Re: Patch for simple walk caching

On Thu, 9 Dec 2004 02:04:02 -0800, Ted Leung <[email protected]> wrote:
> 
> On Dec 7, 2004, at 7:56 AM, Bill Mill wrote:
> 
> > What if there was a function invalidate_cache(path) - and when a
> > plugin received an update to a page, it would invalidate the cache for
> > that path. From the client (plugin) side, ideally it would look
> > something like:
> >
> > if config['cache_dir']:                        #if using cache
> >     invalidate(path_to_changed_file)   #invalidate the path
> 
> I think this is the kind of client API I was looking for
> 
> >
> > the problem is from the cache server side - how does it figure out
> > which caches include that file? Does it open and search through all of
> > them? Can you launch a background thread from a CGI script? If you
> > can, then the user shouldn't experience too much delay, and his
> > changes should be implemented soon but not instantly. If not, he's
> > going to have to wait a while before his change is implemented.
> 
> Once you have a cache, then you have to manage it, which is why I didn't
> try to get all fancy.  It's especially tough in pyblosxom because there
> are so many legal paths.
> 

Well, that's all the fun for me. I'll see what I can hack up.

> 
> 
> >
> > The other thought I have would be to maintain a listing of what files
> > are in what caches. However, it's obviously really crucial to keep
> > overhead on the cache as low as possible, or the fix becomes the
> > problem.
> >
> > Also, as Wari said, permalinks don't even benefit from caching much.
> > The question is how to determine that something is a permalink - I
> > think I'll just set the cache up to ignore filelists with only one
> > entry.
> 
> I'm not all the concerned about permalinks, although I suppose I
> might be if my readership grew a lot (unlikely).  If my front page and
> RSS feed (which I haven't timed at all) go faster, then I'll be happy.
> 

It's really simple to modify the caching to work only for those two
files. Put this in your config.py:

py['cache_only'] = ['pyblosxom.cgi', 'root', 'index.rss'] # '' gets
changed to root

and then change

if config.get('cache_dir'):

to

p = http.get('PATH_INFO', '').lstrip('/') or 'root'
if config.get('cache_dir') and p in config.get('cache_only'):

Peace
Bill Mill
bill.mill at gmail.com


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