1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
import copy
from abc import ABC, abstractmethod # pylint: disable=[no-name-in-module]
from typing import Any, List, Literal, Optional, Tuple, Union
from knot_resolver.utils.modeling.base_schema import BaseSchema, map_object
from knot_resolver.utils.modeling.json_pointer import json_ptr_resolve
class PatchError(Exception):
pass
class Op(BaseSchema, ABC):
@abstractmethod
def eval(self, fakeroot: Any) -> Any:
"""
modifies the given fakeroot, returns a new one
"""
def _resolve_ptr(self, fakeroot: Any, ptr: str) -> Tuple[Any, Any, Union[str, int, None]]:
# Lookup tree part based on the given JSON pointer
parent, obj, token = json_ptr_resolve(fakeroot["root"], ptr)
# the lookup was on pure data, wrap the results in QueryTree
if parent is None:
parent = fakeroot
token = "root"
assert token is not None
return parent, obj, token
class AddOp(Op):
op: Literal["add"]
path: str
value: Any
def eval(self, fakeroot: Any) -> Any:
parent, _obj, token = self._resolve_ptr(fakeroot, self.path)
if isinstance(parent, dict):
parent[token] = self.value
elif isinstance(parent, list):
if token == "-":
parent.append(self.value)
else:
assert isinstance(token, int)
parent.insert(token, self.value)
else:
raise AssertionError("never happens")
return fakeroot
class RemoveOp(Op):
op: Literal["remove"]
path: str
def eval(self, fakeroot: Any) -> Any:
parent, _obj, token = self._resolve_ptr(fakeroot, self.path)
del parent[token]
return fakeroot
class ReplaceOp(Op):
op: Literal["replace"]
path: str
value: str
def eval(self, fakeroot: Any) -> Any:
parent, obj, token = self._resolve_ptr(fakeroot, self.path)
if obj is None:
raise PatchError("the value you are trying to replace is null")
parent[token] = self.value
return fakeroot
class MoveOp(Op):
op: Literal["move"]
source: str
path: str
def _source(self, source):
if "from" not in source:
raise ValueError("missing property 'from' in 'move' JSON patch operation")
return str(source["from"])
def eval(self, fakeroot: Any) -> Any:
if self.path.startswith(self.source):
raise PatchError("can't move value into itself")
_parent, obj, _token = self._resolve_ptr(fakeroot, self.source)
newobj = copy.deepcopy(obj)
fakeroot = RemoveOp({"op": "remove", "path": self.source}).eval(fakeroot)
return AddOp({"path": self.path, "value": newobj, "op": "add"}).eval(fakeroot)
class CopyOp(Op):
op: Literal["copy"]
source: str
path: str
def _source(self, source):
if "from" not in source:
raise ValueError("missing property 'from' in 'copy' JSON patch operation")
return str(source["from"])
def eval(self, fakeroot: Any) -> Any:
_parent, obj, _token = self._resolve_ptr(fakeroot, self.source)
newobj = copy.deepcopy(obj)
return AddOp({"path": self.path, "value": newobj, "op": "add"}).eval(fakeroot)
class TestOp(Op):
op: Literal["test"]
path: str
value: Any
def eval(self, fakeroot: Any) -> Any:
_parent, obj, _token = self._resolve_ptr(fakeroot, self.path)
if obj != self.value:
raise PatchError("test failed")
return fakeroot
def query(
original: Any, method: Literal["get", "delete", "put", "patch"], ptr: str, payload: Any
) -> Tuple[Any, Optional[Any]]:
########################################
# Prepare data we will be working on
# First of all, we consider the original data to be immutable. So we need to make a copy
# in order to freely mutate them
dataroot = copy.deepcopy(original)
# To simplify referencing the root, create a fake root node
fakeroot = {"root": dataroot}
#########################################
# Handle the actual requested operation
# get = return what the path selector picks
if method == "get":
parent, obj, token = json_ptr_resolve(fakeroot, f"/root{ptr}")
return fakeroot["root"], obj
if method == "delete":
fakeroot = RemoveOp({"op": "remove", "path": ptr}).eval(fakeroot)
return fakeroot["root"], None
if method == "put":
parent, obj, token = json_ptr_resolve(fakeroot, f"/root{ptr}")
assert parent is not None # we know this due to the fakeroot
if isinstance(parent, list) and token == "-":
parent.append(payload)
else:
parent[token] = payload
return fakeroot["root"], None
if method == "patch":
tp = List[Union[AddOp, RemoveOp, MoveOp, CopyOp, TestOp, ReplaceOp]]
transaction: tp = map_object(tp, payload)
for i, op in enumerate(transaction):
try:
fakeroot = op.eval(fakeroot)
except PatchError as e:
raise ValueError(f"json patch transaction failed on step {i}") from e
return fakeroot["root"], None
raise AssertionError("invalid operation, never happens")
|
