175 lines
5.9 KiB
Python
175 lines
5.9 KiB
Python
from __future__ import annotations
|
|
|
|
from .mixins import ImmutableDictMixin
|
|
from .mixins import UpdateDictMixin
|
|
|
|
|
|
def cache_control_property(key, empty, type):
|
|
"""Return a new property object for a cache header. Useful if you
|
|
want to add support for a cache extension in a subclass.
|
|
|
|
.. versionchanged:: 2.0
|
|
Renamed from ``cache_property``.
|
|
"""
|
|
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),
|
|
f"accessor for {key!r}",
|
|
)
|
|
|
|
|
|
class _CacheControl(UpdateDictMixin, dict):
|
|
"""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:: 2.1.0
|
|
Setting int properties such as ``max_age`` will convert the
|
|
value to an int.
|
|
|
|
.. versionchanged:: 0.4
|
|
|
|
Setting `no_cache` or `private` to boolean `True` will set the implicit
|
|
none-value which is ``*``:
|
|
|
|
>>> cc = ResponseCacheControl()
|
|
>>> cc.no_cache = True
|
|
>>> cc
|
|
<ResponseCacheControl 'no-cache'>
|
|
>>> cc.no_cache
|
|
'*'
|
|
>>> cc.no_cache = None
|
|
>>> cc
|
|
<ResponseCacheControl ''>
|
|
|
|
In versions before 0.5 the behavior documented here affected the now
|
|
no longer existing `CacheControl` class.
|
|
"""
|
|
|
|
no_cache = cache_control_property("no-cache", "*", None)
|
|
no_store = cache_control_property("no-store", None, bool)
|
|
max_age = cache_control_property("max-age", -1, int)
|
|
no_transform = cache_control_property("no-transform", None, None)
|
|
|
|
def __init__(self, values=(), on_update=None):
|
|
dict.__init__(self, values or ())
|
|
self.on_update = on_update
|
|
self.provided = values is not None
|
|
|
|
def _get_cache_value(self, key, empty, type):
|
|
"""Used internally by the accessor properties."""
|
|
if type is bool:
|
|
return key in self
|
|
if key in self:
|
|
value = self[key]
|
|
if value is None:
|
|
return empty
|
|
elif type is not None:
|
|
try:
|
|
value = type(value)
|
|
except ValueError:
|
|
pass
|
|
return value
|
|
return None
|
|
|
|
def _set_cache_value(self, key, value, type):
|
|
"""Used internally by the accessor properties."""
|
|
if type is bool:
|
|
if value:
|
|
self[key] = None
|
|
else:
|
|
self.pop(key, None)
|
|
else:
|
|
if value is None:
|
|
self.pop(key, None)
|
|
elif value is True:
|
|
self[key] = None
|
|
else:
|
|
if type is not None:
|
|
self[key] = type(value)
|
|
else:
|
|
self[key] = value
|
|
|
|
def _del_cache_value(self, key):
|
|
"""Used internally by the accessor properties."""
|
|
if key in self:
|
|
del self[key]
|
|
|
|
def to_header(self):
|
|
"""Convert the stored values into a cache control header."""
|
|
return http.dump_header(self)
|
|
|
|
def __str__(self):
|
|
return self.to_header()
|
|
|
|
def __repr__(self):
|
|
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, _CacheControl):
|
|
"""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:: 2.1.0
|
|
Setting int properties such as ``max_age`` will convert the
|
|
value to an int.
|
|
|
|
.. versionadded:: 0.5
|
|
In previous versions a `CacheControl` class existed that was used
|
|
both for request and response.
|
|
"""
|
|
|
|
max_stale = cache_control_property("max-stale", "*", int)
|
|
min_fresh = cache_control_property("min-fresh", "*", int)
|
|
only_if_cached = 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:: 2.1.1
|
|
``s_maxage`` converts the value to an int.
|
|
|
|
.. versionchanged:: 2.1.0
|
|
Setting int properties such as ``max_age`` will convert the
|
|
value to an int.
|
|
|
|
.. versionadded:: 0.5
|
|
In previous versions a `CacheControl` class existed that was used
|
|
both for request and response.
|
|
"""
|
|
|
|
public = cache_control_property("public", None, bool)
|
|
private = cache_control_property("private", "*", None)
|
|
must_revalidate = cache_control_property("must-revalidate", None, bool)
|
|
proxy_revalidate = cache_control_property("proxy-revalidate", None, bool)
|
|
s_maxage = cache_control_property("s-maxage", None, int)
|
|
immutable = cache_control_property("immutable", None, bool)
|
|
|
|
|
|
# circular dependencies
|
|
from .. import http
|