http.cookies — HTTP state management - Python 3.11.1 documentation 编辑

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 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 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(). SimpleCookie supports strings as cookie values. When setting the value, SimpleCookie calls the builtin str() to convert the value to a string. Values received from HTTP are kept as strings.

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.

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 in BaseCookie — it exists so it can be overridden.

BaseCookie.value_encode(val)

Return a tuple (real_value, coded_value). val can be any type, but coded_value will always be converted to a string. This method does no encoding 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

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

• samesite

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 ''.

Changed in version 3.5: __eq__() now takes key and value into account.

Changed in version 3.7: Attributes key, value and coded_value are read-only. Use set() for setting them.

Changed in version 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.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().

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