The Cookie.Cookie class does not allow the new "httponly" cookie property to be set. It needs to be added to the valid slots on the cookie metaclass. Also note that like the "secure" cookie attribute, it is simple a boolean flag without any value.
The HttpOnly flag was invented by Microsoft but seeing widespread support as a way to prevent cross-site scripting from stealing cookies using client-side Javascript. This is especially important for security-sensitive cookies, such as session keys.
The mod_python session object should also explicitly set the HttpOnly property on the cookies it creates.
Added support to cookies for "httponly" attribute, an extension originally
created by Microsoft, but now getting more widespread use in the battle
against cross site-scripting attacks. (MODPYTHON-108)