SOLR-4456: Admin UI: Displays dashboard even if Solr is down

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1494765 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -177,6 +177,7 @@ Bug Fixes
 * SOLR-4934: Fix handling of <mergePolicy> init arg "useCompoundFile" needed 
   after changes in LUCENE-5038 (hossman)
 
+* SOLR-4456: Admin UI: Displays dashboard even if Solr is down (steffkes)
 
 Optimizations
 ----------------------

solr/webapp/web/admin.html

@@ -138,6 +138,12 @@ limitations under the License.
     </div>
     
   </div>
+
+  <div id="connection_status">
+
+    <span>Connection lost …</span>
+
+  </div>
   
   <script type="text/javascript"> var require = { urlArgs: '_=${version}' }; </script>
   <script src="js/require.js?_=${version}" data-main="js/main"></script>

solr/webapp/web/css/styles/common.css

@@ -605,4 +605,39 @@ pre.syntax .tex .formula
 #content .tree a.jstree-search
 {
   color:aqua;
+}
+
+#connection_status
+{
+  display: none;
+  padding: 30px;
+}
+
+#connection_status span
+{
+  background-image: url( ../../img/ico/network-status-busy.png );
+  background-position: 0 50%;
+  color: #800;
+  padding-left: 26px;
+}
+
+#connection_status.online span,
+#connection_status.online span a
+{
+  color: #080;
+}
+
+#connection_status.online span
+{
+  background-image: url( ../../img/ico/network-status.png );
+}
+
+#connection_status.online span a
+{
+  text-decoration: underline;
+}
+
+#connection_status.online span a:hover
+{
+  text-decoration: none;
 }

solr/webapp/web/js/scripts/app.js

@@ -585,5 +585,74 @@ var solr_admin = function( app_config )
 
 };
 
+var connection_check_delay = 1000;
+var connection_working = true;
+
+var connection_check = function connection_check()
+{
+  $.ajax
+  (
+    {
+      url : config.solr_path + config.core_admin_path + '?wt=json&indexInfo=false',
+      dataType : 'json',
+      context : $( '.blockUI #connection_status span' ),
+      beforeSend : function( arr, form, options )
+      {               
+        this
+          .addClass( 'loader' );
+      },
+      success : function( response )
+      {
+        connection_working = true;
+
+        this
+          .html( 'Instance is available - <a href="javascript:location.reload();">Reload the page</a>' );
+
+        this.parents( '#connection_status' )
+          .addClass( 'online' );
+
+        this.parents( '.blockUI' )
+          .css( 'borderColor', '#080' );
+      },
+      error : function()
+      {
+        connection_check_delay += connection_check_delay;
+        window.setTimeout( connection_check, connection_check_delay );
+      },
+      complete : function()
+      {
+        this
+          .removeClass( 'loader' );
+      }
+    }
+  );
+};
+
+var connection_error = function connection_error()
+{
+  connection_working = false;
+
+  $.blockUI
+  (
+    {
+      message: $( '#connection_status' ),
+      css: { width: '450px', borderColor: '#f00' }
+    }
+  );
+
+  window.setTimeout( connection_check, connection_check_delay );
+}
+
+$( document ).ajaxError
+(
+  function( event, xhr, settings, thrownError )
+  {
+    if( connection_working && 0 === xhr.status )
+    {
+      connection_error();
+    }
+  }
+);
+
 $.ajaxSetup( { cache: false } );
 var app = new solr_admin( app_config );