def write_metadata_cache(self, storage, bl):
from calibre.devices.mtp.books import JSONCodec
if bl.storage_id != storage.storage_id:
# Just a sanity check, should never happen
return
json_codec = JSONCodec()
stream = SpooledTemporaryFile(10*(1024**2))
json_codec.encode_to_file(stream, bl)
size = stream.tell()
stream.seek(0)
self.put_calibre_file(storage, 'metadata', stream, size)
