51 lines
1.8 KiB
Python
51 lines
1.8 KiB
Python
# Copyright (c) Microsoft. All rights reserved.
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import ast
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import sys
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from urllib.parse import quote_plus
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if sys.version_info >= (3, 12):
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from typing import override # pragma: no cover
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else:
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from typing_extensions import override # pragma: no cover
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class SearchLambdaVisitor(ast.NodeVisitor):
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"""Visitor to parse a lambda function for Brave and Google Search filters."""
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def __init__(self, valid_parameters: list[str]):
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"""Initialize the visitor with a list of valid parameters."""
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self.filters: list[dict[str, str]] = []
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self.valid_parameters = valid_parameters
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@override
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def visit_Lambda(self, node):
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self.visit(node.body)
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@override
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def visit_Compare(self, node):
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# Only support x.FIELD == VALUE
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if not (isinstance(node.left, ast.Attribute) and isinstance(node.left.value, ast.Name)):
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raise NotImplementedError("Left side must be x.FIELD.")
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field = node.left.attr
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if not (len(node.ops) == 1 and isinstance(node.ops[0], ast.Eq)):
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raise NotImplementedError("Only == comparisons are supported.")
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right = node.comparators[0]
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if isinstance(right, ast.Constant):
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if right.value is None:
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raise NotImplementedError("None values are not supported.")
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value = str(right.value)
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else:
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raise NotImplementedError("Only constant values are supported on the right side.")
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if field not in self.valid_parameters:
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raise ValueError(f"Field '{field}' is not supported.")
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self.filters.append({field: quote_plus(value)})
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@override
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def visit_BoolOp(self, node):
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if not isinstance(node.op, ast.And):
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raise NotImplementedError("Only 'and' of == comparisons is supported.")
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for v in node.values:
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self.visit(v)
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