done

lib/python3.11/site-packages/werkzeug/datastructures/cache_control.py

@@ -0,0 +1,273 @@
+from __future__ import annotations
+
+import collections.abc as cabc
+import typing as t
+from inspect import cleandoc
+
+from .mixins import ImmutableDictMixin
+from .structures import CallbackDict
+
+
+def cache_control_property(
+    key: str, empty: t.Any, type: type[t.Any] | None, *, doc: str | None = None
+) -> t.Any:
+    """Return a new property object for a cache header. Useful if you
+    want to add support for a cache extension in a subclass.
+
+    :param key: The attribute name present in the parsed cache-control header dict.
+    :param empty: The value to use if the key is present without a value.
+    :param type: The type to convert the string value to instead of a string. If
+        conversion raises a ``ValueError``, the returned value is ``None``.
+    :param doc: The docstring for the property. If not given, it is generated
+        based on the other params.
+
+    .. versionchanged:: 3.1
+        Added the ``doc`` param.
+
+    .. versionchanged:: 2.0
+        Renamed from ``cache_property``.
+    """
+    if doc is None:
+        parts = [f"The ``{key}`` attribute."]
+
+        if type is bool:
+            parts.append("A ``bool``, either present or not.")
+        else:
+            if type is None:
+                parts.append("A ``str``,")
+            else:
+                parts.append(f"A ``{type.__name__}``,")
+
+            if empty is not None:
+                parts.append(f"``{empty!r}`` if present with no value,")
+
+            parts.append("or ``None`` if not present.")
+
+        doc = " ".join(parts)
+
+    return property(
+        lambda x: x._get_cache_value(key, empty, type),
+        lambda x, v: x._set_cache_value(key, v, type),
+        lambda x: x._del_cache_value(key),
+        doc=cleandoc(doc),
+    )
+
+
+class _CacheControl(CallbackDict[str, t.Optional[str]]):
+    """Subclass of a dict that stores values for a Cache-Control header.  It
+    has accessors for all the cache-control directives specified in RFC 2616.
+    The class does not differentiate between request and response directives.
+
+    Because the cache-control directives in the HTTP header use dashes the
+    python descriptors use underscores for that.
+
+    To get a header of the :class:`CacheControl` object again you can convert
+    the object into a string or call the :meth:`to_header` method.  If you plan
+    to subclass it and add your own items have a look at the sourcecode for
+    that class.
+
+    .. versionchanged:: 3.1
+        Dict values are always ``str | None``. Setting properties will
+        convert the value to a string. Setting a non-bool property to
+        ``False`` is equivalent to setting it to ``None``. Getting typed
+        properties will return ``None`` if conversion raises
+        ``ValueError``, rather than the string.
+
+    .. versionchanged:: 2.1
+        Setting int properties such as ``max_age`` will convert the
+        value to an int.
+
+    .. versionchanged:: 0.4
+       Setting ``no_cache`` or ``private`` to ``True`` will set the
+       implicit value ``"*"``.
+    """
+
+    no_store: bool = cache_control_property("no-store", None, bool)
+    max_age: int | None = cache_control_property("max-age", None, int)
+    no_transform: bool = cache_control_property("no-transform", None, bool)
+    stale_if_error: int | None = cache_control_property("stale-if-error", None, int)
+
+    def __init__(
+        self,
+        values: cabc.Mapping[str, t.Any] | cabc.Iterable[tuple[str, t.Any]] | None = (),
+        on_update: cabc.Callable[[_CacheControl], None] | None = None,
+    ):
+        super().__init__(values, on_update)
+        self.provided = values is not None
+
+    def _get_cache_value(
+        self, key: str, empty: t.Any, type: type[t.Any] | None
+    ) -> t.Any:
+        """Used internally by the accessor properties."""
+        if type is bool:
+            return key in self
+
+        if key not in self:
+            return None
+
+        if (value := self[key]) is None:
+            return empty
+
+        if type is not None:
+            try:
+                value = type(value)
+            except ValueError:
+                return None
+
+        return value
+
+    def _set_cache_value(
+        self, key: str, value: t.Any, type: type[t.Any] | None
+    ) -> None:
+        """Used internally by the accessor properties."""
+        if type is bool:
+            if value:
+                self[key] = None
+            else:
+                self.pop(key, None)
+        elif value is None or value is False:
+            self.pop(key, None)
+        elif value is True:
+            self[key] = None
+        else:
+            if type is not None:
+                value = type(value)
+
+            self[key] = str(value)
+
+    def _del_cache_value(self, key: str) -> None:
+        """Used internally by the accessor properties."""
+        if key in self:
+            del self[key]
+
+    def to_header(self) -> str:
+        """Convert the stored values into a cache control header."""
