# `http.cookiejar` —— HTTP 客户端的 Cookie 处理

源代码： Lib/http/cookiejar.py

`http.cookiejar` 模块定义了用于自动处理 HTTP cookie 的类。这对访问需要小段数据 —— cookies 的网站很有用，这些数据由 Web 服务器的 HTTP 响应在客户端计算机上设置，然后在以后的 HTTP 请求中返回给服务器。

常规的 Netscape Cookie 协议和 RFC 2965 定义的协议都可以处理。RFC 2965 处理默认情况下处于关闭状态。 RFC 2109 cookie 被解析为 Netscape cookie，随后根据有效的 'policy' 被视为 Netscape 或 RFC 2965 cookie。 请注意，Internet 上的大多数 cookie 是 Netscape cookie。 `http.cookiejar` 尝试遵循事实上的 Netscape cookie 协议（与原始 Netscape 规范中所设定的协议大不相同），包括注意 `max-age` 和 `port` RFC 2965 引入的 cookie 属性。

備註

在 Set-Cookie 和 Set-Cookie2 头中找到的各种命名参数通常指 attributes。为了不与 Python 属性相混淆，模块文档使用 cookie-attribute 代替。

此模块定义了以下异常：

exception `http.cookiejar.``LoadError`

  `FileCookieJar` 实例在从文件加载 cookies 出错时抛出这个异常。 `LoadError` 是 `OSError` 的一个子类。

  3.3 版更變: LoadError 成为 `OSError` 的子类而不是 `IOError`。

提供了以下类：

class `http.cookiejar.``CookieJar`(policy=None)

  policy 是实现了 `CookiePolicy` 接口的一个对象。

  `CookieJar` 类储存 HTTP cookies。它从 HTTP 请求提取 cookies，并在 HTTP 响应中返回它们。 `CookieJar` 实例在必要时自动处理包含 cookie 的到期情况。子类还负责储存和从文件或数据库中查找 cookies。

class `http.cookiejar.``FileCookieJar`(filename, delayload=None, policy=None)

  policy 是实现了 `CookiePolicy` 接口的一个对象。对于其他参数，参考相应属性的文档。

  一个可以从硬盘中文件加载或保存 cookie 的 `CookieJar`。 Cookies 不 会在 `load()` 或 `revert()` 方法调用前从命名的文件中加载。子类的文档位于段落 FileCookieJar subclasses and co-operation with web browsers。

  3.8 版更變: 文件名形参支持 path-like object。

class `http.cookiejar.``CookiePolicy`

  此类负责确定是否应从服务器接受每个 cookie 或将其返回给服务器。

class `http.cookiejar.``DefaultCookiePolicy`(blocked_domains=None, allowed_domains=None, netscape=True, rfc2965=False, rfc2109_as_netscape=None, hide_cookie2=False, strict_domain=False, strict_rfc2965_unverifiable=True, strict_ns_unverifiable=False, strict_ns_domain=DefaultCookiePolicy.DomainLiberal, strict_ns_set_initial_dollar=False, strict_ns_set_path=False, secure_protocols=("https", "wss"))

  构造参数只能以关键字参数传递，blocked_domains 是一个我们既不会接受也不会返回 cookie 的域名序列。allowed_domains 如果不是 `None`，则是仅有的我们会接受或返回的域名序列。secure_protocols 是可以添加安全 cookies 的协议序列。默认将 https 和 wss （安全 WebSocket）考虑为安全协议。对于其他参数，参考 `CookiePolicy` 和 `DefaultCookiePolicy` 对象的文档。

  `DefaultCookiePolicy` implements the standard accept / reject rules for Netscape and RFC 2965 cookies. By default, RFC 2109 cookies (ie. cookies received in a Set-Cookie header with a version cookie-attribute of 1) are treated according to the RFC 2965 rules. However, if RFC 2965 handling is turned off or `rfc2109_as_netscape` is `True`, RFC 2109 cookies are 'downgraded' by the `CookieJar` instance to Netscape cookies, by setting the `version` attribute of the `Cookie` instance to 0. `DefaultCookiePolicy` also provides some parameters to allow some fine-tuning of policy.

class `http.cookiejar.``Cookie`

  This class represents Netscape, RFC 2109 and RFC 2965 cookies. It is not expected that users of `http.cookiejar` construct their own `Cookie` instances. Instead, if necessary, call `make_cookies()` on a `CookieJar` instance.

