http.cookiejar
— Cookie handling for HTTP clients¶
Source code: Lib/http/cookiejar.py
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
– cookies – 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.
Примітка
The various named parameters found in Set-Cookie and
Set-Cookie2 headers (eg. domain
and expires
) are
conventionally referred to as attributes. To distinguish them from
Python attributes, the documentation for this module uses the term
cookie-attribute instead.
The module defines the following exception:
-
exception
http.cookiejar.
LoadError
¶ Instances of
FileCookieJar
raise this exception on failure to load cookies from a file.LoadError
is a subclass ofOSError
.
The following classes are provided:
-
class
http.cookiejar.
CookieJar
(policy=None)¶ policy is an object implementing the
CookiePolicy
interface.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.
-
class
http.cookiejar.
FileCookieJar
(filename, delayload=None, policy=None)¶ policy is an object implementing the
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 theload()
orrevert()
method is called. Subclasses of this class are documented in section FileCookieJar subclasses and co-operation with web browsers.Змінено в версії 3.8: The filename parameter supports a path-like object.
-
class
http.cookiejar.
CookiePolicy
¶ This class is responsible for deciding whether each cookie should be accepted from / returned to the server.
-
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"))¶ 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 forCookiePolicy
andDefaultCookiePolicy
objects.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 orrfc2109_as_netscape
isTrue
, RFC 2109 cookies are „downgraded“ by theCookieJar
instance to Netscape cookies, by setting theversion
attribute of theCookie
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 ownCookie
instances. Instead, if necessary, callmake_cookies()
on aCookieJar
instance.
Дивись також
- Module
urllib.request
URL opening with automatic cookie handling.
- Module
http.cookies
HTTP cookie classes, principally useful for server-side code. The
http.cookiejar
andhttp.cookies
modules do not depend on each other.- https://curl.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 incookie_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 and FileCookieJar Objects¶
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
andhide_cookie2
attributes of theCookieJar
’sCookiePolicy
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 methodsget_full_url()
,get_host()
,get_type()
,unverifiable()
,has_header()
,get_header()
,header_items()
,add_unredirected_header()
andorigin_req_host
attribute as documented byurllib.request
.Змінено в версії 3.3: request object needs
origin_req_host
attribute. Dependency on a deprecated methodget_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 theCookiePolicy.set_ok()
method’s approval).The response object (usually the result of a call to
urllib.request.urlopen()
, or similar) should support aninfo()
method, which returns anemail.message.Message
instance.The request object (usually a
urllib.request.Request
instance) must support the methodsget_full_url()
,get_host()
,unverifiable()
, andorigin_req_host
attribute, as documented byurllib.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.Змінено в версії 3.3: request object needs
origin_req_host
attribute. Dependency on a deprecated methodget_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
(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 nomax-age
orexpires
cookie-attribute, or an explicitdiscard
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); ifself.filename
isNone
,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()
orrevert()
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.
-
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 asload()
. 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 theFileCookieJar
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 Mozillacookies.txt
file format (which is also used by the Lynx and Netscape browsers).Примітка
This loses information about RFC 2965 cookies, and also about newer or non-standard cookie-attributes such as
port
.Попередження
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’sSet-Cookie3
file format. This is convenient if you want to store cookies in a human-readable file.Змінено в версії 3.8: The filename parameter supports a path-like object.
CookiePolicy Objects¶
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 forCookieJar.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 forCookieJar.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()
andpath_return_ok()
leaves all the work toreturn_ok()
.If
domain_return_ok()
returns true for the cookie domain,path_return_ok()
is called for the cookie path. Otherwise,path_return_ok()
andreturn_ok()
are never called for that cookie domain. Ifpath_return_ok()
returns true,return_ok()
is called with theCookie
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 forpath_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.
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 Objects¶
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 theCookie
instance to 0. The default value isNone
, 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
, becausewww.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 fromexample.com
that had nodomain
cookie-attribute).
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 Objects¶
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 haveversion
0. RFC 2965 and RFC 2109 cookies have aversion
cookie-attribute of 1. However, note thathttp.cookiejar
may „downgrade“ RFC 2109 cookies to Netscape cookies, in which caseversion
is 0.
-
Cookie.
name
¶ Cookie name (a string).
-
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 theis_expired()
method.
-
Cookie.
discard
¶ True
if this is a session cookie.
-
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 becausehttp.cookiejar
may „downgrade“ RFC 2109 cookies to Netscape cookies, in which caseversion
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.
Examples¶
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/")