Redo branch & pr for registry (#36)

* Redo branch & pr for registry

* fix lint ignore file

js/utils/getRegistry.js

@@ -0,0 +1,58 @@
+'use strict';
+
+const symphonyRegistry = '\\Software\\Symphony\\Symphony\\';
+const { isMac } = require('./misc.js');
+
+var Registry = require('winreg');
+var symphonyRegistryHKCU = new Registry({
+    hive: Registry.HKCU,
+    key:  symphonyRegistry
+});
+
+var symphonyRegistryHKLM = new Registry({
+    key:  symphonyRegistry
+});
+
+var symphonyRegistryHKLM6432 = new Registry({
+    key:  symphonyRegistry.replace('\\Software','\\Software\\WOW6432Node')
+});
+    
+/**
+ * Reads Windows Registry key. This Registry holds the Symphony registry keys 
+ * that are intended to be used as global (or default) value for all users 
+ * running this app.
+ */
+var getRegistry = function (name) {
+    var promise = new Promise(function(resolve, reject) {
+        if (isMac){
+            reject('Mac OS. Using default url from config.json.');
+        } else{
+            //Try to get registry on HKEY_CURRENT_USER    
+            symphonyRegistryHKCU.get( name, function( err1, reg1 ) {
+                if ( !err1 && reg1!==null && reg1.value) {
+                    resolve(reg1.value);
+                } else{
+                    //Try to get registry on HKEY_LOCAL_MACHINE                    
+                    symphonyRegistryHKLM.get( name, function( err2, reg2 ) {
+                        if ( !err2 && reg2!==null && reg2.value) {
+                            resolve(reg2.value);
+                        } else{
+                            //Try to get registry on HKEY_LOCAL_MACHINE in case 32bit app installed on 64bit system.
+                            //winreg does not merge keys as normally windows does.
+                            symphonyRegistryHKLM6432.get( name, function( err3, reg3 ) {
+                                if ( !err3 && reg3!==null && reg3.value) {
+                                    resolve(reg3.value);
+                                } else{
+                                    reject('Cannot find PodUrl Registry. Using default url.');
+                                }
+                            });
+                        }
+                    });
+                }
+            });
+        }
+    });
+    return promise;
+}
+
+module.exports = getRegistry