Add text download service

To add functionality for text download within client-side,
this patch adds text-download.service.
This service realize to download text file from text contents and file name
within  only browser.
This function will be used for download key pair after its creation.

Change-Id: Id079fa38c0ac0e79666fa7c5469afd58bf5228d3

horizon/static/framework/util/file/text-download.service.js

@@ -0,0 +1,66 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+(function() {
+  'use strict';
+
+  angular
+    .module('horizon.framework.util.file')
+    .factory('horizon.framework.util.file.text-download',
+      textDownloadService);
+
+  textDownloadService.$inject = ['$q', '$timeout'];
+
+  /**
+   * @ngdoc service
+   * @name horizon.framework.util.file.textDownloadService
+   * @description
+   * Service for download text contetns as file.  Used for client-side
+   * text file creation and download, such as download a private key
+   * file after key pair creation.
+   */
+  function textDownloadService($q, $timeout) {
+    var service = {
+      downloadTextFile: downloadTextFile
+    };
+
+    return service;
+
+    ////////////////
+
+    function downloadTextFile(text, filename) {
+      // create text file as object url
+      var blob = new Blob([ text ], { "type" : "text/plain" });
+      window.URL = window.URL || window.webkitURL;
+      var fileUrl = window.URL.createObjectURL(blob);
+
+      // provide text as downloaded file
+      var a = angular.element('<a></a>');
+      a.attr("href", fileUrl);
+      a.attr("download", filename);
+      a.attr("target", "_blank");
+      angular.element(document.body).append(a);
+
+      var deferred = $q.defer();
+      // start download after updating view
+      $timeout(startDownload, 0);
+      return deferred.promise;
+
+      function startDownload() {
+        a[0].click();
+        a.remove();
+        deferred.resolve(filename);
+      }
+    }
+  }
+})();

horizon/static/framework/util/file/text-download.service.spec.js

@@ -0,0 +1,34 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+(function() {
+  'use strict';
+
+  describe('textDownloadService', function() {
+    var $scope, textDownload;
+
+    beforeEach(module('horizon.framework.util.file'));
+    beforeEach(inject(function($injector) {
+      textDownload = $injector.get('horizon.framework.util.file.text-download');
+      $scope = $injector.get('$rootScope');
+    }));
+
+    it('should return promise and it resolve filename after starting download file', function() {
+      var promise = textDownload.downloadTextFile('content', 'download_file_name.txt');
+      $scope.$apply();
+      promise.then(function(contents) {
+        expect(contents).toEqual('download_file_name.txt');
+      });
+    });
+  });
+})();