Coverage for python/lsst/daf/butler/json.py: 53%

1# This file is part of daf_butler. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (http://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This software is dual licensed under the GNU General Public License and also 

10# under a 3-clause BSD license. Recipients may choose which of these licenses 

11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt, 

12# respectively. If you choose the GPL option then the following text applies 

13# (but note that there is still no warranty even if you opt for BSD instead): 

14# 

15# This program is free software: you can redistribute it and/or modify 

16# it under the terms of the GNU General Public License as published by 

17# the Free Software Foundation, either version 3 of the License, or 

18# (at your option) any later version. 

19# 

20# This program is distributed in the hope that it will be useful, 

21# but WITHOUT ANY WARRANTY; without even the implied warranty of 

22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

23# GNU General Public License for more details. 

24# 

25# You should have received a copy of the GNU General Public License 

26# along with this program. If not, see <http://www.gnu.org/licenses/>. 

27 

28from __future__ import annotations 

29 

30__all__ = ("to_json_generic", "from_json_generic", "to_json_pydantic", "from_json_pydantic") 

31 

32import json 

33from typing import TYPE_CHECKING, Any, Protocol, Type 

34 

35if TYPE_CHECKING: 

36 from .dimensions import DimensionUniverse 

37 from .registry import Registry 

38 

39 

40class SupportsSimple(Protocol): 

41 """Protocol defining the methods required to support the standard 

42 serialization using "simple" methods names. 

43 """ 

44 

45 _serializedType: Type 

46 

47 def to_simple(self, minimal: bool) -> Any: ... 47 ↛ exitline 47 didn't jump to line 47, because

48 

49 @classmethod 

50 def from_simple( 50 ↛ exitline 50 didn't jump to the function exit

51 cls, simple: Any, universe: DimensionUniverse | None = None, registry: Registry | None = None 

52 ) -> SupportsSimple: ... 

53 

54 

55def to_json_pydantic(self: SupportsSimple, minimal: bool = False) -> str: 

56 """Convert this class to JSON assuming that the ``to_simple()`` returns 

57 a pydantic model. 

58 

59 Parameters 

60 ---------- 

61 minimal : `bool` 

62 Return minimal possible representation. 

63 """ 

64 return self.to_simple(minimal=minimal).model_dump_json(exclude_defaults=True, exclude_unset=True) 

65 

66 

67def from_json_pydantic( 

68 cls_: type[SupportsSimple], 

69 json_str: str, 

70 universe: DimensionUniverse | None = None, 

71 registry: Registry | None = None, 

72) -> SupportsSimple: 

73 """Convert from JSON to a pydantic model. 

74 

75 Parameters 

76 ---------- 

77 cls_ : `type` of `SupportsSimple` 

78 The Python type being created. 

79 json_str : `str` 

80 The JSON string representing this object. 

81 universe : `DimensionUniverse` or `None`, optional 

82 The universe required to instantiate some models. Required if 

83 ``registry`` is `None`. 

84 registry : `Registry` or `None`, optional 

85 Registry from which to obtain the dimension universe if an explicit 

86 universe has not been given. 

87 

88 Returns 

89 ------- 

90 model : `SupportsSimple` 

91 Pydantic model constructed from JSON and validated. 

92 """ 

93 simple = cls_._serializedType.model_validate_json(json_str) 

94 try: 

95 return cls_.from_simple(simple, universe=universe, registry=registry) 

96 except AttributeError as e: 

97 raise AttributeError(f"JSON deserialization requires {cls_} has a from_simple() class method") from e 

98 

99 

100def to_json_generic(self: SupportsSimple, minimal: bool = False) -> str: 

101 """Convert this class to JSON form. 

102 

103 The class type is not recorded in the JSON so the JSON decoder 

104 must know which class is represented. 

105 

106 Parameters 

107 ---------- 

108 minimal : `bool`, optional 

109 Use minimal serialization. Requires Registry to convert 

110 back to a full type. 

111 

112 Returns 

113 ------- 

114 json : `str` 

115 The class in JSON string format. 

116 """ 

117 # For now use the core json library to convert a dict to JSON 

118 # for us. 

119 return json.dumps(self.to_simple(minimal=minimal)) 

120 

121 

122def from_json_generic( 

123 cls: type[SupportsSimple], 

124 json_str: str, 

125 universe: DimensionUniverse | None = None, 

126 registry: Registry | None = None, 

127) -> SupportsSimple: 

128 """Return new class from JSON string. 

129 

130 Converts a JSON string created by `to_json` and return 

131 something of the supplied class. 

132 

133 Parameters 

134 ---------- 

135 json_str : `str` 

136 Representation of the dimensions in JSON format as created 

137 by `to_json()`. 

138 universe : `DimensionUniverse`, optional 

139 The special graph of all known dimensions. Passed directly 

140 to `from_simple()`. 

141 registry : `lsst.daf.butler.Registry`, optional 

142 Registry to use to convert simple name of a DatasetType to 

143 a full `DatasetType`. Passed directly to `from_simple()`. 

144 

145 Returns 

146 ------- 

147 constructed : Any 

148 Newly-constructed object. 

149 """ 

150 simple = json.loads(json_str) 

151 try: 

152 return cls.from_simple(simple, universe=universe, registry=registry) 

153 except AttributeError as e: 

154 raise AttributeError(f"JSON deserialization requires {cls} has a from_simple() class method") from e