[mattermost-communityGH-314] Persist and reapply users settings in ma…

…c app

Relates to: mattermost-community#314

.gitignore

@@ -56,6 +56,7 @@ focalboard*.db
 mac/resources/config.json
 mac/temp
 mac/dist
+mac/*.xcodeproj/**/xcuserdata
 linux/bin
 linux/dist
 linux/temp

mac/Focalboard/AppDelegate.swift

@@ -32,10 +32,8 @@ class AppDelegate: NSObject, NSApplicationDelegate {
 
 	@IBAction func openNewWindow(_ sender: Any?) {
 		let mainStoryBoard = NSStoryboard(name: "Main", bundle: nil)
-		let tabViewController = mainStoryBoard.instantiateController(withIdentifier: "ViewController") as? ViewController
 		let windowController = mainStoryBoard.instantiateController(withIdentifier: "WindowController") as! NSWindowController
 		windowController.showWindow(self)
-		windowController.contentViewController = tabViewController
 	}
 
 	private func showWhatsNewDialogIfNeeded() {

mac/Focalboard/ViewController.swift

@@ -4,10 +4,18 @@
 import Cocoa
 import WebKit
 
+private let messageHandlerName = "callback"
+
+private enum MessageType: String {
+    case didImportUserSettings
+	case didNotImportUserSettings
+}
+
 class ViewController:
 	NSViewController,
 	WKUIDelegate,
-	WKNavigationDelegate {
+	WKNavigationDelegate,
+	WKScriptMessageHandler {
 	@IBOutlet var webView: WKWebView!
 	private var refreshWebViewOnLoad = true
 
@@ -19,14 +27,15 @@ class ViewController:
 		webView.navigationDelegate = self
 		webView.uiDelegate = self
 		webView.isHidden = true
+		webView.configuration.userContentController.add(self, name: messageHandlerName)
 
 		clearWebViewCache()
 
 		// Load the home page if the server was started, otherwise wait until it has
 		let appDelegate = NSApplication.shared.delegate as! AppDelegate
 		if (appDelegate.isServerStarted) {
-			self.updateSessionToken()
-			self.loadHomepage()
+			updateSessionTokenAndUserSettings()
+			loadHomepage()
 		}
 
 		// Do any additional setup after loading the view.
@@ -38,6 +47,11 @@ class ViewController:
 		self.view.window?.makeFirstResponder(self.webView)
 	}
 
+    override func viewWillDisappear() {
+        super.viewWillDisappear()
+        persistUserSettings()
+    }
+
 	override var representedObject: Any? {
 		didSet {
 			// Update the view, if already loaded.
@@ -64,20 +78,70 @@ class ViewController:
 	@objc func onServerStarted() {
 		NSLog("onServerStarted")
 		DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
-			self.updateSessionToken()
+			self.updateSessionTokenAndUserSettings()
 			self.loadHomepage()
 		}
 	}
 
