Changeset 2821

Timestamp:

03/19/07 20:00:17 (2 years ago)

Author:

sderle

Message:

Make WMS server selection deterministic, by using a real number hashing algorithm on the parameter string to select the server URL. Also, patch TMS since it doesn't use getFullParameterString(). Passes all tests. Fixes #410.

Files:

• trunk/openlayers/lib/OpenLayers/Layer/HTTPRequest.js (modified) (3 diffs)
• trunk/openlayers/lib/OpenLayers/Layer/TMS.js (modified) (1 diff)
• trunk/openlayers/tests/Layer/test_HTTPRequest.html (modified) (2 diffs)
• trunk/openlayers/tests/Layer/test_TMS.html (modified) (2 diffs)

trunk/openlayers/lib/OpenLayers/Layer/HTTPRequest.js

@@ -91 +91 @@
-    },
-    
+    /**
+     * @param {String} paramString
+     * @param {Array(String)} urls
+     */
+    selectUrl: function(paramString, urls) {
+        var product = 1;
+        for (var i = 0; i < paramString.length; i++) { 
+            product *= paramString.charCodeAt(i) * (Math.sqrt(5) - 1) / Math.sqrt(3);
+            product -= Math.floor(product); 
+        }
+        return urls[Math.floor(product * urls.length)];
+    },
-
-    /** combine url with layer's params and these newParams. 
@@ -110 +122 @@
-        var url = (altUrl == null) ? this.url : altUrl;
-        
-        // if url is not a string, it should be an array of strings, 
-        //  in which case we will randomly select one of them in order
-        //  to evenly distribute requests to different urls.
-        if (typeof url == "object") {
-            url = url[Math.floor(Math.random()*url.length)];
-        }   
-        // requestString always starts with url
-        var requestString = url;        
-
-        // create a new params hashtable with all the layer params and the 
-        // new params together. then convert to string
@@ -132 +135 @@
-        }
-        var paramsString = OpenLayers.Util.getParameterString(allParams);
+        
+        // if url is not a string, it should be an array of strings, 
+        // in which case we will deterministically select one of them in 
+        // order to evenly distribute requests to different urls.
+        if (url instanceof Array) {
+            url = this.selectUrl(paramsString, url);
+        }   
+        
+        // requestString always starts with url
+        var requestString = url;        
+        
-        if (paramsString != "") {
-            var lastServerChar = url.charAt(url.length - 1);

trunk/openlayers/lib/OpenLayers/Layer/TMS.js

@@ -76 +76 @@
-        var y = (bounds.bottom - this.tileOrigin.lat) / (res * this.tileSize.h);
-        var z = this.map.getZoom();
-
+
+
+
+
+
+
-    },
-

trunk/openlayers/tests/Layer/test_HTTPRequest.html

@@ -90 +90 @@
-                   format: 'image/png'};
-        
-9
+12
-
-  // without ?        
@@ -148 +148 @@
-        str = layer.getFullRequestString(null, tUrl);
-        t.eq(str, tUrl + '?' + OpenLayers.Util.getParameterString(tParams), "getFullRequestString() works for url sans ?");
-
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-    }
-

trunk/openlayers/tests/Layer/test_TMS.html

@@ -107 +107 @@
-    function test_10_Layer_TMS_getURL(t) {
-
-1
+2
-        
-        var map = new OpenLayers.Map('map', options);
@@ -116 +116 @@
-        var tileurl = layer.getURL(new OpenLayers.Bounds(3.515625,45,4.21875,45.703125));
-        t.eq(tileurl, "http://labs.metacarta.com/wms-c/Basic.py/1.0.0/basic/9/261/192.png", "Tile URL is correct");
+
+        layer.url = ["http://tilecache1/", "http://tilecache2/", "http://tilecache3/"];
+        tileurl = layer.getURL(new OpenLayers.Bounds(3.515625,45,4.21875,45.703125));
+        t.eq(tileurl, "http://tilecache2/1.0.0/basic/9/261/192.png", "Tile URL is deterministic");
-    }
-