Hide Selected Server in the Search tab when there is only the primary…

… server connected

Closes #437.
select-server.hbs : use this. prefix for component attribute .servers, part of framework upgrade #370.
left-panel.js : alias multipleServers because its basis may change; for hiding Panel::SelectedServer.
api-server.js : featuresCountAllTaskInstance() : call to getBlocksTask / getBlocksLimits : change param blockIds from [] to undefined, i.e. default to all blocks;  passing [] was an error in 126a15a which added this function.
api-servers.js : add multipleServersCP(), which enables panel/left-panel.hbs to update whereas using multipleServers does not.
left-panel.hbs : hide Panel::SelectedServer if not multipleServers.

frontend/app/components/form/select-server.hbs

@@ -1,5 +1,5 @@
   <select onchange={{action (action this.selectedServerChangedName) value="target.value" }}>
-    {{#each-in servers as |apiServerName apiServer| }}
+    {{#each-in this.servers as |apiServerName apiServer| }}
       <option value={{apiServer.tabId}} selected={{eq @selectedValue apiServer}}>{{apiServer.tabId}}</option>
 
     {{/each-in}}

frontend/app/components/panel/left-panel.js

@@ -14,6 +14,12 @@ export default Component.extend({
   attributeBindings: ['style:style'],
   view: 'mapview',
 
+  /** Determine if the 'Selected Server' <Panel::SelectedServer> should be displayed.
+   * There is no need to display it if the number of api servers is 1, i.e. only
+   * connected to the primary pretzel server.
+   */
+  multipleServers : alias('apiServers.multipleServersCP'),
+
   /** Return a list of datasets, with their included blocks, for the currently-selected
    * API server tab
    *

frontend/app/components/service/api-server.js

@@ -285,8 +285,8 @@ const ApiServerAttributes = {
     // (allInitially ? '' : 'Summary')
     let getBlocksTask = blockService.get('getBlocksLimits');
 
-    /** Task Instance.  param blockIds is [] */
-    let getBlocksTI = getBlocksTask.apply(blockService, [[]]);
+    /** Task Instance.  param blockIds is undefined, i.e. default to all blocks */
+    let getBlocksTI = getBlocksTask.apply(blockService, []);
 
     return getBlocksTI;
   }),

frontend/app/services/api-servers.js

@@ -53,6 +53,7 @@ export default Service.extend(Evented, {
 
   /** Map of servers, indexed by server .name */
   servers : EmberObject.create(),
+  // @tracked
   serversLength : 0,
   /** Map from block and dataset ids to their server.
    * Block and dataset ids could be mapped separately, but it is unlikely those
@@ -117,6 +118,18 @@ export default Service.extend(Evented, {
   get multipleServers() {
     return this.serversLength > 1;
   },
+  /** Identical to .multipleServers() which works OK in templates/group{,s}.hbs
+   * (perhaps because that is a route), but it doesn't update in panel/left-panel.hbs;
+   * this updates OK.  Possibly this won't be needed after the service and Component
+   * are converted from classic Ember Components to native classes.
+   *
+   * Copied from components/draw/axis-menu.js, which was based on an extract
+   * from axisTitleBlocksServers_tspan.js
+   */
+  multipleServersCP : computed('serversLength', function () {
+    return this.get('serversLength') > 1;
+  }),
+
 
   /** Add a new ApiServer.
    * Store it in this.servers, indexed by .name = .host_safe()

frontend/app/templates/components/panel/left-panel.hbs

@@ -20,7 +20,11 @@
                 updateFeaturesInBlocks=this.updateFeaturesInBlocks
             }}
 
-            <Panel::SelectedServer/>
+            {{!-- There is no need to display SelectedServer if the number of
+                  api servers is 1, i.e. only connected to the primary pretzel server. --}}
+            {{#if this.multipleServers}}
+              <Panel::SelectedServer/>
+            {{/if}}
 
             {{panel/sequence-search
                 datasets=this.serverSelected_datasetsBlocks