Templetor's _find_file method should be available to contributed template support code

[foxbunny]

Most template engines by themselves do not support looking up templates without specifying an extension. Some of the patches that solve this for contributed template engine support code uses code similar to web.template.Render._find_file in order to provide Templetor-like behavior. It would be great if we didn't have this duplication by extracting _find_file and putting it somewhere like web.util where contrib template support code could use it.

For reference, _find_file currently looks like this:

def _findfile(self, path_prefix):
        p = [f for f in glob.glob(path_prefix + '.*') if not f.endswith('~')] # skip backup files
        p.sort() # sort the matches for deterministic order
        return p and p[0]

[foxbunny (bg-branko)]

If this is fixed, it would simplify fixes for these two tickets:

https://bugs.launchpad.net/webpy/+bug/252232
https://bugs.launchpad.net/webpy/+bug/525127

[foxbunny (bg-branko)]

Here's a patch that moves _findfile to web.utils, thus making it possible to reuse the code.

[Anand Chitipothu (anandology)]

Patch looks good.

findfile is too generic name. Can you think of anything better?

[foxbunny (bg-branko)]

How about prefix_lookup?

[foxbunny (bg-branko)]

prefixglob, globprefix, findbyprefix

[foxbunny (bg-branko)]

Settled for findbyprefix... Unique enough, but not too unique to scream for attention and raise questions. I think meaning can be derived from context.

[foxbunny (bg-branko)]

The last patch was not good. I forgot to fix the import in the template.py and add findbyprefix to __all__. Fixed now. Should work.