S3: remember last-used "Download As" directory #2971

Problem:
When downloading S3 files, the "Save As" dialog always defaults to the Downloads
directory.

Solution:
Store the last-used download path and use it for next save prompt.

ref #2855

Author: gsweetwood

.changes/next-release/Feature-8126fa07-73a4-49c6-bec5-de9034957ce8.json

@@ -0,0 +1,4 @@
+{
+	"type": "Feature",
+	"description": "S3: \"Download As\" action defaults to the last-used download path."
+}

src/s3/commands/downloadFileAs.ts

@@ -6,7 +6,7 @@
 import * as path from 'path'
 import * as vscode from 'vscode'
 
-import { downloadsDir } from '../../shared/filesystemUtilities'
+import { getDefaultDownloadPath, setDefaultDownloadPath } from '../../shared/filesystemUtilities'
 import { Window } from '../../shared/vscode/window'
 import { S3FileNode } from '../explorer/s3FileNode'
 import { readablePath } from '../util'
@@ -119,10 +119,13 @@ export async function downloadFileAsCommand(
     const sourcePath = readablePath(node)
 
     await telemetry.s3_downloadObject.run(async () => {
-        const saveLocation = await promptForSaveLocation(file.name, window)
+        const downloadPath = getDefaultDownloadPath()
+
+        const saveLocation = await promptForSaveLocation(file.name, window, downloadPath)
         if (!saveLocation) {
             throw new CancellationError('user')
         }
+        setDefaultDownloadPath(saveLocation.fsPath)
 
         showOutputMessage(`Downloading "${sourcePath}" to: ${saveLocation}`, outputChannel)
 
@@ -140,7 +143,11 @@ export async function downloadFileAsCommand(
     })
 }
 
-async function promptForSaveLocation(fileName: string, window: Window): Promise<vscode.Uri | undefined> {
+async function promptForSaveLocation(
+    fileName: string,
+    window: Window,
+    saveLocation: string
+): Promise<vscode.Uri | undefined> {
     const extension = path.extname(fileName)
 
     // Insertion order matters, as it determines the ordering in the filters dropdown
@@ -149,7 +156,7 @@ async function promptForSaveLocation(fileName: string, window: Window): Promise<
         ? { [`*${extension}`]: [extension.slice(1)], 'All Files': ['*'] }
         : { 'All Files': ['*'] }
 
-    const downloadPath = path.join(downloadsDir(), fileName)
+    const downloadPath = path.join(saveLocation, fileName)
     return window.showSaveDialog({
         defaultUri: vscode.Uri.file(downloadPath),
         saveLabel: localize('AWS.s3.downloadFile.saveButton', 'Download'),

src/shared/filesystemUtilities.ts

@@ -12,6 +12,7 @@ import * as path from 'path'
 import * as vscode from 'vscode'
 import { getLogger } from './logger'
 import * as pathutils from './utilities/pathUtils'
+import globals from '../shared/extensionGlobals'
 
 const DEFAULT_ENCODING: BufferEncoding = 'utf8'
 
@@ -224,3 +225,29 @@ export async function cloud9Findfile(dir: string, fileName: string): Promise<vsc
     }
     return []
 }
+/**
+ * @returns  A string path to the last locally stored download location. If none, returns the users 'Downloads' directory path.
+ */
+export function getDefaultDownloadPath(): string {
+    const lastUsedPath = globals.context.globalState.get('aws.downloadPath')
+    if (lastUsedPath) {
+        if (typeof lastUsedPath === 'string') {
+            return lastUsedPath
+        }
+        getLogger().error('Expected "aws.downloadPath" to be string, got %O', typeof lastUsedPath)
+    }
+    return downloadsDir()
+}
+
+export async function setDefaultDownloadPath(downloadPath: string) {
+    try {
+        const savePath = await stat(downloadPath)
+        if (savePath.isDirectory()) {
+            globals.context.globalState.update('aws.downloadPath', downloadPath)
+        } else {
+            globals.context.globalState.update('aws.downloadPath', path.dirname(downloadPath))
+        }
+    } catch (err) {
+        getLogger().error('Error while setting "aws.downloadPath"', err as Error)
+    }
+}

src/test/s3/commands/downloadFileAs.test.ts

@@ -16,6 +16,8 @@ import { MockOutputChannel } from '../../mockOutputChannel'
 import { FakeWindow } from '../../shared/vscode/fakeWindow'
 import { anything, mock, instance, when, verify } from '../../utilities/mockito'
 import { makeTemporaryToolkitFolder } from '../../../shared/filesystemUtilities'
+import globals from '../../../shared/extensionGlobals'
+import { assertEqualPaths } from '../../testUtil'
 
 describe('downloadFileAsCommand', function () {
     const bucketName = 'bucket-name'
@@ -52,12 +54,15 @@ describe('downloadFileAsCommand', function () {
     it('prompts for save location, downloads file with progress, and shows output channel', async function () {
         const window = new FakeWindow({ dialog: { saveSelection: saveLocation } })
         const outputChannel = new MockOutputChannel()
+        globals.context.globalState.update('aws.downloadPath', temp)
 
         when(s3.downloadFileStream(anything(), anything())).thenResolve(bufferToStream(Buffer.alloc(16)))
 
         await downloadFileAsCommand(node, window, outputChannel)
 
-        assert.ok(window.dialog.saveOptions?.defaultUri?.path?.endsWith(fileName))
+        assert.ok(window.dialog.saveOptions?.defaultUri?.fsPath)
+        assertEqualPaths(window.dialog.saveOptions.defaultUri.fsPath, path.join(temp, 'file.jpg'))
+
         assert.strictEqual(window.dialog.saveOptions?.saveLabel, 'Download')
         assert.deepStrictEqual(window.dialog.saveOptions?.filters, { 'All Files': ['*'], '*.jpg': ['jpg'] })