Initial import of Session Tool (portal_sessions).

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@12631 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/Tool/SessionTool.py

+##############################################################################
+#
+# Copyright (c) 2002, 2005 Nexedi SARL and Contributors. All Rights Reserved.
+#                    Ivan Tyagov <ivan@nexedi.com>
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsability of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# garantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# This program is Free Software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+##############################################################################
+
+from AccessControl import ClassSecurityInfo
+from Products.ERP5Type.Tool.BaseTool import BaseTool
+from Products.ERP5Type.Cache import CachingMethod
+from Products.ERP5Type import Permissions
+from Acquisition import aq_base
+from time import time
+from UserDict import UserDict
+
+_marker=[]
+
+def wrapper():
+  """ Simple cache call wrapper."""
+  s = Session()
+  return s
+
+class Session(UserDict):
+  """ Session object acts as a plain python dictionary but can wrap/unwarp ZODB
+      RAM object (newTempOrder, newTempDocument..) in order to safely store it inside. 
+      Please be AWARE that there's no security checks applied! """
+   
+  ## we have our own security policy and do not want Zope's
+  _guarded_writes = 1 
+  __allow_access_to_unprotected_subobjects__ = 1
+  
+  ## a handle to current aquisition context
+  _aq_context = None
+  
+  def _updatecontext(self, aq_context):
+    """ Update current aquisition context. """
+    self._aq_context = aq_context
+  
+  def __getattr__(self, key):
+    return self.__getitem__(key)
+  
+  def __getitem__(self, key):
+    value = self.data.get(key, None)
+    if key is not None and hasattr(value, '__of__'):
+      value = value.__of__(self._aq_context)
+    return value
+    
+  def __setitem__(self, key, item):
+    self.data[key] = aq_base(item)
+    
+  def __str__(self):
+    return self.__repr__()
+    
+  def edit(self, **kw):
+    """ Edit session object. """
+    for key, item in kw.items():
+      self.__setitem__(key, item)
+ 
+class SessionTool(BaseTool):
+  """ Using this tool you can get a RAM based session object by providing 
+      your own generated session_id. 
+            
+      This session object can be used anywhere in Zope/ERP5 environment. 
+      Because it uses lazy Cache as a storage backend you do not need to initialize it
+      (Cache will take care for that first time it's called).
+      
+      Example:
+      
+      session_id = '1234567'
+      session = context.portal_sessions[session_id]
+      session['shopping_cart'] = newTempOrder(context, '987654321')
+      (you can also use 'session.edit(shopping_cart= newTempOrder(context, '987654321'))' )
+      
+      (later in another script you can acquire shopping_cart):
+      
+      session_id = '1234567'
+      session = context.portal_sessions[session_id]
+      shopping_cart = session['shopping_cart']
+      
+      Please note that:
+       - developer is responsible for handling an uniform sessiond_id (using cookies for example). 
+       - it's not recommended to store in portal_sessions ZODB persistent objects because in order 
+       to store them in Cache(RAM) portal_sessions tool will remove aquisition wrapper. At "get" 
+       request they'll be returend wrapped. 
+       - it's recommended that developer store temporary RAM based objects like 'TempOrder'
+      """
+    
+  id = 'portal_sessions'
+  meta_type = 'ERP5 Session Tool'    
+  portal_type = 'Session Tool'
+  allowed_types = ()
+  security = ClassSecurityInfo()
+  
+  ## the ERP5 cache factory used as a storage
+  _cache_factory = 'erp5_session_cache'
+     
+  def __getitem__(self, key):
+    session = self._getSessionObject(key)
+    session._updatecontext(self)
+    return session
+    
+  def __setitem__(self, key, item):
+    session = self._getSessionObject(session_id)
+    session._updatecontext(self)
+
+  def newContent(self, id, **kw):
+    """ Create new session object. """
+    session =  self._getSessionObject(id)
+    session._updatecontext(self)
+    session.edit(**kw)
+    return session
+         
+  security.declareProtected(Permissions.ModifyPortalContent, 'manage_delObjects')
+  def manage_delObjects(self, ids=[], REQUEST=None):
+    """ Delete session object. """
+    if not isinstance(ids, list) or isinstance(ids, list):
+      ids = [ids]
+    for session_id in ids:
+      cache_method = self._getCacheMethod(session_id)
+      cache_method.delete(session_id)
+ 
+  def _getCacheMethod(self, session_id):
+    """ Get caching method used to interact with Cache system. """
+    cache_method = CachingMethod(callable_object = wrapper, \
+                                 id = session_id, \
+                                 cache_factory = self._cache_factory)
+    return cache_method
+    
+  def _getSessionObject(self, session_id):
+    """ Return session object. """
+    return self._getCacheMethod(session_id)()