18.22.3 CookiePolicy Objects

Objects implementing the CookiePolicy interface have the following methods:

set_ok( cookie, request): Return boolean value indicating whether cookie should be accepted from server.
cookie is a cookielib.Cookie instance. request is an object implementing the interface defined by the documentation for CookieJar.extract_cookies().

return_ok( cookie, request): Return boolean value indicating whether cookie should be returned to server.
cookie is a cookielib.Cookie instance. request is an object implementing the interface defined by the documentation for CookieJar.add_cookie_header().

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().

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.

netscape: Implement Netscape protocol.

rfc2965: Implement RFC 2965 protocol.

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).

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