I don’t think that this task is a “wheel” (so to speak). But it is something which you can easily achieve by means of the tools you mentioned:
import os
import json
def path_to_dict(path):
d = {'name': os.path.basename(path)}
if os.path.isdir(path):
d['type'] = "directory"
d['children'] = [path_to_dict(os.path.join(path,x)) for x in os.listdir\
(path)]
else:
d['type'] = "file"
return d
print json.dumps(path_to_dict('.'))