Cookie — HTTP state management
Note
The Cookie module has been renamed to http.cookies in Python
3.0. The 2to3 tool will automatically adapt imports when converting
your sources to 3.0.
The Cookie 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. As a
result, the parsing rules used are a bit less strict.
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.
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exception Cookie.CookieError
- Exception failing because of RFC 2109 invalidity: incorrect attributes,
incorrect Set-Cookie header, etc.
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class Cookie.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.
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class Cookie.SimpleCookie([input])
- This class derives from BaseCookie and overrides value_decode()
and value_encode() to be the identity and str() respectively.
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class Cookie.SerialCookie([input])
This class derives from BaseCookie and overrides value_decode()
and value_encode() to be the pickle.loads() and
pickle.dumps().
Deprecated since version 2.3: Reading pickled values from untrusted cookie data is a huge security hole, as
pickle strings can be crafted to cause arbitrary code to execute on your server.
It is supported for backwards compatibility only, and may eventually go away.
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class Cookie.SmartCookie([input])
This class derives from BaseCookie. It overrides value_decode()
to be pickle.loads() if it is a valid pickle, and otherwise the value
itself. It overrides value_encode() to be pickle.dumps() unless it
is a string, in which case it returns the value itself.
Deprecated since version 2.3: The same security warning from SerialCookie applies here.
A further security note is warranted. For backwards compatibility, the
Cookie module exports a class named Cookie which is just an
alias for SmartCookie. This is probably a mistake and will likely be
removed in a future version. You should not use the Cookie class in
your applications, for the same reason why you should not use the
SerialCookie class.
See also
- Module cookielib
- HTTP cookie handling for web clients. The cookielib and Cookie
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 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.
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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.
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BaseCookie.output([attrs[, header[, sep]]])
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).
Changed in version 2.5: The default separator has been changed from '\n' to match the cookie
specification.
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BaseCookie.js_output([attrs])
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
Morsel Objects
-
class Cookie.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 transfered
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.
New in version 2.6: The httponly attribute was added.
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Morsel.value
- The value of the cookie.
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Morsel.coded_value
- The encoded value of the cookie — this is what should be sent.
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Morsel.key
- The name of the cookie.
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Morsel.set(key, value, coded_value)
- Set the key, value and coded_value members.
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Morsel.isReservedKey(K)
- Whether K is a member of the set of keys of a Morsel.
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Morsel.output([attrs[, header]])
- 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:".
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Morsel.js_output([attrs])
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])
Return a string representing the Morsel, without any surrounding HTTP or
JavaScript.
The meaning for attrs is the same as in output().
Example
The following example demonstrates how to use the Cookie module.
>>> import Cookie
>>> C = Cookie.SimpleCookie()
>>> C = Cookie.SerialCookie()
>>> C = Cookie.SmartCookie()
>>> 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 = Cookie.SmartCookie()
>>> 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 = Cookie.SmartCookie()
>>> C.load("chips=ahoy; vienna=finger") # load from a string (HTTP header)
>>> print C
Set-Cookie: chips=ahoy
Set-Cookie: vienna=finger
>>> C = Cookie.SmartCookie()
>>> C.load('keebler="E=everybody; L=\\"Loves\\"; fudge=\\012;";')
>>> print C
Set-Cookie: keebler="E=everybody; L=\"Loves\"; fudge=\012;"
>>> C = Cookie.SmartCookie()
>>> C["oreo"] = "doublestuff"
>>> C["oreo"]["path"] = "/"
>>> print C
Set-Cookie: oreo=doublestuff; Path=/
>>> C = Cookie.SmartCookie()
>>> C["twix"] = "none for you"
>>> C["twix"].value
'none for you'
>>> C = Cookie.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
>>> C = Cookie.SerialCookie()
>>> C["number"] = 7
>>> C["string"] = "seven"
>>> C["number"].value
7
>>> C["string"].value
'seven'
>>> print C
Set-Cookie: number="I7\012."
Set-Cookie: string="S'seven'\012p1\012."
>>> C = Cookie.SmartCookie()
>>> C["number"] = 7
>>> C["string"] = "seven"
>>> C["number"].value
7
>>> C["string"].value
'seven'
>>> print C
Set-Cookie: number="I7\012."
Set-Cookie: string=seven
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