# 21.23. `http.cookies` — HTTP状态管理

源代码: 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`).

3.3 版更變: Allowed 『:』 as a valid Cookie name character.

備註

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()` to be the identity and `str()` respectively.

也參考

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 对象

`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 `Morsel`s. If it is a dictionary, it is equivalent to:

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

## 21.23.2. Morsel 对象

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 `''`.

  3.5 版更變: `__eq__()` now takes `key` and `value` into account.

`Morsel.``value`

  Cookie的值。

  3.5 版後已棄用: assigning to `value`; use `set()` instead.

`Morsel.``coded_value`

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

  3.5 版後已棄用: assigning to `coded_value`; use `set()` instead.

`Morsel.``key`

  The name of the cookie.

  3.5 版後已棄用: assigning to `key`; use `set()` instead.

`Morsel.``set`(key, value, coded_value)

  Set the key, value and coded_value attributes.

  3.5 版後已棄用: 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.

  3.5 版更變: an error is raised for invalid keys.

`Morsel.``copy`(value)

  Return a shallow copy of the Morsel object.

  3.5 版更變: 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. 示例

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