也參考

Module `urllib.request`

  URL opening with automatic cookie handling.

Module `http.cookies`

  HTTP cookie classes, principally useful for server-side code. The `http.cookiejar` and `http.cookies` modules do not depend on each other.

https://curl.haxx.se/rfc/cookie_spec.html

  The specification of the original Netscape cookie protocol. Though this is still the dominant protocol, the 'Netscape cookie protocol' implemented by all the major browsers (and `http.cookiejar`) only bears a passing resemblance to the one sketched out in `cookie_spec.html`.

RFC 2109 - HTTP State Management Mechanism

  Obsoleted by RFC 2965. Uses Set-Cookie with version=1.

RFC 2965 - HTTP State Management Mechanism

  The Netscape protocol with the bugs fixed. Uses Set-Cookie2 in place of Set-Cookie. Not widely used.

http://kristol.org/cookie/errata.html

  Unfinished errata to RFC 2965.

RFC 2964 - Use of HTTP State Management

## CookieJar 和 FileCookieJar 对象

`CookieJar` objects support the iterator protocol for iterating over contained `Cookie` objects.

`CookieJar` has the following methods:

`CookieJar.``add_cookie_header`(request)

  Add correct Cookie header to request.

  If policy allows (ie. the `rfc2965` and `hide_cookie2` attributes of the `CookieJar`'s `CookiePolicy` instance are true and false respectively), the Cookie2 header is also added when appropriate.

  The request object (usually a `urllib.request.Request` instance) must support the methods `get_full_url()`, `get_host()`, `get_type()`, `unverifiable()`, `has_header()`, `get_header()`, `header_items()`, `add_unredirected_header()` and `origin_req_host` attribute as documented by `urllib.request`.

  3.3 版更變: request object needs `origin_req_host` attribute. Dependency on a deprecated method `get_origin_req_host()` has been removed.

`CookieJar.``extract_cookies`(response, request)

  Extract cookies from HTTP response and store them in the `CookieJar`, where allowed by policy.

  The `CookieJar` will look for allowable Set-Cookie and Set-Cookie2 headers in the response argument, and store cookies as appropriate (subject to the `CookiePolicy.set_ok()` method's approval).

  The response object (usually the result of a call to `urllib.request.urlopen()`, or similar) should support an `info()` method, which returns an `email.message.Message` instance.

  The request object (usually a `urllib.request.Request` instance) must support the methods `get_full_url()`, `get_host()`, `unverifiable()`, and `origin_req_host` attribute, as documented by `urllib.request`. The request is used to set default values for cookie-attributes as well as for checking that the cookie is allowed to be set.

  3.3 版更變: request object needs `origin_req_host` attribute. Dependency on a deprecated method `get_origin_req_host()` has been removed.

`CookieJar.``set_policy`(policy)

  Set the `CookiePolicy` instance to be used.

`CookieJar.``make_cookies`(response, request)

  Return sequence of `Cookie` objects extracted from response object.

  See the documentation for `extract_cookies()` for the interfaces required of the response and request arguments.

`CookieJar.``set_cookie_if_ok`(cookie, request)

  Set a `Cookie` if policy says it's OK to do so.

`CookieJar.``set_cookie`(cookie)

  Set a `Cookie`, without checking with policy to see whether or not it should be set.

`CookieJar.``clear`([domain[, path[, name]]])

  Clear some cookies.

