the exception instead.
> > >
> > > -Larry Bates
> >
> > Larry thanks for your suggestion. this is what I tried:
> >
> > #!/usr/bin/env python
> >
> > import os, shutil
> >
> > path = 'c:\documents and settings\username\Local Settings\Application
> > Data\Microsoft\Outlook'
> >
> > src = 'Outlook.pst'
> > dst = 'test.pst'
> >
> > os.chdir(path)
> >
> > try:
> >     shutil.copy2(src, dst)
> > except IOError:
> >     print 'Must be locked by Outlook'
> >
> > print 'Finished'
> >
> > The problem is that even though I catch the IOError it overwrites the
> > dst file and makes it 0kb. This is going to be for backing these files
> > up and it wont be good to overwrite the backup with a bad copy.
> >
> > Is there another way to do this that I am missing. I am still kind of
> > new to Python. If i could tell that outlook had the file locked before
> > I tried the copy then I think that it would be prevented.
>
> maybe try and open the file for reading first, then if it opens ok,
> just close it and do the copy?

I tried to do that and it did let me open it without an error. Here is
what I have done now and it seems work.

def copyFile(src, dst):
    if os.path.isfile(dst):
        shutil.copy2(dst, dst_bak)
        try:
            shutil.copy2(src, dst)
        except IOError:
            if os.path.isfile(dst_bak):
                shutil.copy2(dst_bak, dst)
                os.remove(dst_bak)
    else:
        try:
            shutil.copy2(src, dst)
        except IOError:
            if os.path.isfile(dst_bak):
                shutil.copy2(dst_bak, dst)

It check to see if the dst file is there first and them makes a backup
of it first. That way if the copy goes bad then there is still a backup
of it. Do you see anywhere that I could have done  this
better/differently?