Re: Using invalidate_extension_info in python extensions

[Jason Field <jason jasonfield com>]

Thanks for the reply Alex. I've done a bit more investigation - see 
points below...

Alexander Larsson wrote:
> On Sat, 2006-11-18 at 00:07 +0000, Jason Field wrote:
>   
> > How is an extension writer supposed to ask Nautilus to re-scan a folder
> > for extension information? From what little I've gleaned from the
> > Nautilus wiki, I'm supposed to use the invalidate_extension_info call.
> > Only problem is, it doesn't seem to do much in my code!
> >
> > Is there some documentation on how it (and the other FileInfo methods)
> > are supposed to work?
> >     
>
> Hmm. That is supposed to work. If any user of the NautilusFile in
> nautilus has expressed an interest in the extension info for the file
> then if you invalidate it it should be re-read by nautilus.
>   
I take it there isn't any documentation other than the code then :). It 
looks at the moment like my threading code isn't getting executed 
properly, which is why I'm not seeing property updates. Are there 
supposed to be restrictions on thread activity instead nautilus python 
extension objects? If I do the following;

import threading
import time
import nautilus

class Test:
   def __init__(self):
       t = threading.Thread(target=self.ThreadProc)
       t.start()

   def ThreadProc(self):
       while True:
           print time.clock()
           time.sleep(0.5)
      
t = Test()

class MyExtension(nautilus.InfoProvider, nautilus.MenuProvider, 
nautilus.ColumnProvider):
   ... rest of extension here

I would expect that the time would get printed every half a second. What 
seems to happen is that I get a couple of prints at the start, and then 
a print every time I refresh the view in the Nautilus window. Is the 
nautilus extension keeping hold of the Python interpreter lock, or in 
some other way stopping Python executing other threads?

I tried working around this limitation by running a server in a separate 
instance of Python, and piping serialised file objects over a socket, 
but the NautilusFileInfo objects don't serialise correctly with pickle 
(it was a long shot :) ).
>   
> > My purpose is to get Nautilus to re-scan the file info every 30 seconds
> > or so. I'm writing the extension in Python, and the rest of the code
> > (emblems, menu items etc.) all works fine. I'm running Gnome 2.14.3
> > (Ubuntu distro).
> >     
>
> Strange. Just calling the invalidate_extension_info in a timeout should
> work. Might be a bug of some sort.
>   
Yep sorry my bad - I've got a feeling that the invalidate_extension_info 
will work fine once I sort the threading out.
> > Oh and a second quick question - is it possible to nest extension-added
> > menu items?
> >     
>
> In recent version (2.16 i think) there is support for this.
>   
Kick ass :)

Cheers,

Jason