  If invoked without arguments, clear all cookies. If given a single argument, only cookies belonging to that domain will be removed. If given two arguments, cookies belonging to the specified domain and URL path are removed. If given three arguments, then the cookie with the specified domain, path and name is removed.

  Raises `KeyError` if no matching cookie exists.

`CookieJar.``clear_session_cookies`()

  Discard all session cookies.

  Discards all contained cookies that have a true `discard` attribute (usually because they had either no `max-age` or `expires` cookie-attribute, or an explicit `discard` cookie-attribute). For interactive browsers, the end of a session usually corresponds to closing the browser window.

  Note that the `save()` method won't save session cookies anyway, unless you ask otherwise by passing a true ignore_discard argument.

`FileCookieJar` implements the following additional methods:

`FileCookieJar.``save`(filename=None, ignore_discard=False, ignore_expires=False)

  Save cookies to a file.

  This base class raises `NotImplementedError`. Subclasses may leave this method unimplemented.

  filename is the name of file in which to save cookies. If filename is not specified, `self.filename` is used (whose default is the value passed to the constructor, if any); if `self.filename` is `None`, `ValueError` is raised.

  ignore_discard: save even cookies set to be discarded. ignore_expires: save even cookies that have expired

  The file is overwritten if it already exists, thus wiping all the cookies it contains. Saved cookies can be restored later using the `load()` or `revert()` methods.

`FileCookieJar.``load`(filename=None, ignore_discard=False, ignore_expires=False)

  Load cookies from a file.

  Old cookies are kept unless overwritten by newly loaded ones.

  Arguments are as for `save()`.

  The named file must be in the format understood by the class, or `LoadError` will be raised. Also, `OSError` may be raised, for example if the file does not exist.

  3.3 版更變: 过去触发的 `IOError`，现在是 `OSError` 的别名。

`FileCookieJar.``revert`(filename=None, ignore_discard=False, ignore_expires=False)

  Clear all cookies and reload cookies from a saved file.

  `revert()` can raise the same exceptions as `load()`. If there is a failure, the object's state will not be altered.

`FileCookieJar` instances have the following public attributes:

`FileCookieJar.``filename`

  Filename of default file in which to keep cookies. This attribute may be assigned to.

`FileCookieJar.``delayload`

  If true, load cookies lazily from disk. This attribute should not be assigned to. This is only a hint, since this only affects performance, not behaviour (unless the cookies on disk are changing). A `CookieJar` object may ignore it. None of the `FileCookieJar` classes included in the standard library lazily loads cookies.

## FileCookieJar subclasses and co-operation with web browsers

The following `CookieJar` subclasses are provided for reading and writing.

class `http.cookiejar.``MozillaCookieJar`(filename, delayload=None, policy=None)

  A `FileCookieJar` that can load from and save cookies to disk in the Mozilla `cookies.txt` file format (which is also used by the Lynx and Netscape browsers).

  備註

  This loses information about RFC 2965 cookies, and also about newer or non-standard cookie-attributes such as `port`.

  警告

  Back up your cookies before saving if you have cookies whose loss / corruption would be inconvenient (there are some subtleties which may lead to slight changes in the file over a load / save round-trip).

  Also note that cookies saved while Mozilla is running will get clobbered by Mozilla.

class `http.cookiejar.``LWPCookieJar`(filename, delayload=None, policy=None)

  A `FileCookieJar` that can load from and save cookies to disk in format compatible with the libwww-perl library's `Set-Cookie3` file format. This is convenient if you want to store cookies in a human-readable file.

  3.8 版更變: 文件名形参支持 path-like object。

## CookiePolicy 对象

Objects implementing the `CookiePolicy` interface have the following methods:

`CookiePolicy.``set_ok`(cookie, request)

  Return boolean value indicating whether cookie should be accepted from server.

  cookie is a `Cookie` instance. request is an object implementing the interface defined by the documentation for `CookieJar.extract_cookies()`.

