Adding refresh event and making TileManager listen for it

ahocevar · ahocevar · commit 26111d00b0e4 · 2013-07-11T13:37:55.000+02:00
When calling redraw(true) on a HTTPRequest layer, mergeNewParams is used to
add a url parameter with a random value. For layer types that do not use
params in the getURL function, the url does not change and the TileManager
will provide tiles from the cache. To make sure that tiles are fetched from
the server, they need to be removed from the cache first.
diff --git a/lib/OpenLayers/Layer/HTTPRequest.js b/lib/OpenLayers/Layer/HTTPRequest.js
@@ -16,6 +16,15 @@
  */
 OpenLayers.Layer.HTTPRequest = OpenLayers.Class(OpenLayers.Layer, {
 
+    /**
+     * APIProperty: events
+     * {<OpenLayers.Events>}
+     *
+     * Supported event types (in addition to those from <OpenLayers.Layer.events>):
+     * refresh - Triggered when a redraw is forced, to re-fetch data from the
+     *     server.
+     */
+
     /** 
      * Constant: URL_HASH_FACTOR
      * {Float} Used to hash URL param strings for multi-WMS server selection.
@@ -144,6 +153,7 @@ OpenLayers.Layer.HTTPRequest = OpenLayers.Class(OpenLayers.Layer, {
      */
     redraw: function(force) { 
         if (force) {
+            this.events.triggerEvent('refresh');
             return this.mergeNewParams({"_olSalt": Math.random()});
         } else {
             return OpenLayers.Layer.prototype.redraw.apply(this, []);
diff --git a/lib/OpenLayers/TileManager.js b/lib/OpenLayers/TileManager.js
@@ -215,6 +215,7 @@ OpenLayers.TileManager = OpenLayers.Class({
         if (layer instanceof OpenLayers.Layer.Grid) {
             layer.events.on({
                 addtile: this.addTile,
+                refresh: this.refresh,
                 retile: this.clearTileQueue,
                 scope: this
             });
@@ -245,6 +246,7 @@ OpenLayers.TileManager = OpenLayers.Class({
             if (layer.events) {
                 layer.events.un({
                     addtile: this.addTile,
+                    refresh: this.refresh,
                     retile: this.clearTileQueue,
                     scope: this
                 });
@@ -260,6 +262,27 @@ OpenLayers.TileManager = OpenLayers.Class({
             }
         }
     },
+
+    /**
+     * Method: refresh
+     * Clears the cache when a redraw is forced on a layer
+     *
+     * Parameters:
+     * evt - {Object} The listener argument
+     */
+    refresh: function(evt) {
+        var layer = evt.object;
+        if (layer.grid) {
+            var i, j, tile;
+            for (i=layer.grid.length-1; i>=0; --i) {
+                for (j=layer.grid[i].length-1; j>=0; --j) {
+                    tile = layer.grid[i][j];
+                    OpenLayers.Util.removeItem(this.tileCacheIndex, tile.url);
+                    delete this.tileCache[tile.url];
+                }
+            }
+        }
+    },
     
     /**
      * Method: updateTimeout
diff --git a/tests/TileManager.html b/tests/TileManager.html
@@ -129,6 +129,27 @@
             t.eq(tileManager.tileQueue[map.id].length, 0, "tiles loaded after moveDelay");
         });
     }
+
+    function test_refresh(t) {
+        t.plan(1);
+        var map = new OpenLayers.Map( 'map', {maxResolution: 1.40625/2} );
+        var layer = new OpenLayers.Layer.TMS( "TMS",
+                "../img/blank.gif/", {layername: 'basic', type:'png'} );
+        map.addLayer(layer);
+        map.setCenter(new OpenLayers.LonLat(5, 40), 5);
+        var log = 0;
+        t.delay_call(1, function() {
+            var origSetImgSrc = OpenLayers.Tile.Image.prototype.setImgSrc;
+            OpenLayers.Tile.Image.prototype.setImgSrc = function() {
+                ++log;
+                OpenLayers.Tile.Image.prototype.setImgSrc = origSetImgSrc;
+            };
+            layer.redraw(true);
+        });
+        t.delay_call(1.5, function() {
+            t.ok(log > 0, 'setImgSrc called to refresh tile.');
+        });
+    }
   </script>
 </head>
 <body>
