Issue#1919: Asset root path should be configurable

contributors.md

@@ -276,3 +276,8 @@ Noel Kennedy
 ### Email: ###
 nkennedy at rvc dot ac dot uk
 
+### Name: ###
+Henrik Härkönen
+
+### Email: ###
+heharkon@iki.fi

web/webkit/src/main/scala/net/liftweb/builtin/snippet/LazyLoad.scala

@@ -72,7 +72,7 @@ object LazyLoad extends DispatchSnippet {
               renderedTemplate
             }
           } openOr {
-            <div><img src="/images/ajax-loader.gif" alt="Loading"/></div>
+            <div><img src={s"${LiftRules.assetRootPath}images/ajax-loader.gif"} alt="Loading"/></div>
           }
         )
       }

web/webkit/src/main/scala/net/liftweb/http/LiftRules.scala

@@ -1334,6 +1334,22 @@ class LiftRules() extends Factory with FormVendor with LazyLoggable {
     }
   }
 
+  /**
+    * The root path for the assets folder.
+    *
+    * This applies also to the URL domain, appended after the deployed context path.
+    * In app developer's work area this folder resides under the 'webapp' folder.
+    *
+    * For example to store asset files under 'myassets' folder,
+    * use value '/myassets/'. Assets under this configurable path follow
+    * conventions, for example the default lazy loading spinner ('ajax-loader.gif')
+    * is under 'images' folder.
+    *
+    * Thus the URL to the assets folder would be:
+    * 'http://<domain name>/<context path>/myassets/'
+    */
+  @volatile var assetRootPath: String = "/"
+
   /**
    * Contains the URI path under which all built-in Lift-handled requests are
    * scoped. It does not include the context path and should not begin with a

web/webkit/src/main/scala/net/liftweb/http/package.scala

@@ -55,7 +55,7 @@ package object http {
           // Actually complete the render once the future is fulfilled.
           asyncResolveProvider.resolveAsync(concreteResolvable, resolvedResult => deferredRender(resolvedResult))
 
-          <div id={placeholderId}><img src="/images/ajax-loader.gif" alt="Loading..." /></div>
+          <div id={placeholderId}><img src={s"${LiftRules.assetRootPath}images/ajax-loader.gif"} alt="Loading" /></div>
         } openOr {
           Comment("FIX"+"ME: Asynchronous rendering failed for unknown reason.")
         }