21.23. 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 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, string.ascii_letters, string.digits and
!#$%&'*+-.^_`|~: denote the set of valid characters allowed by this module
in Cookie name (as key).
Changed in version 3.3: Allowed ‘:’ as a valid Cookie name character.
Note
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 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 a Morsel 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 overrides value_decode()
and value_encode() to be the identity and str() respectively.
See also
- Module
http.cookiejar
- HTTP cookie handling for web clients. The
http.cookiejar and
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.
21.23.1. Cookie Objects
-
BaseCookie.value_decode(val)
Return a decoded value from a string representation. Return value can be any
type. This method does nothing in BaseCookie — it exists so it can be
overridden.
-
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 BaseCookie — it exists so it can
be overridden.
In general, it should be the case that value_encode() and
value_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’s output() method. sep is used
to join the headers together, and is by default the combination '\r\n'
(CRLF).
-
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 output().
-
BaseCookie.load(rawdata)
If rawdata is a string, parse it as an HTTP_COOKIE and add the values
found there as Morsels. If it is a dictionary, it is equivalent to:
for k, v in rawdata.items():
cookie[k] = v
21.23.2. 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
expires
path
comment
domain
max-age
secure
version
httponly
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 keys are case-insensitive and their default value is ''.
Changed in version 3.5: __eq__() now takes key and value
into account.
-
Morsel.value
The value of the cookie.
Deprecated since version 3.5: assigning to value; use set() instead.
-
Morsel.coded_value
The encoded value of the cookie — this is what should be sent.
Deprecated since version 3.5: assigning to coded_value; use set() instead.
-
Morsel.key
The name of the cookie.
Deprecated since version 3.5: assigning to key; use set() instead.
-
Morsel.set(key, value, coded_value)
Set the key, value and coded_value attributes.
Deprecated since version 3.5: The undocumented LegalChars parameter is ignored and will be removed in
a future version.
-
Morsel.isReservedKey(K)
Whether K is a member of the set of keys of a Morsel.
-
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.
Changed in version 3.5: an error is raised for invalid keys.
-
Morsel.copy(value)
Return a shallow copy of the Morsel object.
Changed in version 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().
21.23.3. 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