falcon.routing.converters 源代码

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# Licensed under the Apache License, Version 2.0 (the "License");
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#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
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import abc
from datetime import datetime
from math import isfinite
from typing import Optional
import uuid

__all__ = (
    'BaseConverter',
    'DateTimeConverter',
    'FloatConverter',
    'IntConverter',
    'UUIDConverter',
)


# PERF(kgriffs): Avoid an extra namespace lookup when using this function
strptime = datetime.strptime


[文档]class BaseConverter(metaclass=abc.ABCMeta): """Abstract base class for URI template field converters.""" CONSUME_MULTIPLE_SEGMENTS = False """When set to ``True`` it indicates that this converter will consume multiple URL path segments. Currently a converter with ``CONSUME_MULTIPLE_SEGMENTS=True`` must be at the end of the URL template effectively meaning that it will consume all of the remaining URL path segments. """
[文档] @abc.abstractmethod # pragma: no cover def convert(self, value): """Convert a URI template field value to another format or type. Args: value (str or List[str]): Original string to convert. If ``CONSUME_MULTIPLE_SEGMENTS=True`` this value is a list of strings containing the path segments matched by the converter. Returns: object: Converted field value, or ``None`` if the field can not be converted. """
def _consumes_multiple_segments(converter): return getattr(converter, 'CONSUME_MULTIPLE_SEGMENTS', False)
[文档]class IntConverter(BaseConverter): """Converts a field value to an int. Identifier: `int` Keyword Args: num_digits (int): Require the value to have the given number of digits. min (int): Reject the value if it is less than this number. max (int): Reject the value if it is greater than this number. """ __slots__ = ('_num_digits', '_min', '_max') def __init__(self, num_digits=None, min=None, max=None): if num_digits is not None and num_digits < 1: raise ValueError('num_digits must be at least 1') self._num_digits = num_digits self._min = min self._max = max
[文档] def convert(self, value): if self._num_digits is not None and len(value) != self._num_digits: return None # NOTE(kgriffs): int() will accept numbers with preceding or # trailing whitespace, so we need to do our own check. Using # strip() is faster than either a regex or a series of or'd # membership checks via "in", esp. as the length of contiguous # numbers in the value grows. if value.strip() != value: return None try: value = int(value) except ValueError: return None return self._validate_min_max_value(value)
def _validate_min_max_value(self, value): if self._min is not None and value < self._min: return None if self._max is not None and value > self._max: return None return value
[文档]class FloatConverter(IntConverter): """Converts a field value to an float. Identifier: `float` Keyword Args: min (float): Reject the value if it is less than this number. max (float): Reject the value if it is greater than this number. finite (bool) : Determines whether or not to only match ordinary finite numbers (default: ``True``). Set to ``False`` to match nan, inf, and -inf in addition to finite numbers. """ __slots__ = '_finite' def __init__( self, min: Optional[float] = None, max: Optional[float] = None, finite: bool = True, ): self._min = min self._max = max self._finite = finite if finite is not None else True
[文档] def convert(self, value: str): if value.strip() != value: return None try: converted = float(value) if self._finite and not isfinite(converted): return None except ValueError: return None return self._validate_min_max_value(converted)
[文档]class DateTimeConverter(BaseConverter): """Converts a field value to a datetime. Identifier: `dt` Keyword Args: format_string (str): String used to parse the field value into a datetime. Any format recognized by strptime() is supported (default ``'%Y-%m-%dT%H:%M:%SZ'``). """ __slots__ = ('_format_string',) def __init__(self, format_string='%Y-%m-%dT%H:%M:%SZ'): self._format_string = format_string
[文档] def convert(self, value): try: return strptime(value, self._format_string) except ValueError: return None
[文档]class UUIDConverter(BaseConverter): """Converts a field value to a uuid.UUID. Identifier: `uuid` In order to be converted, the field value must consist of a string of 32 hexadecimal digits, as defined in RFC 4122, Section 3. Note, however, that hyphens and the URN prefix are optional. """
[文档] def convert(self, value): try: return uuid.UUID(value) except ValueError: return None
[文档]class PathConverter(BaseConverter): """Field converted used to match the rest of the path. This field converter matches the remainder of the URL path, returning it as a string. This converter is currently supported only when used at the end of the URL template. The classic routing rules of falcon apply also to this converter: considering the template ``'/foo/bar/{matched_path:path}'``, the path ``'/foo/bar'`` will *not* match the route; ``'/foo/bar/'`` will match, producing ``matched_path=''``, when :attr:`~falcon.RequestOptions.strip_url_path_trailing_slash` is ``False`` (the default), while it will *not* match when that option is ``True``. (See also: :ref:`trailing_slash_in_path`) """ CONSUME_MULTIPLE_SEGMENTS = True
[文档] def convert(self, value): return '/'.join(value)
BUILTIN = ( ('int', IntConverter), ('dt', DateTimeConverter), ('uuid', UUIDConverter), ('float', FloatConverter), ('path', PathConverter), )