Cleanup when a object dies

[Benjamin]

I writing writing a class to allow settings (options, preferences) to
written file in a cross platform manner. I'm unsure how to go a about
syncing the data to disk. Of course, it's horribly inefficient to
write the data every time something changes a value, however I don't
see how I can do it on deletion. I've read that __del__ methods should
be avoided. So am I just going to have to force the client of my
object to call sync when they're done?

 

[Raymond Hettinger]

I writing writing a class to allow settings (options, preferences) to
written file in a cross platform manner. I'm unsure how to go a about
syncing the data to disk. Of course, it's horribly inefficient to
write the data every time something changes a value, however I don't
see how I can do it on deletion. I've read that __del__ methods should
be avoided. So am I just going to have to force the client of my
object to call sync when they're done?

Lots of ways
1. Try the atexit module
2. Use a weakref callback
3. Embed a client callback in a try/finally.
4. Or, like you said, have the client call a sync() method -- this is
explicit and gives the client control over when data is written.

Raymond

 

[Benjamin]

Lots of ways
1. Try the atexit module
2. Use a weakref callback

So, I can keep a global list weakrefs to all the objects of my class
that have been created. Then have the callback call sync on them?