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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
# SPDX-License-Identifier: AGPL-3.0-or-later
"""Calculate mathematical expressions using :py:obj:`ast.parse` (mode="eval")."""
from __future__ import annotations
import typing
import ast
import re
import operator
import multiprocessing
import babel
import babel.numbers
from flask_babel import gettext
from searx.result_types import EngineResults
from searx.plugins import Plugin, PluginInfo
if typing.TYPE_CHECKING:
from searx.search import SearchWithPlugins
from searx.extended_types import SXNG_Request
from searx.plugins import PluginCfg
class SXNGPlugin(Plugin):
"""Plugin converts strings to different hash digests. The results are
displayed in area for the "answers".
"""
id = "calculator"
def __init__(self, plg_cfg: "PluginCfg") -> None:
super().__init__(plg_cfg)
self.info = PluginInfo(
id=self.id,
name=gettext("Basic Calculator"),
description=gettext("Calculate mathematical expressions via the search bar"),
preference_section="general",
)
def post_search(self, request: "SXNG_Request", search: "SearchWithPlugins") -> EngineResults:
results = EngineResults()
# only show the result of the expression on the first page
if search.search_query.pageno > 1:
return results
query = search.search_query.query
# in order to avoid DoS attacks with long expressions, ignore long expressions
if len(query) > 100:
return results
# replace commonly used math operators with their proper Python operator
query = query.replace("x", "*").replace(":", "/")
# use UI language
ui_locale = babel.Locale.parse(request.preferences.get_value("locale"), sep="-")
# parse the number system in a localized way
def _decimal(match: re.Match) -> str:
val = match.string[match.start() : match.end()]
val = babel.numbers.parse_decimal(val, ui_locale, numbering_system="latn")
return str(val)
decimal = ui_locale.number_symbols["latn"]["decimal"]
group = ui_locale.number_symbols["latn"]["group"]
query = re.sub(f"[0-9]+[{decimal}|{group}][0-9]+[{decimal}|{group}]?[0-9]?", _decimal, query)
# only numbers and math operators are accepted
if any(str.isalpha(c) for c in query):
return results
# in python, powers are calculated via **
query_py_formatted = query.replace("^", "**")
# Prevent the runtime from being longer than 50 ms
res = timeout_func(0.05, _eval_expr, query_py_formatted)
if res is None or res[0] == "":
return results
res, is_boolean = res
if is_boolean:
res = "True" if res != 0 else "False"
else:
res = babel.numbers.format_decimal(res, locale=ui_locale)
results.add(results.types.Answer(answer=f"{search.search_query.query} = {res}"))
return results
def _compare(ops: list[ast.cmpop], values: list[int | float]) -> int:
"""
2 < 3 becomes ops=[ast.Lt] and values=[2,3]
2 < 3 <= 4 becomes ops=[ast.Lt, ast.LtE] and values=[2,3, 4]
"""
for op, a, b in zip(ops, values, values[1:]): # pylint: disable=invalid-name
if isinstance(op, ast.Eq) and a == b:
continue
if isinstance(op, ast.NotEq) and a != b:
continue
if isinstance(op, ast.Lt) and a < b:
continue
if isinstance(op, ast.LtE) and a <= b:
continue
if isinstance(op, ast.Gt) and a > b:
continue
if isinstance(op, ast.GtE) and a >= b:
continue
# Ignore impossible ops:
# * ast.Is
# * ast.IsNot
# * ast.In
# * ast.NotIn
# the result is False for a and b and operation op
return 0
# the results for all the ops are True
return 1
operators: dict[type, typing.Callable] = {
ast.Add: operator.add,
ast.Sub: operator.sub,
ast.Mult: operator.mul,
ast.Div: operator.truediv,
ast.Pow: operator.pow,
ast.BitXor: operator.xor,
ast.BitOr: operator.or_,
ast.BitAnd: operator.and_,
ast.USub: operator.neg,
ast.RShift: operator.rshift,
ast.LShift: operator.lshift,
ast.Mod: operator.mod,
ast.Compare: _compare,
}
# with multiprocessing.get_context("fork") we are ready for Py3.14 (by emulating
# the old behavior "fork") but it will not solve the core problem of fork, nor
# will it remove the deprecation warnings in py3.12 & py3.13. Issue is
# ddiscussed here: https://github.com/searxng/searxng/issues/4159
mp_fork = multiprocessing.get_context("fork")
def _eval_expr(expr):
"""
Evaluates the given textual expression.
Returns a tuple of (numericResult, isBooleanResult).
>>> _eval_expr('2^6')
64, False
>>> _eval_expr('2**6')
64, False
>>> _eval_expr('1 + 2*3**(4^5) / (6 + -7)')
-5.0, False
>>> _eval_expr('1 < 3')
1, True
>>> _eval_expr('5 < 3')
0, True
>>> _eval_expr('17 == 11+1+5 == 7+5+5')
1, True
"""
try:
root_expr = ast.parse(expr, mode='eval').body
return _eval(root_expr), isinstance(root_expr, ast.Compare)
except ZeroDivisionError:
# This is undefined
return "", False
def _eval(node):
if isinstance(node, ast.Constant) and isinstance(node.value, (int, float)):
return node.value
if isinstance(node, ast.BinOp):
return operators[type(node.op)](_eval(node.left), _eval(node.right))
if isinstance(node, ast.UnaryOp):
return operators[type(node.op)](_eval(node.operand))
if isinstance(node, ast.Compare):
return _compare(node.ops, [_eval(node.left)] + [_eval(c) for c in node.comparators])
raise TypeError(node)
def handler(q: multiprocessing.Queue, func, args, **kwargs): # pylint:disable=invalid-name
try:
q.put(func(*args, **kwargs))
except:
q.put(None)
raise
def timeout_func(timeout, func, *args, **kwargs):
que = mp_fork.Queue()
p = mp_fork.Process(target=handler, args=(que, func, args), kwargs=kwargs)
p.start()
p.join(timeout=timeout)
ret_val = None
# pylint: disable=used-before-assignment,undefined-variable
if not p.is_alive():
ret_val = que.get()
else:
logger.debug("terminate function after timeout is exceeded") # type: ignore
p.terminate()
p.join()
p.close()
return ret_val
|
