From 36ae91856c01f65ce3e178d2c16d66460de73a9e Mon Sep 17 00:00:00 2001
From: maniac103 <dannybaumann@web.de>
Date: Sat, 25 May 2019 10:12:11 +0200
Subject: [PATCH] Always send correct 'item' member in SSE events (#691)

* Make sure to always send the correct 'item' member in SSE events.

If a change to item A causes visibility changes to item B, we previously
sent an SSE event for B including the new visibility for B, but included
item and state of A. This leads to client confusion, as it'll update its
internal state for the widget belonging to B with the item state of A.
Make sure to always send the item for B and to omit state in that case.

Closes #690

Signed-off-by: Danny Baumann <dannybaumann@web.de>
---
 .../sitemap/internal/PageChangeListener.java  | 24 +++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/eclipse/smarthome/io/rest/sitemap/internal/PageChangeListener.java b/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/eclipse/smarthome/io/rest/sitemap/internal/PageChangeListener.java
index fbe225a3b6e..d4f235f0541 100644
--- a/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/eclipse/smarthome/io/rest/sitemap/internal/PageChangeListener.java
+++ b/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/eclipse/smarthome/io/rest/sitemap/internal/PageChangeListener.java
@@ -216,7 +216,8 @@ private Set<SitemapEvent> constructSitemapEvents(Item item, State state, List<Wi
                 events.addAll(constructSitemapEvents(item, state, itemUIRegistry.getChildren((Frame) w)));
             }
 
-            boolean skipWidget = (w.getItem() == null) || !w.getItem().equals(item.getName());
+            boolean itemBelongsToWidget = w.getItem() != null && w.getItem().equals(item.getName());
+            boolean skipWidget = !itemBelongsToWidget;
             // We skip the chart widgets having a refresh argument
             if (!skipWidget && w instanceof Chart) {
                 Chart chartWidget = (Chart) w;
@@ -231,15 +232,18 @@ private Set<SitemapEvent> constructSitemapEvents(Item item, State state, List<Wi
                 event.valuecolor = itemUIRegistry.getValueColor(w);
                 event.widgetId = itemUIRegistry.getWidgetId(w);
                 event.visibility = itemUIRegistry.getVisiblity(w);
-                // event.item contains data from the item including its state (in event.item.state)
+                // event.item contains the (potentially changed) data of the item belonging to
+                // the widget including its state (in event.item.state)
+                final Item itemToBeSent = itemBelongsToWidget ? item : getItemForWidget(w);
                 String widgetTypeName = w.eClass().getInstanceTypeName()
                         .substring(w.eClass().getInstanceTypeName().lastIndexOf(".") + 1);
                 boolean drillDown = "mapview".equalsIgnoreCase(widgetTypeName);
                 Predicate<Item> itemFilter = (i -> i.getType().equals(CoreItemFactory.LOCATION));
-                event.item = EnrichedItemDTOMapper.map(item, drillDown, itemFilter, null, null);
+                event.item = EnrichedItemDTOMapper.map(itemToBeSent, drillDown, itemFilter, null, null);
 
                 // event.state is an adjustment of the item state to the widget type.
-                event.state = itemUIRegistry.convertState(w, item, state).toFullString();
+                final State stateToBeSent = itemBelongsToWidget ? state : itemToBeSent.getState();
+                event.state = itemUIRegistry.convertState(w, itemToBeSent, stateToBeSent).toFullString();
                 // In case this state is identical to the item state, its value is set to null.
                 if (event.state != null && event.state.equals(event.item.state)) {
                     event.state = null;
@@ -251,6 +255,18 @@ private Set<SitemapEvent> constructSitemapEvents(Item item, State state, List<Wi
         return events;
     }
 
+    private Item getItemForWidget(Widget w) {
+        final String itemName = w.getItem();
+        if (itemName != null) {
+            try {
+                return itemUIRegistry.getItem(itemName);
+            } catch (ItemNotFoundException e) {
+                // fall through to returning null
+            }
+        }
+        return null;
+    }
+
     private boolean definesVisibilityOrColor(Widget w, String name) {
         for (VisibilityRule rule : w.getVisibility()) {
             if (name.equals(rule.getItem())) {