:mod:http.cookies --- HTTP state management

.. module:: http.cookies :synopsis: Support for HTTP state management (cookies).

.. moduleauthor:: Timothy O'Malley [email protected] .. sectionauthor:: Moshe Zadka [email protected]

Source code: :source:Lib/http/cookies.py

The :mod: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 doesn't follow the character rules outlined in those specs and also many current day browsers and servers have relaxed parsing rules when comes to Cookie handling. As a result, the parsing rules used are a bit less strict.

The character set, :data:string.ascii_letters, :data:string.digits and !#$%&'*+-.^_`|~: denote the set of valid characters allowed by this module in Cookie name (as :attr:~Morsel.key).

.. versionchanged:: 3.3 Allowed ':' as a valid Cookie name character.

.. note::

On encountering an invalid cookie, :exc:CookieError is raised, so if your cookie data comes from a browser you should always prepare for invalid data and catch :exc:CookieError on parsing.

.. exception:: CookieError

Exception failing because of :rfc:2109 invalidity: incorrect attributes, incorrect :mailheader:Set-Cookie header, etc.

.. class:: BaseCookie([input])

This class is a dictionary-like object whose keys are strings and whose values are :class:Morsel instances. Note that upon setting a key to a value, the value is first converted to a :class:Morsel containing the key and the value.

If input is given, it is passed to the :meth:load method.

.. class:: SimpleCookie([input])

This class derives from :class:BaseCookie and overrides :meth:value_decode and :meth:value_encode to be the identity and :func:str respectively.

.. seealso::

Module :mod:http.cookiejar HTTP cookie handling for web clients. The :mod:http.cookiejar and :mod:http.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:

Cookie Objects

.. method:: BaseCookie.value_decode(val)

Return a decoded value from a string representation. Return value can be any type. This method does nothing in :class:BaseCookie --- it exists so it can be overridden.

.. method:: BaseCookie.value_encode(val)

Return an encoded value. val can be any type, but return value must be a string. This method does nothing in :class:BaseCookie --- it exists so it can be overridden.

In general, it should be the case that :meth:value_encode and :meth:value_decode are inverses on the range of value_decode.

.. method:: 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 :class:Morsel's :meth:output method. sep is used to join the headers together, and is by default the combination '\r\n' (CRLF).

.. method:: BaseCookie.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 headers was sent.

The meaning for attrs is the same as in :meth:output.

.. method:: BaseCookie.load(rawdata)

If rawdata is a string, parse it as an HTTP_COOKIE and add the values found there as :class:Morsel\ s. If it is a dictionary, it is equivalent to::

  for k, v in rawdata.items():
      cookie[k] = v

.. _morsel-objects:

Morsel Objects

.. class:: 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

• expires
• path
• comment
• domain
• max-age
• secure
• version
• httponly

The attribute :attr: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 keys are case-insensitive and their default value is ''.

.. versionchanged:: 3.5 :meth:~Morsel.__eq__ now takes :attr:~Morsel.key and :attr:~Morsel.value into account.

.. versionchanged:: 3.7 Attributes :attr:~Morsel.key, :attr:~Morsel.value and :attr:~Morsel.coded_value are read-only. Use :meth:~Morsel.set for setting them.

.. attribute:: Morsel.value

The value of the cookie.

.. attribute:: Morsel.coded_value

The encoded value of the cookie --- this is what should be sent.

.. attribute:: Morsel.key

The name of the cookie.

.. method:: Morsel.set(key, value, coded_value)

Set the key, value and coded_value attributes.

.. method:: Morsel.isReservedKey(K)

Whether K is a member of the set of keys of a :class:Morsel.

.. method:: 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:".

.. method:: 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 :meth:output.

.. method:: 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 :meth:output.

.. method:: 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.

.. versionchanged:: 3.5 an error is raised for invalid keys.

.. method:: Morsel.copy(value)

Return a shallow copy of the Morsel object.

.. versionchanged:: 3.5 return a Morsel object instead of a dict.

.. method:: Morsel.setdefault(key, value=None)

Raise an error if key is not a valid :rfc:2109 attribute, otherwise behave the same as :meth:dict.setdefault.

.. _cookie-example:

Example

The following example demonstrates how to use the :mod:http.cookies module.

.. doctest:: :options: +NORMALIZE_WHITESPACE

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