##############################################################################
#
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
# This code is a modified version of CMFCore's CachingPolicyManager.py
"""Caching tool implementation.

$Id: CachingPolicyManager.py 40138 2005-11-15 17:47:37Z jens $
"""

import os

from Globals import package_home
from AccessControl import ClassSecurityInfo
from Globals import InitializeClass
from Globals import DTMLFile

from Products.CMFCore import permissions
from Products.CMFCore.utils import getToolByName
from Products.CMFCore.CachingPolicyManager import CachingPolicyManager as CMFCachingPolicyManager

from Products.CacheSetup.config import CACHE_TOOL_ID

class CSCachingPolicyManager( CMFCachingPolicyManager ):
    """
        Manage the set of CachingPolicy objects for the site;  dispatch
        to them from skin methods.
    """

    id = 'caching_policy_manager'
    meta_type = 'CacheFu Caching Policy Manager'

    security = ClassSecurityInfo()

    security.declareProtected(permissions.ManagePortal, 'manage_cachingPolicies')
    manage_cachingPolicies = DTMLFile('cachingPoliciesDummy', os.path.dirname(package_home(globals())))

    # A new method that replaces getHTTPCachingHeaders
    security.declareProtected( permissions.View, 'getHeadersToAddAndRemove' )
    def getHeadersToAddAndRemove( self, content, view_method, keywords, time=None):
        """Return a tuple of HTTP caching headers, (headers_to_add, headers_to_remove).
           The first item is a list of headers to add to the response in the form
           (header name, header value).  The second item is a list of headers that
           should be removed (before adding)."""
        pcs = getToolByName(self, CACHE_TOOL_ID, None)
        if pcs is None or not pcs.getEnabled():
            return ()
        member = pcs.getMember()
        request = content.REQUEST
        (rule, header_set) = pcs.getRuleAndHeaderSet(request, content, view_method, member)
        if header_set:
            expr_context = rule._getExpressionContext(request, content, view_method, member)
            return header_set.getHeaders(expr_context)
        return ()

    #
    #   'portal_caching' interface methods
    #
    security.declareProtected( permissions.View, 'getHTTPCachingHeaders' )
    def getHTTPCachingHeaders( self, content, view_method, keywords, time=None):
        """Return a list of HTTP caching headers based on 'content', 'view_method', and 'keywords'."""
        hdrs = self.getHeadersToAddAndRemove(content, view_method, keywords, time)
        if hdrs:
            return hdrs[0]
        return ()

    security.declareProtected( permissions.View, 'getModTimeAndETag' )
    def getModTimeAndETag( self, content, view_method, keywords, time=None):
        """ Return the modification time and ETag for the content object,
            view method, and keywords as the tuple (modification_time, etag,
            set_last_modified_header), where modification_time is a DateTime,
            or None.
        """
        pcs = getToolByName(self, CACHE_TOOL_ID, None)
        if pcs is None or not pcs.getEnabled():
            return None
        member = pcs.getMember()
        request = content.REQUEST
        (rule, header_set) = pcs.getRuleAndHeaderSet(request, content, view_method, member)
        if header_set:
            expr_context = rule._getExpressionContext(request, content, view_method, member)
            etag = header_set.getEtagValue(expr_context)
            mod_time = header_set.getLastModifiedValue(expr_context)
            use_mod_time = header_set.getLastModified()
            return (mod_time, etag, use_mod_time)

    security.declareProtected( permissions.View, 'getETag' )
    def getETag( self, content, view_method, keywords, time=None):
        """ Return the ETag for the content object; ignores getEnable304s setting"""
        pcs = getToolByName(self, CACHE_TOOL_ID, None)
        if pcs is None or not pcs.getEnabled():
            return None
        member = pcs.getMember()
        request = content.REQUEST
        (rule, header_set) = pcs.getRuleAndHeaderSet(request, content, view_method, member)
        if header_set:
            expr_context = rule._getExpressionContext(request, content, view_method, member)
            etag = header_set.getEtagValue(expr_context)
            return etag

InitializeClass( CSCachingPolicyManager )