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 协议和由 RFC 2965 定义的协议都可以被处理。 RFC 2965 的处理默认是关闭的。 RFC 2109 cookie 被解析为 Netscape cookie ，随后根据当前使用的 "策略"，被视为 Netscape 或 RFC 2965 cookie。http.cookiejar 试图遵循事实上的 Netscape cookie 协议（它与原始Netscape规范中的协议有很大不同），包括注意到 RFC 2965 中引入的``max-age``和``port``cookie 属性。

注解

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。

在 3.3 版更改: 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。

在 3.8 版更改: 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 实现了 Netscape 和 RFC 2965 cookies 的标准接受 / 拒绝规则。 默认情况下，RFC 2109 cookies（即在 Set-Cookie 头中收到的 cookie-attribute 版本为 1 的 cookies ）将按照 RFC 2965 规则处理。 然而，如果 RFC 2965 的处理被关闭，或者 rfc2109_as_netscape 为 True，Cookie 实例的 version 属性设置将被为 0， RFC 2109 cookies CookieJar 实例将 "降级" 为 Netscape cookies。 DefaultCookiePolicy 也提供一些参数以允许一些策略微调。

class http.cookiejar.Cookie

这个类代表 Netscape、RFC 2109 和 RFC 2965 的 cookie 。 我们不希望 http.cookiejar 的用户构建他们自己的 Cookie 实例。 如果有必要，请在一个 CookieJar 实例上调用 make_cookies() 。

参见

模块 urllib.request

URL 打开带有自动的 cookie 处理。

模块 http.cookies

HTTP cookie类，主要是对服务端代码有用。 http.cookiejar 和 http.cookies 模块不相互依赖。

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

原始 Netscape cookie 协议的规范。 虽然这仍然是主流协议，但所有主要浏览器（以及 http.cookiejar ）实现的 "Netscape cookie协议" 与``cookie_spec.html``中描述的协议仅有几分相似之处。

RFC 2109 - HTTP状态管理机制

被 RFC 2965 所取代。使用 Set-Cookie version=1 。

RFC 2965 - HTTP状态管理机制

修正了错误的 Netscape 协议。 使用 Set-Cookie2 来代替 Set-Cookie 。 没有广泛被使用。

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

未完成的:rfc:2965 勘误表。

RFC 2964 - HTTP状态管理使用方法

CookieJar 和 FileCookieJar 对象

CookieJar 对象支持 iterator 协议，用于迭代包含的 Cookie 对象。

CookieJar 有以下方法：

在 request 中添加正确的 Cookie 头。

如果策略允许（即 rfc2965 和 hide_cookie2 属性在 CookieJar 的 CookiePolicy 实例中分别为 True 和 False ）， Cookie2 标头也会在适当时候添加。

如 urllib.request 所记载的， request 对象（通常是一个 urllib.request.Request 实例）必须支持 get_full_url() , get_host(), get_type(), unverifiable(), has_header(), get_header(), header_items(), add_unredirected_header() 和 origin_req_host 属性。

在 3.3 版更改: request 对象需要 origin_req_host 属性。对已废弃的方法 get_origin_req_host() 的依赖已被移除。

CookieJar.extract_cookies(response, request)

从HTTP response 中提取 cookie，并在政策允许的情况下，将它们存储在 CookieJar 中。

CookieJar 将 在*response* 参数中寻找允许的 Set-Cookie 和 Set-Cookie2 头信息，并适当地存储cookies（须经 CookiePolicy.set_ok() 方法批准）。

response 对象（通常是调用 urllib.request.urlopen() 或类似方法的结果）应该支持 info() 方法，它返回 email.message.Message 实例。

如 urllib.request 的文档所说，request 对象（通常是一个 urllib.request.Request 实例）必须支持 get_full_url(), get_host(), unverifiable() 和 origin_req_host 属性。 该请求用于设置 cookie-attributes 的默认值，以及检查 cookie 是否允许被设置。

在 3.3 版更改: request 对象需要 origin_req_host 属性。对已废弃的方法 get_origin_req_host() 的依赖已被移除。

CookieJar.set_policy(policy)

设置要使用的 CookiePolicy 实例。

CookieJar.make_cookies(response, request)

返回从 response 对象中提取的 Cookie 对象的序列。

关于 response 和 request 参数所需的接口，请参见 extract_cookies() 的文档。

如果策略规定可以这样做，就设置一个 Cookie 。

设置一个 Cookie，不需要检查策略是否应该被设置。

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

清除一些cookie。

如果调用时没有参数，则清除所有的cookie。 如果给定一个参数，只有属于该 domain 的cookies将被删除。如果给定两个参数，那么属于指定的 domain 和 URL path 的cookie将被删除。 如果给定三个参数，那么属于指定的 domain 、path 和 name 的cookie将被删除

如果不存在匹配的 cookie，则会引发 KeyError。

CookieJar.clear_session_cookies()

丢弃所有session cookie。

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.

在 3.3 版更改: 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).

注解

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.

在 3.8 版更改: 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 blocklist and allowlist is provided (both off by default). Only domains not in the blocklist and present in the allowlist (if the allowlist 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 an allowlist, 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 blocklist 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 blocklist 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 allowlist 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.

例子

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/")