'custom_retrieve to override web2py DAL\'s standard retrieve,
as that checks filenames for uuids, so doesn\'t work with
pre-populated files in static'

@staticmethod
def gis_cache2_retrieve(filename, path=None):

    if (not path):
        path = current.db.gis_cache2.file.uploadfolder
    f = open(os.path.join(path, filename), 'rb')
    return (filename, f)