`CookiePolicy.``return_ok`(cookie, request)

  Return boolean value indicating whether cookie should be returned to server.

  cookie is a `Cookie` instance. request is an object implementing the interface defined by the documentation for `CookieJar.add_cookie_header()`.

`CookiePolicy.``domain_return_ok`(domain, request)

  Return `False` if cookies should not be returned, given cookie domain.

  This method is an optimization. It removes the need for checking every cookie with a particular domain (which might involve reading many files). Returning true from `domain_return_ok()` and `path_return_ok()` leaves all the work to `return_ok()`.

  If `domain_return_ok()` returns true for the cookie domain, `path_return_ok()` is called for the cookie path. Otherwise, `path_return_ok()` and `return_ok()` are never called for that cookie domain. If `path_return_ok()` returns true, `return_ok()` is called with the `Cookie` object itself for a full check. Otherwise, `return_ok()` is never called for that cookie path.

  Note that `domain_return_ok()` is called for every cookie domain, not just for the request domain. For example, the function might be called with both `".example.com"` and `"www.example.com"` if the request domain is `"www.example.com"`. The same goes for `path_return_ok()`.

  The request argument is as documented for `return_ok()`.

`CookiePolicy.``path_return_ok`(path, request)

  Return `False` if cookies should not be returned, given cookie path.

  See the documentation for `domain_return_ok()`.

In addition to implementing the methods above, implementations of the `CookiePolicy` interface must also supply the following attributes, indicating which protocols should be used, and how. All of these attributes may be assigned to.

`CookiePolicy.``netscape`

  Implement Netscape protocol.

`CookiePolicy.``rfc2965`

  Implement RFC 2965 protocol.

`CookiePolicy.``hide_cookie2`

  Don't add Cookie2 header to requests (the presence of this header indicates to the server that we understand RFC 2965 cookies).

The most useful way to define a `CookiePolicy` class is by subclassing from `DefaultCookiePolicy` and overriding some or all of the methods above. `CookiePolicy` itself may be used as a 'null policy' to allow setting and receiving any and all cookies (this is unlikely to be useful).

## DefaultCookiePolicy 对象

Implements the standard rules for accepting and returning cookies.

Both RFC 2965 and Netscape cookies are covered. RFC 2965 handling is switched off by default.

The easiest way to provide your own policy is to override this class and call its methods in your overridden implementations before adding your own additional checks:

    import http.cookiejar
    class MyCookiePolicy(http.cookiejar.DefaultCookiePolicy):
        def set_ok(self, cookie, request):
            if not http.cookiejar.DefaultCookiePolicy.set_ok(self, cookie, request):
                return False
            if i_dont_want_to_store_this_cookie(cookie):
                return False
            return True

In addition to the features required to implement the `CookiePolicy` interface, this class allows you to block and allow domains from setting and receiving cookies. There are also some strictness switches that allow you to tighten up the rather loose Netscape protocol rules a little bit (at the cost of blocking some benign cookies).

A domain blacklist and whitelist is provided (both off by default). Only domains not in the blacklist and present in the whitelist (if the whitelist is active) participate in cookie setting and returning. Use the blocked_domains constructor argument, and `blocked_domains()` and `set_blocked_domains()` methods (and the corresponding argument and methods for allowed_domains). If you set a whitelist, you can turn it off again by setting it to `None`.

Domains in block or allow lists that do not start with a dot must equal the cookie domain to be matched. For example, `"example.com"` matches a blacklist entry of `"example.com"`, but `"www.example.com"` does not. Domains that do start with a dot are matched by more specific domains too. For example, both `"www.example.com"` and `"www.coyote.example.com"` match `".example.com"` (but `"example.com"` itself does not). IP addresses are an exception, and must match exactly. For example, if blocked_domains contains `"192.168.1.2"` and `".168.1.2"`, 192.168.1.2 is blocked, but 193.168.1.2 is not.

`DefaultCookiePolicy` implements the following additional methods:

`DefaultCookiePolicy.``blocked_domains`()

  Return the sequence of blocked domains (as a tuple).

