def _unpack_response(response, cursor_id=None, codec_options=CodecOptions()):
"""Unpack a response from the database.
Check the response for errors and unpack, returning a dictionary
containing the response data.
Can raise CursorNotFound, NotMasterError, ExecutionTimeout, or
OperationFailure.
:Parameters:
- `response`: byte string as returned from the database
- `cursor_id` (optional): cursor_id we sent to get this response -
used for raising an informative exception when we get cursor id not
valid at server response
- `codec_options` (optional): an instance of
:class:`~bson.codec_options.CodecOptions`
"""
response_flag = struct.unpack("<i", response[:4])[0]
if response_flag & 1:
# Shouldn't get this response if we aren't doing a getMore
assert cursor_id is not None
# Fake a getMore command response. OP_GET_MORE provides no document.
msg = "Cursor not found, cursor id: %d" % (cursor_id,)
errobj = {"ok": 0, "errmsg": msg, "code": 43}
raise CursorNotFound(msg, 43, errobj)
elif response_flag & 2:
error_object = bson.BSON(response[20:]).decode()
# Fake the ok field if it doesn't exist.
error_object.setdefault("ok", 0)
if error_object["$err"].startswith("not master"):
raise NotMasterError(error_object["$err"], error_object)
elif error_object.get("code") == 50:
raise ExecutionTimeout(error_object.get("$err"),
error_object.get("code"),
error_object)
raise OperationFailure("database error: %s" %
error_object.get("$err"),
error_object.get("code"),
error_object)
result = {"cursor_id": struct.unpack("<q", response[4:12])[0],
"starting_from": struct.unpack("<i", response[12:16])[0],
"number_returned": struct.unpack("<i", response[16:20])[0],
"data": bson.decode_all(response[20:], codec_options)}
assert len(result["data"]) == result["number_returned"]
return result
评论列表
文章目录
