http.cookiejar
— 用于 HTTP 客户端的 Cookie 处理
¶
The
http.cookiejar
module defines classes for automatic handling of HTTP cookies. It is useful for accessing web sites that require small pieces of data –
Cookie
– to be set on the client machine by an HTTP response from a web server, and then returned to the server in later HTTP requests.
Both the regular Netscape cookie protocol and the protocol defined by
RFC 2965
are handled. RFC 2965 handling is switched off by default.
RFC 2109
cookies are parsed as Netscape cookies and subsequently treated either as Netscape or RFC 2965 cookies according to the ‘policy’ in effect. Note that the great majority of cookies on the Internet are Netscape cookies.
http.cookiejar
attempts to follow the de-facto Netscape cookie protocol (which differs substantially from that set out in the original Netscape specification), including taking note of the
max-age
and
port
cookie-attributes introduced with RFC 2965.
注意
The various named parameters found in
Set-Cookie
and
Set-Cookie2
headers (eg.
domain
and
expires
) are conventionally referred to as
属性
. To distinguish them from Python attributes, the documentation for this module uses the term
cookie-attribute
代替。
模块定义以下异常:
实例化的
FileCookieJar
raise this exception on failure to load cookies from a file.
LoadError
是子类化的
OSError
.
3.3 版改变:
LoadError 是子类化的
OSError
而不是
IOError
.
提供了下列类:
policy
是对象实现
CookiePolicy
接口。
The
CookieJar
class stores HTTP cookies. It extracts cookies from HTTP requests, and returns them in HTTP responses.
CookieJar
instances automatically expire contained cookies when necessary. Subclasses are also responsible for storing and retrieving cookies from a file or database.
policy
是对象实现
CookiePolicy
interface. For the other arguments, see the documentation for the corresponding attributes.
A
CookieJar
which can load cookies from, and perhaps save cookies to, a file on disk. Cookies are
NOT
loaded from the named file until either the
load()
or
revert()
method is called. Subclasses of this class are documented in section
FileCookieJar 子类和与 Web 浏览器合作
.
3.8 版改变: 文件名参数支持 像路径对象 .
This class is responsible for deciding whether each cookie should be accepted from / returned to the server.
Constructor arguments should be passed as keyword arguments only.
blocked_domains
is a sequence of domain names that we never accept cookies from, nor return cookies to.
allowed_domains
if not
None
, this is a sequence of the only domains for which we accept and return cookies.
secure_protocols
is a sequence of protocols for which secure cookies can be added to. By default
https
and
wss
(secure websocket) are considered secure protocols. For all other arguments, see the documentation for
CookiePolicy
and
DefaultCookiePolicy
对象。
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
属性在
Cookie
instance to 0.
DefaultCookiePolicy
also provides some parameters to allow some fine-tuning of policy.
此类表示 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()
在
CookieJar
实例。
另请参阅
urllib.request
采用自动 Cookie 处理打开 URL。
http.cookies
HTTP cookie classes, principally useful for server-side code. The
http.cookiejar
and
http.cookies
模块不相互依赖。
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
.
Obsoleted by RFC 2965 . Uses Set-Cookie with version=1.
The Netscape protocol with the bugs fixed. Uses Set-Cookie2 in place of Set-Cookie . Not widely used.
Unfinished errata to RFC 2965 .
RFC 2964 - Use of HTTP State Management
CookieJar
objects support the
iterator
protocol for iterating over contained
Cookie
对象。
CookieJar
拥有下列方法:
添加正确 Cookie header to request .
若策略允许 (即
rfc2965
and
hide_cookie2
属性对于
CookieJar
’s
CookiePolicy
instance are true and false respectively), the
Cookie2
header is also added when appropriate.
