http.cookies
— HTTP state management¶
Source code: Lib/http/cookies.py
The http.cookies
module defines classes for abstracting the concept of
cookies, an HTTP state management mechanism. It supports both simple string-only
cookies, and provides an abstraction for having any serializable data-type as
cookie value.
The module formerly strictly applied the parsing rules described in the RFC 2109 and RFC 2068 specifications. It has since been discovered that MSIE 3.0x didn’t follow the character rules outlined in those specs; many current-day browsers and servers have also relaxed parsing rules when it comes to cookie handling. As a result, this module now uses parsing rules that are a bit less strict than they once were.
The character set, string.ascii_letters
, string.digits
and
!#$%&'*+-.^_`|~:
denote the set of valid characters allowed by this module
in a cookie name (as key
).
Zmienione w wersji 3.3: Allowed «:» as a valid cookie name character.
Informacja
On encountering an invalid cookie, CookieError
is raised, so if your
cookie data comes from a browser you should always prepare for invalid data
and catch CookieError
on parsing.
- exception http.cookies.CookieError¶
Exception failing because of RFC 2109 invalidity: incorrect attributes, incorrect Set-Cookie header, etc.
- class http.cookies.BaseCookie([input])¶
This class is a dictionary-like object whose keys are strings and whose values are
Morsel
instances. Note that upon setting a key to a value, the value is first converted to aMorsel
containing the key and the value.If input is given, it is passed to the
load()
method.
- class http.cookies.SimpleCookie([input])¶
This class derives from
BaseCookie
and overridesvalue_decode()
andvalue_encode()
.SimpleCookie
supports strings as cookie values. When setting the value,SimpleCookie
calls the builtinstr()
to convert the value to a string. Values received from HTTP are kept as strings.
Zobacz także
- Module
http.cookiejar
HTTP cookie handling for web clients. The
http.cookiejar
andhttp.cookies
modules do not depend on each other.- RFC 2109 - HTTP State Management Mechanism
This is the state management specification implemented by this module.
Cookie Objects¶
- BaseCookie.value_decode(val)¶
Return a tuple
(real_value, coded_value)
from a string representation.real_value
can be any type. This method does no decoding inBaseCookie
— it exists so it can be overridden.
- BaseCookie.value_encode(val)¶
Return a tuple
(real_value, coded_value)
. val can be any type, butcoded_value
will always be converted to a string. This method does no encoding inBaseCookie
— it exists so it can be overridden.In general, it should be the case that
value_encode()
andvalue_decode()
are inverses on the range of value_decode.
- BaseCookie.output(attrs=None, header='Set-Cookie:', sep='\r\n')¶
Return a string representation suitable to be sent as HTTP headers. attrs and header are sent to each
Morsel
’soutput()
method. sep is used to join the headers together, and is by default the combination'\r\n'
(CRLF).
Morsel Objects¶
- class http.cookies.Morsel¶
Abstract a key/value pair, which has some RFC 2109 attributes.
Morsels are dictionary-like objects, whose set of keys is constant — the valid RFC 2109 attributes, which are:
The attribute
httponly
specifies that the cookie is only transferred in HTTP requests, and is not accessible through JavaScript. This is intended to mitigate some forms of cross-site scripting.The attribute
samesite
specifies that the browser is not allowed to send the cookie along with cross-site requests. This helps to mitigate CSRF attacks. Valid values for this attribute are „Strict” and „Lax”.The keys are case-insensitive and their default value is
''
.Zmienione w wersji 3.7: Attributes
key
,value
andcoded_value
are read-only. Useset()
for setting them.Zmienione w wersji 3.8: Added support for the
samesite
attribute.
- Morsel.value¶
The value of the cookie.
- Morsel.coded_value¶
The encoded value of the cookie — this is what should be sent.
- Morsel.key¶
The name of the cookie.
- Morsel.set(key, value, coded_value)¶
Set the key, value and coded_value attributes.
- Morsel.output(attrs=None, header='Set-Cookie:')¶
Return a string representation of the Morsel, suitable to be sent as an HTTP header. By default, all the attributes are included, unless attrs is given, in which case it should be a list of attributes to use. header is by default
"Set-Cookie:"
.
- Morsel.js_output(attrs=None)¶
Return an embeddable JavaScript snippet, which, if run on a browser which supports JavaScript, will act the same as if the HTTP header was sent.
The meaning for attrs is the same as in
output()
.
- Morsel.OutputString(attrs=None)¶
Return a string representing the Morsel, without any surrounding HTTP or JavaScript.
The meaning for attrs is the same as in
output()
.
- Morsel.update(values)¶
Update the values in the Morsel dictionary with the values in the dictionary values. Raise an error if any of the keys in the values dict is not a valid RFC 2109 attribute.
Zmienione w wersji 3.5: an error is raised for invalid keys.
- Morsel.copy(value)¶
Return a shallow copy of the Morsel object.
Zmienione w wersji 3.5: return a Morsel object instead of a dict.
- Morsel.setdefault(key, value=None)¶
Raise an error if key is not a valid RFC 2109 attribute, otherwise behave the same as
dict.setdefault()
.
Example¶
The following example demonstrates how to use the http.cookies
module.
>>> from http import cookies
>>> C = cookies.SimpleCookie()
>>> C["fig"] = "newton"
>>> C["sugar"] = "wafer"
>>> print(C) # generate HTTP headers
Set-Cookie: fig=newton
Set-Cookie: sugar=wafer
>>> print(C.output()) # same thing
Set-Cookie: fig=newton
Set-Cookie: sugar=wafer
>>> C = cookies.SimpleCookie()
>>> C["rocky"] = "road"
>>> C["rocky"]["path"] = "/cookie"
>>> print(C.output(header="Cookie:"))
Cookie: rocky=road; Path=/cookie
>>> print(C.output(attrs=[], header="Cookie:"))
Cookie: rocky=road
>>> C = cookies.SimpleCookie()
>>> C.load("chips=ahoy; vienna=finger") # load from a string (HTTP header)
>>> print(C)
Set-Cookie: chips=ahoy
Set-Cookie: vienna=finger
>>> C = cookies.SimpleCookie()
>>> C.load('keebler="E=everybody; L=\\"Loves\\"; fudge=\\012;";')
>>> print(C)
Set-Cookie: keebler="E=everybody; L=\"Loves\"; fudge=\012;"
>>> C = cookies.SimpleCookie()
>>> C["oreo"] = "doublestuff"
>>> C["oreo"]["path"] = "/"
>>> print(C)
Set-Cookie: oreo=doublestuff; Path=/
>>> C = cookies.SimpleCookie()
>>> C["twix"] = "none for you"
>>> C["twix"].value
'none for you'
>>> C = cookies.SimpleCookie()
>>> C["number"] = 7 # equivalent to C["number"] = str(7)
>>> C["string"] = "seven"
>>> C["number"].value
'7'
>>> C["string"].value
'seven'
>>> print(C)
Set-Cookie: number=7
Set-Cookie: string=seven