`DefaultCookiePolicy.``set_blocked_domains`(blocked_domains)

  Set the sequence of blocked domains.

`DefaultCookiePolicy.``is_blocked`(domain)

  Return whether domain is on the blacklist for setting or receiving cookies.

`DefaultCookiePolicy.``allowed_domains`()

  Return `None`, or the sequence of allowed domains (as a tuple).

`DefaultCookiePolicy.``set_allowed_domains`(allowed_domains)

  Set the sequence of allowed domains, or `None`.

`DefaultCookiePolicy.``is_not_allowed`(domain)

  Return whether domain is not on the whitelist for setting or receiving cookies.

`DefaultCookiePolicy` instances have the following attributes, which are all initialised from the constructor arguments of the same name, and which may all be assigned to.

`DefaultCookiePolicy.``rfc2109_as_netscape`

  If true, request that the `CookieJar` instance downgrade RFC 2109 cookies (ie. cookies received in a Set-Cookie header with a version cookie-attribute of 1) to Netscape cookies by setting the version attribute of the `Cookie` instance to 0. The default value is `None`, in which case RFC 2109 cookies are downgraded if and only if RFC 2965 handling is turned off. Therefore, RFC 2109 cookies are downgraded by default.

General strictness switches:

`DefaultCookiePolicy.``strict_domain`

  Don't allow sites to set two-component domains with country-code top-level domains like `.co.uk`, `.gov.uk`, `.co.nz`.etc. This is far from perfect and isn't guaranteed to work!

RFC 2965 protocol strictness switches:

`DefaultCookiePolicy.``strict_rfc2965_unverifiable`

  Follow RFC 2965 rules on unverifiable transactions (usually, an unverifiable transaction is one resulting from a redirect or a request for an image hosted on another site). If this is false, cookies are never blocked on the basis of verifiability

Netscape protocol strictness switches:

`DefaultCookiePolicy.``strict_ns_unverifiable`

  Apply RFC 2965 rules on unverifiable transactions even to Netscape cookies.

`DefaultCookiePolicy.``strict_ns_domain`

  Flags indicating how strict to be with domain-matching rules for Netscape cookies. See below for acceptable values.

`DefaultCookiePolicy.``strict_ns_set_initial_dollar`

  Ignore cookies in Set-Cookie: headers that have names starting with `'$'`.

`DefaultCookiePolicy.``strict_ns_set_path`

  Don't allow setting cookies whose path doesn't path-match request URI.

`strict_ns_domain` is a collection of flags. Its value is constructed by or-ing together (for example, `DomainStrictNoDots|DomainStrictNonDomain` means both flags are set).

`DefaultCookiePolicy.``DomainStrictNoDots`

  When setting cookies, the 'host prefix' must not contain a dot (eg. `www.foo.bar.com` can't set a cookie for `.bar.com`, because `www.foo` contains a dot).

`DefaultCookiePolicy.``DomainStrictNonDomain`

  Cookies that did not explicitly specify a `domain` cookie-attribute can only be returned to a domain equal to the domain that set the cookie (eg. `spam.example.com` won't be returned cookies from `example.com` that had no `domain` cookie-attribute).

`DefaultCookiePolicy.``DomainRFC2965Match`

  When setting cookies, require a full RFC 2965 domain-match.

The following attributes are provided for convenience, and are the most useful combinations of the above flags:

`DefaultCookiePolicy.``DomainLiberal`

  Equivalent to 0 (ie. all of the above Netscape domain strictness flags switched off).

`DefaultCookiePolicy.``DomainStrict`

  Equivalent to `DomainStrictNoDots|DomainStrictNonDomain`.

## Cookie 对象

`Cookie` instances have Python attributes roughly corresponding to the standard cookie-attributes specified in the various cookie standards. The correspondence is not one-to-one, because there are complicated rules for assigning default values, because the `max-age` and `expires` cookie-attributes contain equivalent information, and because RFC 2109 cookies may be 'downgraded' by `http.cookiejar` from version 1 to version 0 (Netscape) cookies.

