diff -r 3edd2f19bce2 -r e0424e96e3fd svgui/svgui_server.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/svgui/svgui_server.py	Sat May 12 11:21:10 2012 +0200
@@ -0,0 +1,130 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+import os
+
+from nevow import rend, appserver, inevow, tags, loaders, athena
+import simplejson as json
+
+svgfile = '%(svgfile)s'
+
+svguiWidgets = {}
+
+currentId = 0
+def getNewId():
+    global currentId
+    currentId += 1
+    return currentId
+
+class SvguiWidget:
+    
+    def __init__(self, classname, id, **kwargs):
+        self.classname = classname
+        self.id = id
+        self.attrs = kwargs.copy()
+        self.inputs = {}
+        self.outputs = {}
+        self.inhibit = False
+        self.changed = False
+
+    def setinput(self, attrname, value):
+        self.inputs[attrname] = value
+        
+    def getinput(self, attrname, default=None):
+        if not self.inputs.has_key(attrname):
+            self.inputs[attrname] = default
+        return self.inputs[attrname]
+
+    def setoutput(self, attrname, value):
+        if self.outputs.get(attrname) != value:
+            self.outputs[attrname] = value
+            self.changed = True
+            self.RefreshInterface()
+        
+    def updateoutputs(self, **kwargs):
+        for attrname, value in kwargs.iteritems():
+            if self.outputs.get(attrname) != value:
+                self.outputs[attrname] = value
+                self.changed = True
+        self.RefreshInterface()
+        
+    def RefreshInterface(self):
+        interface = website.getHMI()
+        if isinstance(interface, SVGUI_HMI) and self.changed and not self.inhibit:
+            self.changed = False
+            d = interface.sendData(self)
+            if d is not None:
+                self.inhibit = True
+                d.addCallback(self.InterfaceRefreshed)
+    
+    def InterfaceRefreshed(self, result):
+        self.inhibit = False
+        if self.changed:
+            self.RefreshInterface()
+
+def get_object_init_state(obj):
+    # Convert objects to a dictionary of their representation
+    attrs = obj.attrs.copy()
+    attrs.update(obj.inputs)
+    d = { '__class__': obj.classname,
+          'id': obj.id,
+          'kwargs': json.dumps(attrs),
+          }
+    return d
+
+def get_object_current_state(obj):
+    # Convert objects to a dictionary of their representation
+    d = { '__class__': obj.classname,
+          'id': obj.id,
+          'kwargs': json.dumps(obj.outputs),
+          }
+    return d
+
+class SVGUI_HMI(website.PLCHMI):
+    jsClass = u"LiveSVGPage.LiveSVGWidget"
+    
+    docFactory = loaders.stan(tags.div(render=tags.directive('liveElement'))[                                    
+                                         tags.xml(loaders.xmlfile(os.path.join(WorkingDir, svgfile))),
+                                         ])
+    
+    def HMIinitialisation(self):
+        gadgets = []
+        for gadget in svguiWidgets.values():
+            gadgets.append(unicode(json.dumps(gadget, default=get_object_init_state, indent=2), 'ascii'))
+        d = self.callRemote('init', gadgets)
+        d.addCallback(self.HMIinitialised)
+    
+    def sendData(self,data):
+        if self.initialised:
+            return self.callRemote('receiveData',unicode(json.dumps(data, default=get_object_current_state, indent=2), 'ascii'))
+        return None
+        
+    def setattr(self, id, attrname, value):
+        svguiWidgets[id].setinput(attrname, value)
+
+def createSVGUIControl(*args, **kwargs):
+    id = getNewId()
+    gad = SvguiWidget(args[0], id, **kwargs)
+    svguiWidgets[id] = gad
+    gadget = [unicode(json.dumps(gad, default=get_object_init_state, indent=2), 'ascii')]
+    interface = website.getHMI()
+    if isinstance(interface, SVGUI_HMI) and interface.initialised:
+        interface.callRemote('init', gadget)
+    return id
+
+def setAttr(id, attrname, value):
+    gad = svguiWidgets.get(id, None)
+    if gad is not None:
+        gad.setoutput(attrname, value)
+
+def updateAttr(id, **kwargs):
+    gad = svguiWidgets.get(id, None)
+    if gad is not None:
+        gad.updateoutput(**kwargs)
+
+def getAttr(id, attrname, default=None):
+    gad = svguiWidgets.get(id, None)
+    if gad is not None:
+        return gad.getinput(attrname, default)
+    return default
+