MXS-1782: Separate resource fetching and processing

The requesting of a resource and the processing was integrated into one
function. Moving the processing part into a separate function allows easy
processing of resource collections.

This refactoring made the creation of the getCollectionAsResource function
possible. It enables `show` type commands for resouce collections
(servers, services etc.).

maxctrl/lib/common.js

@@ -169,16 +169,13 @@ module.exports = function() {
         })
     }
 
-    // Request a single resource and format it as a key-value list
-    this.getResource = function (host, resource, fields) {
-
-        return doRequest(host, resource, function(res) {
+    this.formatResource = function (fields, data) {
         var table = getList()
 
         fields.forEach(function(i) {
             var k = Object.keys(i)[0]
             var path = i[k]
-                var v = _.getPath(res.data, path, '')
+            var v = _.getPath(data, path, '')
 
             if (Array.isArray(v) && typeof(v[0]) != 'object') {
                 v = v.join(', ')
@@ -192,6 +189,19 @@ module.exports = function() {
         })
 
         return tableToString(table)
+    }
+
+    // Request a single resource and format it as a key-value list
+    this.getResource = function (host, resource, fields) {
+        return doRequest(host, resource, (res) => {
+            return formatResource(fields, res.data)
+        })
+    }
+
+    this.getCollectionAsResource = function(host, resource, fields) {
+        return doRequest(host, resource, (res) => {
+            //return formatResource(fields, res.data[0])
+            return res.data.map((i) => formatResource(fields, i)).join('\n')
         })
     }