Flush are rebuild web view queue when suspending and restoring the app. Issue #1563

iOS/Article/ArticleViewController.swift

@@ -75,6 +75,7 @@ class ArticleViewController: UIViewController {
 
 		NotificationCenter.default.addObserver(self, selector: #selector(unreadCountDidChange(_:)), name: .UnreadCountDidChange, object: nil)
 		NotificationCenter.default.addObserver(self, selector: #selector(statusesDidChange(_:)), name: .StatusesDidChange, object: nil)
+		NotificationCenter.default.addObserver(self, selector: #selector(contentSizeCategoryDidChange(_:)), name: UIContentSizeCategory.didChangeNotification, object: nil)
 		NotificationCenter.default.addObserver(self, selector: #selector(willEnterForeground(_:)), name: UIApplication.willEnterForegroundNotification, object: nil)
 
 		let fullScreenTapZone = UIView()
@@ -190,6 +191,15 @@ class ArticleViewController: UIViewController {
 		}
 	}
 
+	@objc func contentSizeCategoryDidChange(_ note: Notification) {
+		coordinator.webViewProvider.flushQueue()
+		coordinator.webViewProvider.replenishQueueIfNeeded()
+		if let controller = currentWebViewController {
+			controller.fullReload()
+			self.pageViewController.setViewControllers([controller], direction: .forward, animated: false, completion: nil)
+		}
+	}
+	
 	@objc func willEnterForeground(_ note: Notification) {
 		// The toolbar will come back on you if you don't hide it again
 		if AppDefaults.articleFullscreenEnabled {

iOS/Article/WebViewController.swift

@@ -89,7 +89,6 @@ class WebViewController: UIViewController {
 		NotificationCenter.default.addObserver(self, selector: #selector(webFeedIconDidBecomeAvailable(_:)), name: .WebFeedIconDidBecomeAvailable, object: nil)
 		NotificationCenter.default.addObserver(self, selector: #selector(avatarDidBecomeAvailable(_:)), name: .AvatarDidBecomeAvailable, object: nil)
 		NotificationCenter.default.addObserver(self, selector: #selector(faviconDidBecomeAvailable(_:)), name: .FaviconDidBecomeAvailable, object: nil)
-		NotificationCenter.default.addObserver(self, selector: #selector(contentSizeCategoryDidChange(_:)), name: UIContentSizeCategory.didChangeNotification, object: nil)
 		
 		// Configure the tap zones
 		configureTopShowBarsView()
@@ -118,10 +117,6 @@ class WebViewController: UIViewController {
 		reloadArticleImage()
 	}
 
-	@objc func contentSizeCategoryDidChange(_ note: Notification) {
-		fullReload()
-	}
-	
 	// MARK: Actions
 	
 	@objc func showBars(_ sender: Any) {
@@ -354,21 +349,6 @@ extension WebViewController: WKScriptMessageHandler {
 	
 }
 
-class WrapperScriptMessageHandler: NSObject, WKScriptMessageHandler {
-	
-	// We need to wrap a message handler to prevent a circlular reference
-	private weak var handler: WKScriptMessageHandler?
-	
-	init(_ handler: WKScriptMessageHandler) {
-		self.handler = handler
-	}
-	
-	func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
-		handler?.userContentController(userContentController, didReceive: message)
-	}
-	
-}
-
 // MARK: UIViewControllerTransitioningDelegate
 
 extension WebViewController: UIViewControllerTransitioningDelegate {

iOS/Article/WebViewProvider.swift

@@ -13,6 +13,10 @@ import WebKit
 /// Keep a queue of WebViews where we've already done a trivial load so that by the time we need them in the UI, they're past the flash-to-shite part of their lifecycle.
 class WebViewProvider: NSObject, WKNavigationDelegate {
 	
+	private struct MessageName {
+		static let domContentLoaded = "domContentLoaded"
+	}
+
 	let articleIconSchemeHandler: ArticleIconSchemeHandler
 	
 	private let minimumQueueDepth = 3
@@ -26,7 +30,31 @@ class WebViewProvider: NSObject, WKNavigationDelegate {
 		articleIconSchemeHandler = ArticleIconSchemeHandler(coordinator: coordinator)
 		super.init()
 		viewController.view.insertSubview(queue, at: 0)
+		
 		replenishQueueIfNeeded()
+		
+		NotificationCenter.default.addObserver(self, selector: #selector(didEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil)
+		NotificationCenter.default.addObserver(self, selector: #selector(willEnterForeground), name: UIApplication.willEnterForegroundNotification, object: nil)
+	}
+	
+	@objc func didEnterBackground() {
+		flushQueue()
+	}
+
+	@objc func willEnterForeground() {
+		replenishQueueIfNeeded()
+	}
+
+	func flushQueue() {
+		queue.subviews.forEach { $0.removeFromSuperview() }
+		waitingForFirstLoad = true
+	}
+
+	func replenishQueueIfNeeded() {
+		while queue.subviews.count < minimumQueueDepth {
+			let webView = WKWebView(frame: .zero, configuration: buildConfiguration())
+			enqueueWebView(webView)
+		}
 	}
 	
 	func dequeueWebView(completion: @escaping (WKWebView) -> ()) {
@@ -42,11 +70,10 @@ class WebViewProvider: NSObject, WKNavigationDelegate {
 			return
 		}
 
