Files
Nominatim/nominatim/tokenizer/sanitizers/config.py
2023-08-25 21:40:20 +02:00

152 lines
6.4 KiB
Python

# SPDX-License-Identifier: GPL-2.0-only
#
# This file is part of Nominatim. (https://nominatim.org)
#
# Copyright (C) 2022 by the Nominatim developer community.
# For a full list of authors see the git log.
"""
Configuration for Sanitizers.
"""
from typing import Sequence, Union, Optional, Pattern, Callable, Any, TYPE_CHECKING
from collections import UserDict
import re
from nominatim.errors import UsageError
# working around missing generics in Python < 3.8
# See https://github.com/python/typing/issues/60#issuecomment-869757075
if TYPE_CHECKING:
_BaseUserDict = UserDict[str, Any]
else:
_BaseUserDict = UserDict
class SanitizerConfig(_BaseUserDict):
""" The `SanitizerConfig` class is a read-only dictionary
with configuration options for the sanitizer.
In addition to the usual dictionary functions, the class provides
accessors to standard sanitizer options that are used by many of the
sanitizers.
"""
def get_string_list(self, param: str, default: Sequence[str] = tuple()) -> Sequence[str]:
""" Extract a configuration parameter as a string list.
Arguments:
param: Name of the configuration parameter.
default: Takes a tuple or list of strings which will
be returned if the parameter is missing in the
sanitizer configuration.
Note that if this default parameter is not
provided then an empty list is returned.
Returns:
If the parameter value is a simple string, it is returned as a
one-item list. If the parameter value does not exist, the given
default is returned. If the parameter value is a list, it is
checked to contain only strings before being returned.
"""
values = self.data.get(param, None)
if values is None:
return list(default)
if isinstance(values, str):
return [values] if values else []
if not isinstance(values, (list, tuple)):
raise UsageError(f"Parameter '{param}' must be string or list of strings.")
if any(not isinstance(value, str) for value in values):
raise UsageError(f"Parameter '{param}' must be string or list of strings.")
return values
def get_bool(self, param: str, default: Optional[bool] = None) -> bool:
""" Extract a configuration parameter as a boolean.
Arguments:
param: Name of the configuration parameter. The parameter must
contain one of the yaml boolean values or an
UsageError will be raised.
default: Value to return, when the parameter is missing.
When set to `None`, the parameter must be defined.
Returns:
Boolean value of the given parameter.
"""
value = self.data.get(param, default)
if not isinstance(value, bool):
raise UsageError(f"Parameter '{param}' must be a boolean value ('yes' or 'no').")
return value
def get_delimiter(self, default: str = ',;') -> Pattern[str]:
""" Return the 'delimiters' parameter in the configuration as a
compiled regular expression that can be used to split strings on
these delimiters.
Arguments:
default: Delimiters to be used when 'delimiters' parameter
is not explicitly configured.
Returns:
A regular expression pattern which can be used to
split a string. The regular expression makes sure that the
resulting names are stripped and that repeated delimiters
are ignored. It may still create empty fields on occasion. The
code needs to filter those.
"""
delimiter_set = set(self.data.get('delimiters', default))
if not delimiter_set:
raise UsageError("Empty 'delimiter' parameter not allowed for sanitizer.")
return re.compile('\\s*[{}]+\\s*'.format(''.join('\\' + d for d in delimiter_set)))
def get_filter(self, param: str, default: Union[str, Sequence[str]] = 'PASS_ALL'
) -> Callable[[str], bool]:
""" Returns a filter function for the given parameter of the sanitizer
configuration.
The value provided for the parameter in sanitizer configuration
should be a string or list of strings, where each string is a regular
expression. These regular expressions will later be used by the
filter function to filter strings.
Arguments:
param: The parameter for which the filter function
will be created.
default: Defines the behaviour of filter function if
parameter is missing in the sanitizer configuration.
Takes a string(PASS_ALL or FAIL_ALL) or a list of strings.
Any other value of string or an empty list is not allowed,
and will raise a ValueError. If the value is PASS_ALL, the filter
function will let all strings to pass, if the value is FAIL_ALL,
filter function will let no strings to pass.
If value provided is a list of strings each string
is treated as a regular expression. In this case these regular
expressions will be used by the filter function.
By default allow filter function to let all strings pass.
Returns:
A filter function that takes a target string as the argument and
returns True if it fully matches any of the regular expressions
otherwise returns False.
"""
filters = self.get_string_list(param) or default
if filters == 'PASS_ALL':
return lambda _: True
if filters == 'FAIL_ALL':
return lambda _: False
if filters and isinstance(filters, (list, tuple)):
regexes = [re.compile(regex) for regex in filters]
return lambda target: any(regex.fullmatch(target) for regex in regexes)
raise ValueError("Default parameter must be a non-empty list or a string value \
('PASS_ALL' or 'FAIL_ALL').")