Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/proto/marshal/rules/bytes.py: 36%

1# Copyright (C) 2021 Google LLC 

2# 

3# Licensed under the Apache License, Version 2.0 (the "License"); 

4# you may not use this file except in compliance with the License. 

5# You may obtain a copy of the License at 

6# 

7# http://www.apache.org/licenses/LICENSE-2.0 

8# 

9# Unless required by applicable law or agreed to in writing, software 

10# distributed under the License is distributed on an "AS IS" BASIS, 

11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

12# See the License for the specific language governing permissions and 

13# limitations under the License. 

14 

15 

16import base64 

17 

18 

19class BytesRule: 

20 """A marshal between Python strings and protobuf bytes. 

21 

22 Note: this conversion is asymmetric because Python does have a bytes type. 

23 It is sometimes necessary to convert proto bytes fields to strings, e.g. for 

24 JSON encoding, marshalling a message to a dict. Because bytes fields can 

25 represent arbitrary data, bytes fields are base64 encoded when they need to 

26 be represented as strings. 

27 

28 It is necessary to have the conversion be bidirectional, i.e. 

29 my_message == MyMessage(MyMessage.to_dict(my_message)) 

30 

31 To accomplish this, we need to intercept assignments from strings and 

32 base64 decode them back into bytes. 

33 """ 

34 

35 def to_python(self, value, *, absent: bool = None): 

36 return value 

37 

38 def to_proto(self, value): 

39 if isinstance(value, str): 

40 value = value.encode("utf-8") 

41 value += b"=" * (4 - len(value) % 4) # padding 

42 value = base64.urlsafe_b64decode(value) 

43 

44 return value