Assignment to these attributes should not be necessary other than in rare circumstances in a `CookiePolicy` method. The class does not enforce internal consistency, so you should know what you're doing if you do that.

`Cookie.``version`

  Integer or `None`. Netscape cookies have `version` 0. RFC 2965 and RFC 2109 cookies have a `version` cookie-attribute of 1. However, note that `http.cookiejar` may 'downgrade' RFC 2109 cookies to Netscape cookies, in which case `version` is 0.

`Cookie.``name`

  Cookie name (a string).

`Cookie.``value`

  Cookie value (a string), or `None`.

`Cookie.``port`

  String representing a port or a set of ports (eg. '80', or '80,8080'), or `None`.

`Cookie.``path`

  Cookie path (a string, eg. `'/acme/rocket_launchers'`).

`Cookie.``secure`

  `True` if cookie should only be returned over a secure connection.

`Cookie.``expires`

  Integer expiry date in seconds since epoch, or `None`. See also the `is_expired()` method.

`Cookie.``discard`

  `True` if this is a session cookie.

`Cookie.``comment`

  String comment from the server explaining the function of this cookie, or `None`.

`Cookie.``comment_url`

  URL linking to a comment from the server explaining the function of this cookie, or `None`.

`Cookie.``rfc2109`

  `True` if this cookie was received as an RFC 2109 cookie (ie. the cookie arrived in a Set-Cookie header, and the value of the Version cookie-attribute in that header was 1). This attribute is provided because `http.cookiejar` may 'downgrade' RFC 2109 cookies to Netscape cookies, in which case `version` is 0.

`Cookie.``port_specified`

  `True` if a port or set of ports was explicitly specified by the server (in the Set-Cookie / Set-Cookie2 header).

`Cookie.``domain_specified`

  `True` if a domain was explicitly specified by the server.

`Cookie.``domain_initial_dot`

  `True` if the domain explicitly specified by the server began with a dot (`'.'`).

Cookies may have additional non-standard cookie-attributes. These may be accessed using the following methods:

`Cookie.``has_nonstandard_attr`(name)

  Return `True` if cookie has the named cookie-attribute.

`Cookie.``get_nonstandard_attr`(name, default=None)

  If cookie has the named cookie-attribute, return its value. Otherwise, return default.

`Cookie.``set_nonstandard_attr`(name, value)

  Set the value of the named cookie-attribute.

The `Cookie` class also defines the following method:

`Cookie.``is_expired`(now=None)

  `True` if cookie has passed the time at which the server requested it should expire. If now is given (in seconds since the epoch), return whether the cookie has expired at the specified time.

## 示例

The first example shows the most common usage of `http.cookiejar`:

    import http.cookiejar, urllib.request
    cj = http.cookiejar.CookieJar()
    opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
    r = opener.open("http://example.com/")

This example illustrates how to open a URL using your Netscape, Mozilla, or Lynx cookies (assumes Unix/Netscape convention for location of the cookies file):

    import os, http.cookiejar, urllib.request
    cj = http.cookiejar.MozillaCookieJar()
    cj.load(os.path.join(os.path.expanduser("~"), ".netscape", "cookies.txt"))
    opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
    r = opener.open("http://example.com/")

The next example illustrates the use of `DefaultCookiePolicy`. Turn on RFC 2965 cookies, be more strict about domains when setting and returning Netscape cookies, and block some domains from setting cookies or having them returned:

    import urllib.request
    from http.cookiejar import CookieJar, DefaultCookiePolicy
    policy = DefaultCookiePolicy(
        rfc2965=True, strict_ns_domain=Policy.DomainStrict,
        blocked_domains=["ads.net", ".ads.net"])
    cj = CookieJar(policy)
    opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
    r = opener.open("http://example.com/")