Fix for #380 from Tim Schaub, with test. Don't overwrite already-existing parameters

in the URL. This makes the precedence of parameters: 
 * params in URL
 * params in Layer
 * DEFAULT_PARAMS on the Layer.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@1907 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/HTTPRequest.js

@@ -121,7 +121,15 @@ OpenLayers.Layer.HTTPRequest.prototype =
         // create a new params hashtable with all the layer params and the 
         // new params together. then convert to string
         var allParams = OpenLayers.Util.extend(new Object(), this.params);
-        var allParams = OpenLayers.Util.extend(allParams, newParams);
+        allParams = OpenLayers.Util.extend(allParams, newParams);
+        // ignore parameters that are already in the url search string
+        var urlParams = OpenLayers.Util.upperCaseObject(
+                            OpenLayers.Util.getArgs(url));
+        for(var key in allParams) {
+            if(key.toUpperCase() in urlParams) {
+                delete allParams[key];
+            }
+        }
         var paramsString = OpenLayers.Util.getParameterString(allParams);
         if (paramsString != "") {
             var lastServerChar = url.charAt(url.length - 1);

tests/test_Layer_HTTPRequest.html

@@ -89,7 +89,7 @@
         tParams = { layers: 'basic', 
                    format: 'image/png'};
         
-        t.plan( 8 );
+        t.plan( 9 );
 
   // without ?        
         tUrl = "http://octo.metacarta.com/cgi-bin/mapserv";
@@ -110,6 +110,12 @@
         str = layer.getFullRequestString();
         t.eq(str, "http://octo.metacarta.com/cgi-bin/mapserv?param1=5&layers=basic&format=image/png", "getFullRequestString() works for url with ?param1=5");
   
+  // with ?param1=5&
+        tUrl = "http://octo.metacarta.com/cgi-bin/mapserv?param1=5&format=image/jpeg";
+        layer = new OpenLayers.Layer.HTTPRequest(name, tUrl, tParams, null);
+        str = layer.getFullRequestString();
+        t.eq(str, "http://octo.metacarta.com/cgi-bin/mapserv?param1=5&format=image/jpeg&layers=basic", "getFullRequestString() doesn't override already-existing params in URL");
+
  
   // with ?param1=5&
         tUrl = "http://octo.metacarta.com/cgi-bin/mapserv?param1=5&";
@@ -117,6 +123,8 @@
         str = layer.getFullRequestString();
         t.eq(str, "http://octo.metacarta.com/cgi-bin/mapserv?param1=5&layers=basic&format=image/png", "getFullRequestString() works for url with ?param1=5&");
   
+
+
   // passing in new params
         layer = new OpenLayers.Layer.HTTPRequest(name, tUrl, tParams, null);
         str = layer.getFullRequestString( { chicken: 6,