-	private func updateSessionToken() {
+	private func persistUserSettings() {
+		let semaphore = DispatchSemaphore(value: 0)
+
+		// Convert to base64 to avoid escaping issues when later inserting the exported settings into the import script
+		webView.evaluateJavaScript("window.btoa(Focalboard.exportUserSettings())") { result, error in
+			defer { semaphore.signal() }
+			guard let base64 = result as? String, let data = Data(base64Encoded: base64), let decoded = String(data: data, encoding: .utf8) else {
+				NSLog("Failed to export user settings: \(error?.localizedDescription ?? "?")")
+				return
+			}
+			UserDefaults.standard.set(base64, forKey: "localStorage")
+			NSLog("Persisted user settings: \(decoded)")
+		}
+
+		// During shutdown the system grants us about 5 seconds to clean up and store user data
+		let timeout = DispatchTime.now() + .seconds(3)
+		var result: DispatchTimeoutResult?
+
+		// Busy wait because evaluateJavaScript can only be called from *and* signals on the main thread
+		while (result != .success && .now() < timeout) {
+			result = semaphore.wait(timeout: .now())
+			RunLoop.current.run(mode: .default, before: Date())
+		}
+
+		if result == .timedOut {
+			NSLog("Timed out trying to persist user settings")
+		}
+	}
+
+	private func updateSessionTokenAndUserSettings() {
 		let appDelegate = NSApplication.shared.delegate as! AppDelegate
-		let script = WKUserScript(
+		let sessionTokenScript = WKUserScript(
 			source: "localStorage.setItem('focalboardSessionId', '\(appDelegate.sessionToken)');",
 			injectionTime: .atDocumentStart,
 			forMainFrameOnly: true
 		)
+		let base64 = UserDefaults.standard.string(forKey: "localStorage") ?? ""
+		let userSettingsScript = WKUserScript(
+			source: """
+				const settings = window.atob("\(base64)");
+				if (typeof(Focalboard) !== 'undefined') {
+					if (Focalboard.importUserSettings(settings)) {
+						window.webkit.messageHandlers.\(messageHandlerName).postMessage({
+							type: '\(MessageType.didImportUserSettings.rawValue)',
+							settings: settings
+						});
+					} else {
+						window.webkit.messageHandlers.\(messageHandlerName).postMessage({
+							type: '\(MessageType.didNotImportUserSettings.rawValue)'
+						});
+					}
+				}
+				""",
+			injectionTime: .atDocumentEnd,
+			forMainFrameOnly: true
+		)
 		webView.configuration.userContentController.removeAllUserScripts()
-		webView.configuration.userContentController.addUserScript(script)
+		webView.configuration.userContentController.addUserScript(sessionTokenScript)
+		webView.configuration.userContentController.addUserScript(userSettingsScript)
 	}
 
 	private func loadHomepage() {
@@ -219,5 +283,17 @@ class ViewController:
 	@IBAction func navigateToHome(_ sender: NSObject) {
 		loadHomepage()
 	}
+
+	func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
+		guard let body = message.body as? [String: Any], let rawType = body["type"] as? String, let type = MessageType(rawValue: rawType) else {
+			return
+		}
+		switch type {
+		case .didImportUserSettings:
+			NSLog("Imported user settings: \(body["settings"] ?? "?")")
+		case .didNotImportUserSettings:
+			NSLog("Skipped importing stale, empty or invalid user settings")
+		}
+	}
 }
 

webapp/src/userSettings.ts

@@ -0,0 +1,32 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+const keys = ['language', 'theme', 'lastBoardId', 'lastViewId', 'emoji-mart.last', 'emoji-mart.frequently']
+
+export function exportUserSettings(): string {
+    const settings = Object.fromEntries(keys.map((key) => [key, localStorage.getItem(key)]))
+    settings.timestamp = `${Date.now()}`
+    return JSON.stringify(settings)
+}
+
+export function importUserSettings(json: string): boolean {
+    const settings = parseUserSettings(json)
+    const timestamp = settings.timestamp
+    const lastTimestamp = localStorage.getItem('timestamp')
+    if (!timestamp || (lastTimestamp && Number(timestamp) <= Number(lastTimestamp))) {
+        return false
+    }
+    for (const [key, value] of Object.entries(settings)) {
+        localStorage.setItem(key, value as string)
+    }
+    location.reload()
+    return true
+}
+
+function parseUserSettings(json: string): any {
+    try {
+        return JSON.parse(json)
+    } catch (e) {
+        return {}
+    }
+}

webapp/webpack.common.js

@@ -92,10 +92,9 @@ function makeCommonConfig() {
                 publicPath: '{{.BaseURL}}/',
             }),
         ],
-        entry: {
-            main: './src/main.tsx',
-        },
+        entry: ['./src/main.tsx', './src/userSettings.ts'],
         output: {
+            library: "Focalboard",
             filename: 'static/[name].js',
             path: outpath,
         },