[ADF-1443] Refactor Download directive (#4028)

* [ADF-1443] Refactor Download directive

* [ADF-1443] Node Download Directive now accepts single node and an array as input

* [ADF-1443] Fix Unit tests

* [ADF-1443] Fix unit test related to viewer component

lib/core/services/download-zip.service.ts

@@ -0,0 +1,60 @@
+/*!
+ * @license
+ * Copyright 2016 Alfresco Software, Ltd.
+ *
+ * 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.
+ */
+
+import { NodeEntry, DownloadEntry, DownloadBodyCreate } from 'alfresco-js-api';
+import { Injectable } from '@angular/core';
+import { Observable, from, throwError } from 'rxjs';
+import { LogService } from './log.service';
+import { AlfrescoApiService } from './alfresco-api.service';
+import { catchError } from 'rxjs/operators';
+
+@Injectable({
+    providedIn: 'root'
+})
+export class DownloadZipService {
+
+    constructor(private apiService: AlfrescoApiService,
+                private logService: LogService) {
+    }
+
+    createDownload(payload: DownloadBodyCreate): Observable<DownloadEntry> {
+        return from(this.apiService.getInstance().core.downloadsApi.createDownload(payload)).pipe(
+            catchError((err) => this.handleError(err))
+        );
+    }
+
+    getContentUrl(nodeId: string, attachment?: boolean): string {
+        return this.apiService.getInstance().content.getContentUrl(nodeId, attachment);
+    }
+
+    getNode(nodeId: string): Observable<NodeEntry> {
+        return from(this.apiService.getInstance().core.nodesApi.getNode(nodeId));
+    }
+
+    getDownload(downloadId: string): Observable<DownloadEntry> {
+        return from(this.apiService.getInstance().core.downloadsApi.getDownload(downloadId));
+    }
+
+    cancelDownload(downloadId: string) {
+        this.apiService.getInstance().core.downloadsApi.cancelDownload(downloadId);
+    }
+
+    private handleError(error: any) {
+        this.logService.error(error);
+        return throwError(error || 'Server error');
+    }
+}