-		webView.navigationDelegate = self
+		webView.configuration.userContentController.add(WrapperScriptMessageHandler(self), name: MessageName.domContentLoaded)
 		queue.insertSubview(webView, at: 0)
 
 		webView.loadFileURL(ArticleRenderer.page.url, allowingReadAccessTo: ArticleRenderer.page.baseURL)
-
 	}
 
 	// MARK: WKNavigationDelegate
@@ -63,30 +90,39 @@ class WebViewProvider: NSObject, WKNavigationDelegate {
 		}
 	}
 	
-	// MARK: Private
+}
 
-	private func replenishQueueIfNeeded() {
-		while queue.subviews.count < minimumQueueDepth {
-			let preferences = WKPreferences()
-			preferences.javaScriptCanOpenWindowsAutomatically = false
-			preferences.javaScriptEnabled = true
+// MARK: WKScriptMessageHandler
 
-			let configuration = WKWebViewConfiguration()
-			configuration.preferences = preferences
-			configuration.setValue(true, forKey: "allowUniversalAccessFromFileURLs")
-			configuration.allowsInlineMediaPlayback = true
-			configuration.mediaTypesRequiringUserActionForPlayback = .video
-			configuration.setURLSchemeHandler(articleIconSchemeHandler, forURLScheme: ArticleRenderer.imageIconScheme)
-			
-			let webView = WKWebView(frame: .zero, configuration: configuration)
-			enqueueWebView(webView)
+extension WebViewProvider: WKScriptMessageHandler {
+
+	func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
+		switch message.name {
+		case MessageName.domContentLoaded:
+			if waitingForFirstLoad {
+				waitingForFirstLoad = false
+				if let completion = waitingCompletionHandler {
+					DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
+						self.completeRequest(completion: completion)
+						self.waitingCompletionHandler = nil
+					}
+				}
+			}
+		default:
+			return
 		}
 	}
 	
-	private func completeRequest(completion: @escaping (WKWebView) -> ()) {
+}
+
+// MARK: Private
+
+private extension WebViewProvider {
+	
+	func completeRequest(completion: @escaping (WKWebView) -> ()) {
 		if let webView = queue.subviews.last as? WKWebView {
 			webView.removeFromSuperview()
-			webView.navigationDelegate = nil
+			webView.configuration.userContentController.removeScriptMessageHandler(forName: MessageName.domContentLoaded)
 			replenishQueueIfNeeded()
 			completion(webView)
 			return
@@ -96,5 +132,19 @@ class WebViewProvider: NSObject, WKNavigationDelegate {
 		let webView = WKWebView(frame: .zero)
 		completion(webView)
 	}
-	
+
+	func buildConfiguration() -> WKWebViewConfiguration {
+		let preferences = WKPreferences()
+		preferences.javaScriptCanOpenWindowsAutomatically = false
+		preferences.javaScriptEnabled = true
+
+		let configuration = WKWebViewConfiguration()
+		configuration.preferences = preferences
+		configuration.setValue(true, forKey: "allowUniversalAccessFromFileURLs")
+		configuration.allowsInlineMediaPlayback = true
+		configuration.mediaTypesRequiringUserActionForPlayback = .video
+		configuration.setURLSchemeHandler(articleIconSchemeHandler, forURLScheme: ArticleRenderer.imageIconScheme)
+		
+		return configuration
+	}
 }

iOS/Article/WrapperScriptMessageHandler.swift

@@ -0,0 +1,25 @@
+//
+//  WrapperScriptMessageHandler.swift
+//  NetNewsWire-iOS
+//
+//  Created by Maurice Parker on 2/4/20.
+//  Copyright © 2020 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import WebKit
+
+class WrapperScriptMessageHandler: NSObject, WKScriptMessageHandler {
+	
+	// We need to wrap a message handler to prevent a circlular reference
+	private weak var handler: WKScriptMessageHandler?
+	
+	init(_ handler: WKScriptMessageHandler) {
+		self.handler = handler
+	}
+	
+	func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
+		handler?.userContentController(userContentController, didReceive: message)
+	}
+	
+}

iOS/Resources/main_ios.js

@@ -156,3 +156,7 @@ function stopMediaPlayback() {
 		element.pause();
 	});
 }
+
+window.addEventListener('DOMContentLoaded', (event) => {
+    window.webkit.messageHandlers.domContentLoaded.postMessage("");
+});