Fix file downloads from notebooks container (#196)

* Fix file downloads from notebooks container

* Add downloading message

src/Explorer/Explorer.ts

@@ -87,6 +87,7 @@ import { ContextualPaneBase } from "./Panes/ContextualPaneBase";
 import TabsBase from "./Tabs/TabsBase";
 import { CommandButtonComponentProps } from "./Controls/CommandButton/CommandButtonComponent";
 import { updateUserContext, userContext } from "../UserContext";
+import { stringToBlob } from "../Utils/BlobUtils";
 
 BindingHandlersRegisterer.registerBindingHandlers();
 // Hold a reference to ComponentRegisterer to prevent transpiler to ignore import
@@ -2621,9 +2622,11 @@ export default class Explorer {
       throw new Error(error);
     }
 
+    const clearMessage = NotificationConsoleUtils.logConsoleProgress(`Downloading ${notebookFile.path}`);
+
     return this.notebookManager?.notebookContentClient.readFileContent(notebookFile.path).then(
       (content: string) => {
-        const blob = new Blob([content], { type: "octet/stream" });
+        const blob = stringToBlob(content, "text/plain");
         if (navigator.msSaveBlob) {
           // for IE and Edge
           navigator.msSaveBlob(blob, notebookFile.name);
@@ -2640,12 +2643,16 @@ export default class Explorer {
           downloadLink.click();
           downloadLink.remove();
         }
+
+        clearMessage();
       },
       (error: any) => {
         NotificationConsoleUtils.logConsoleMessage(
           ConsoleDataType.Error,
           `Could not download notebook ${JSON.stringify(error)}`
         );
+
+        clearMessage();
       }
     );
   }

src/Explorer/Notebook/NotebookContentClient.ts

@@ -194,18 +194,24 @@ export class NotebookContentClient {
       });
   }
 
-  public readFileContent(filePath: string): Promise<string> {
-    const fileType = NotebookUtil.isNotebookFile(filePath) ? "notebook" : "file";
-    return this.contentProvider
-      .get(this.getServerConfig(), filePath, { type: fileType, format: "text", content: 1 })
-      .toPromise()
-      .then(xhr => {
+  public async readFileContent(filePath: string): Promise<string> {
+    const xhr = await this.contentProvider.get(this.getServerConfig(), filePath, { content: 1 }).toPromise();
     const content = (xhr.response as any).content;
     if (!content) {
       throw new Error("No content read");
     }
+
+    const format = (xhr.response as any).format;
+    switch (format) {
+      case "text":
+        return content;
+      case "base64":
+        return atob(content);
+      case "json":
         return stringifyNotebook(content);
-      });
+      default:
+        throw new Error(`Unsupported content format ${format}`);
+    }
   }
 
   private deleteNotebookFile(path: string): Promise<string> {

src/Utils/BlobUtils.ts

@@ -0,0 +1,17 @@
+export const stringToBlob = (data: string, contentType: string, sliceSize = 512): Blob => {
+  const byteArrays = [];
+
+  for (let offset = 0; offset < data.length; offset += sliceSize) {
+    const slice = data.slice(offset, offset + sliceSize);
+
+    const byteNumbers = new Array(slice.length);
+    for (let i = 0; i < slice.length; i++) {
+      byteNumbers[i] = slice.charCodeAt(i);
+    }
+
+    const byteArray = new Uint8Array(byteNumbers);
+    byteArrays.push(byteArray);
+  }
+
+  return new Blob(byteArrays, { type: contentType });
+};