+        return http.dump_header(self)
+
+    def __str__(self) -> str:
+        return self.to_header()
+
+    def __repr__(self) -> str:
+        kv_str = " ".join(f"{k}={v!r}" for k, v in sorted(self.items()))
+        return f"<{type(self).__name__} {kv_str}>"
+
+    cache_property = staticmethod(cache_control_property)
+
+
+class RequestCacheControl(ImmutableDictMixin[str, t.Optional[str]], _CacheControl):  # type: ignore[misc]
+    """A cache control for requests.  This is immutable and gives access
+    to all the request-relevant cache control headers.
+
+    To get a header of the :class:`RequestCacheControl` object again you can
+    convert the object into a string or call the :meth:`to_header` method.  If
+    you plan to subclass it and add your own items have a look at the sourcecode
+    for that class.
+
+    .. versionchanged:: 3.1
+        Dict values are always ``str | None``. Setting properties will
+        convert the value to a string. Setting a non-bool property to
+        ``False`` is equivalent to setting it to ``None``. Getting typed
+        properties will return ``None`` if conversion raises
+        ``ValueError``, rather than the string.
+
+    .. versionchanged:: 3.1
+       ``max_age`` is ``None`` if present without a value, rather
+       than ``-1``.
+
+    .. versionchanged:: 3.1
+        ``no_cache`` is a boolean, it is ``True`` instead of ``"*"``
+        when present.
+
+    .. versionchanged:: 3.1
+        ``max_stale`` is ``True`` if present without a value, rather
+        than ``"*"``.
+
+    .. versionchanged:: 3.1
+       ``no_transform`` is a boolean. Previously it was mistakenly
+       always ``None``.
+
+    .. versionchanged:: 3.1
+       ``min_fresh`` is ``None`` if present without a value, rather
+       than ``"*"``.
+
+    .. versionchanged:: 2.1
+        Setting int properties such as ``max_age`` will convert the
+        value to an int.
+
+    .. versionadded:: 0.5
+        Response-only properties are not present on this request class.
+    """
+
+    no_cache: bool = cache_control_property("no-cache", None, bool)
+    max_stale: int | t.Literal[True] | None = cache_control_property(
+        "max-stale",
+        True,
+        int,
+    )
+    min_fresh: int | None = cache_control_property("min-fresh", None, int)
+    only_if_cached: bool = cache_control_property("only-if-cached", None, bool)
+
+
+class ResponseCacheControl(_CacheControl):
+    """A cache control for responses.  Unlike :class:`RequestCacheControl`
+    this is mutable and gives access to response-relevant cache control
+    headers.
+
+    To get a header of the :class:`ResponseCacheControl` object again you can
+    convert the object into a string or call the :meth:`to_header` method.  If
+    you plan to subclass it and add your own items have a look at the sourcecode
+    for that class.
+
+    .. versionchanged:: 3.1
+        Dict values are always ``str | None``. Setting properties will
+        convert the value to a string. Setting a non-bool property to
+        ``False`` is equivalent to setting it to ``None``. Getting typed
+        properties will return ``None`` if conversion raises
+        ``ValueError``, rather than the string.
+
+    .. versionchanged:: 3.1
+        ``no_cache`` is ``True`` if present without a value, rather than
+        ``"*"``.
+
+    .. versionchanged:: 3.1
+        ``private`` is ``True`` if present without a value, rather than
+        ``"*"``.
+
+    .. versionchanged:: 3.1
+       ``no_transform`` is a boolean. Previously it was mistakenly
+       always ``None``.
+
+    .. versionchanged:: 3.1
+        Added the ``must_understand``, ``stale_while_revalidate``, and
+        ``stale_if_error`` properties.
+
+    .. versionchanged:: 2.1.1
+        ``s_maxage`` converts the value to an int.
+
+    .. versionchanged:: 2.1
+        Setting int properties such as ``max_age`` will convert the
+        value to an int.
+
+    .. versionadded:: 0.5
+       Request-only properties are not present on this response class.
+    """
+
+    no_cache: str | t.Literal[True] | None = cache_control_property(
+        "no-cache", True, None
+    )
+    public: bool = cache_control_property("public", None, bool)
+    private: str | t.Literal[True] | None = cache_control_property(
+        "private", True, None
+    )
+    must_revalidate: bool = cache_control_property("must-revalidate", None, bool)
+    proxy_revalidate: bool = cache_control_property("proxy-revalidate", None, bool)
+    s_maxage: int | None = cache_control_property("s-maxage", None, int)
+    immutable: bool = cache_control_property("immutable", None, bool)
+    must_understand: bool = cache_control_property("must-understand", None, bool)
+    stale_while_revalidate: int | None = cache_control_property(
+        "stale-while-revalidate", None, int
+    )
+
+
+# circular dependencies
+from .. import http