The
request
对象 (通常
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 版改变:
request
对象需要
origin_req_host
attribute. Dependency on a deprecated method
get_origin_req_host()
已被移除。
提取 Cookie 从 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
实例。
The
request
对象 (通常
urllib.request.Request
instance) must support the methods
get_full_url()
,
get_host()
,
unverifiable()
,和
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 版改变:
request
对象需要
origin_req_host
attribute. Dependency on a deprecated method
get_origin_req_host()
已被移除。
设置
CookiePolicy
要使用的实例。
Return sequence of
Cookie
objects extracted from
response
对象。
见文档编制为
extract_cookies()
for the interfaces required of the
response
and
request
自变量。
设置
Cookie
if policy says it’s OK to do so.
设置
Cookie
, without checking with policy to see whether or not it should be set.
清零某些 Cookie。
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.
引发
KeyError
if no matching cookie exists.
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.
注意,
save()
method won’t save session cookies anyway, unless you ask otherwise by passing a true
ignore_discard
自变量。
FileCookieJar
实现下列额外方法:
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
未指定,
self.filename
is used (whose default is the value passed to the constructor, if any); if
self.filename
is
None
,
ValueError
被引发。
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()
方法。
加载 Cookie 从文件。
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.
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
实例拥有下列公共属性:
Filename of default file in which to keep cookies. This attribute may be assigned to.
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.
下列
CookieJar
子类的提供为读写。
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).
注意
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.
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 版改变: 文件名参数支持 像路径对象 .
对象实现
CookiePolicy
接口拥有下列方法:
Return boolean value indicating whether cookie should be accepted from server.
cookie
是
Cookie
实例。
request
is an object implementing the interface defined by the documentation for
CookieJar.extract_cookies()
.
Return boolean value indicating whether cookie should be returned to server.
cookie
是
Cookie
实例。
request
is an object implementing the interface defined by the documentation for
CookieJar.add_cookie_header()
.
返回
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()
.
若
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()
返回 True,
return_ok()
is called with the
Cookie
object itself for a full check. Otherwise,
return_ok()
is never called for that cookie path.
注意,
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()
.
返回
False
if cookies should not be returned, given cookie path.
见文档编制为
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.
实现 Netscape 协议。
实现 RFC 2965 协议。
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).
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"
,但
"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"
(但
"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
实现下列额外方法:
Return the sequence of blocked domains (as a tuple).
Set the sequence of blocked domains.
Return whether domain is on the blacklist for setting or receiving cookies.
返回
None
, or the sequence of allowed domains (as a tuple).
Set the sequence of allowed domains, or
None
.
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.
若 true,请求
CookieJar
实例降级
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.
一般严格开关:
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:
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:
应用 RFC 2965 rules on unverifiable transactions even to Netscape cookies.
Flags indicating how strict to be with domain-matching rules for Netscape cookies. See below for acceptable values.
Ignore cookies in Set-Cookie: headers that have names starting with
'$'
.
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).
When setting cookies, the ‘host prefix’ must not contain a dot (eg.
www.foo.bar.com
can’t set a cookie for
.bar.com
,因为
www.foo
contains a dot).
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).
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:
Equivalent to 0 (ie. all of the above Netscape domain strictness flags switched off).
相当于
DomainStrictNoDots|DomainStrictNonDomain
.
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.
整数或
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
为 0。
Cookie 名称 (字符串)。
Cookie 值 (字符串),或
None
.
String representing a port or a set of ports (eg. ‘80’, or ‘80,8080’), or
None
.
Cookie 路径 (字符串,如
'/acme/rocket_launchers'
).
True
if cookie should only be returned over a secure connection.
Integer expiry date in seconds since epoch, or
None
。另请参阅
is_expired()
方法。
True
若这是会话 Cookie。
String comment from the server explaining the function of this cookie, or
None
.
URL linking to a comment from the server explaining the function of this cookie, or
None
.
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
为 0。
True
if a port or set of ports was explicitly specified by the server (in the
Set-Cookie
/
Set-Cookie2
头)。
True
if a domain was explicitly specified by the server.
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:
返回
True
if cookie has the named cookie-attribute.
If cookie has the named cookie-attribute, return its value. Otherwise, return default .
Set the value of the named cookie-attribute.
The
Cookie
class also defines the following method:
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.
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/")