add state-dependent control of actions and a doBefore handler for transitions

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@3240 fd906abe-77d9-0310-91a1-e0d9ade77398

stateful/base.py

@@ -142,5 +142,3 @@ class TransitionEvent(ObjectEvent):
         self.transition = transition
         self.previousState = previousState
         self.request = request
-
-

stateful/definition.py

@@ -25,7 +25,7 @@ $Id$
 from zope.interface import implements
 from cybertools.util.jeep import Jeep
 
-from cybertools.stateful.interfaces import IState, ITransition
+from cybertools.stateful.interfaces import IState, IAction, ITransition
 from cybertools.stateful.interfaces import IStatesDefinition
 
 
@@ -33,7 +33,7 @@ class State(object):
 
     implements(IState)
 
-    security = lambda context: None
+    setSecurity = lambda self, context: None
     icon = None
     color = 'blue'
 
@@ -41,20 +41,37 @@ class State(object):
         self.name = self.__name__ = name
         self.title = title
         self.transitions = transitions
+        self.actions = Jeep(kw.pop('actions', []))
         for k, v in kw.items():
             setattr(self, k, v)
 
 
-class Transition(object):
+class Action(object):
+
+    implements(IAction)
+
+    allowed = True
+    permission = None
+    roles = []
+
+    def __init__(self, name, title=None, **kw):
+        self.name = self.__name__ = name
+        self.title = title
+        for k, v in kw.items():
+            setattr(self, k, v)
+
+    @staticmethod
+    def doBefore(context):
+        return None
+
+
+class Transition(Action):
 
     implements(ITransition)
 
     def __init__(self, name, title, targetState, **kw):
-        self.name = self.__name__ = name
-        self.title = title
+        super(Transition, self).__init__(name, title, **kw)
         self.targetState = targetState
-        for k, v in kw.items():
-            setattr(self, k, v)
 
 
 class StatesDefinition(object):
@@ -81,14 +98,36 @@ class StatesDefinition(object):
     def doTransitionFor(self, obj, transition):
         if transition not in self.transitions:
             raise ValueError('Transition %s is not available.' % transition)
-        if transition not in [t.name for t in self.getAvailableTransitionsFor(obj)]:
+        trans = self.transitions[transition]
+        if not self.isAllowed(trans, obj):
+            raise ValueError('Transition %s is not allowed.' % transition)
+        if trans not in self.getAvailableTransitionsFor(obj):
             raise ValueError("Transition '%s' is not reachable from state '%s'."
                                     % (transition, obj.getState()))
-        obj.state = self.transitions[transition].targetState
+        trans.doBefore(obj)
+        obj.state = trans.targetState
+        obj.getStateObject().setSecurity(obj)
 
     def getAvailableTransitionsFor(self, obj):
         state = obj.getState()
-        return [self.transitions[t] for t in self.states[state].transitions]
+        return [self.transitions[t]
+                    for t in self.states[state].transitions
+                    if self.isAllowed(self.transitions[t], obj)]
+
+    def isAllowed(self, action, obj):
+        if not action.allowed:
+            return False
+        if not self.checkRoles(action.roles, obj):
+            return False
+        if not self.checkPermission(action.permission, obj):
+            return False
+        return True
+
+    def checkRoles(self, roles, obj):
+        return True
+
+    def checkPermission(self, permission, obj):
+        return True
 
 
 # dummy default states definition
@@ -101,6 +140,7 @@ defaultSD = StatesDefinition('default',
 
 
 # states definitions registry
+# TODO: use a utility!!!
 
 statesDefinitions = dict()
 

stateful/interfaces.py

@@ -1,5 +1,5 @@
 #
-#  Copyright (c) 2008 Helmut Merz helmutm@cy55.de
+#  Copyright (c) 2009 Helmut Merz helmutm@cy55.de
 #
 #  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
@@ -33,18 +33,31 @@ class IState(Interface):
 
     name = Attribute('The name or identifier of the state')
     title = Attribute('A user-readable name or title of the state')
-    transitions = Attribute('A sequence of strings naming the transitions '
-                    'that can be executed from this state')
-    security = Attribute('A callable setting the security settings for '
-                    'an object in this state when executed.')
+    transitions = Attribute('A collection of strings naming the transitions '
+                    'that can be executed from this state.')
+    actions = Attribute('A mapping with actions that may be executed in '
+                    'this state.')
+    setSecurity = Attribute('A callable (argument: stateful object) '
+                    'for setting the security settings on the object.')
 
 
-class ITransition(Interface):
+class IAction(Interface):
+
+    name = Attribute('The name or identifier of the action.')
+    title = Attribute('A user-readable name or title of the action.')
+    allowed = Attribute('A boolean; if False the action may not be executed.')
+    doBefore = Attribute('A callable (argument: stateful object) to be executed '
+                    'before this action.')
+    roles = Attribute('A collection of names of the roles that are allowed '
+                    'to execute this action; no check when empty.')
+    permission = Attribute('The name of a permission that is needed for '
+                    'executing this action; no check when empty.')
+
+
+class ITransition(IAction):
 
-    name = Attribute('The name or identifier of the transition')
-    title = Attribute('A user-readable name or title of the transition')
     targetState = Attribute('A string naming the state that will be the '
-                    'result of executing this transition')
+                    'result of executing this transition.')
 
 
 class IStateful(Interface):
@@ -119,9 +132,24 @@ class IStatesDefinition(Interface):
         """ Return the transitions available for this object in its current state.
         """
 
+    def isAllowed(action, object):
+        """ Return True if the action (an IAction provider) is allowed on
+            the object given for the current user.
+        """
+
+    def checkRoles(roles, object):
+        """ Return True if the current user provides one of the roles given
+            on the object given.
+        """
+
+    def checkRoles(permission, object):
+        """ Return True if the current user has the permission given
+            on the object given.
+        """
+
 
 class IStatefulIndexInfo(Interface):
-    """ Provide a list of tokens to be used for index the states
+    """ Provide a list of tokens to be used for indexing the states
         of an object in the catalog.
     """
 
@@ -133,7 +161,7 @@ class IStatefulIndexInfo(Interface):
 
 
 class ITransitionEvent(IObjectEvent):
-    """ Fires when the state of an object is changed.
+    """ Fires when the state of an object has been changed.
     """
 
     transition = Attribute('The transition.')