Fix #2333. Handle export in Mac App

mac/Focalboard.xcodeproj/project.pbxproj

@@ -9,6 +9,7 @@
 /* Begin PBXBuildFile section */
 		8014951C261598D600A51700 /* PortUtils.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8014951B261598D600A51700 /* PortUtils.swift */; };
 		804E57FC27441B6B008526F0 /* whatsnew.txt in Resources */ = {isa = PBXBuildFile; fileRef = 804E57FB27441B6B008526F0 /* whatsnew.txt */; };
+		80672A8B27BAFEBA00257B8C /* DownloadHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80672A8A27BAFEBA00257B8C /* DownloadHandler.swift */; };
 		80D6DEBB252E13CB00AEED9E /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80D6DEBA252E13CB00AEED9E /* AppDelegate.swift */; };
 		80D6DEBD252E13CB00AEED9E /* ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 80D6DEBC252E13CB00AEED9E /* ViewController.swift */; };
 		80D6DEBF252E13CD00AEED9E /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 80D6DEBE252E13CD00AEED9E /* Assets.xcassets */; };
@@ -42,6 +43,7 @@
 /* Begin PBXFileReference section */
 		8014951B261598D600A51700 /* PortUtils.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PortUtils.swift; sourceTree = "<group>"; };
 		804E57FB27441B6B008526F0 /* whatsnew.txt */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = whatsnew.txt; sourceTree = "<group>"; };
+		80672A8A27BAFEBA00257B8C /* DownloadHandler.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DownloadHandler.swift; sourceTree = "<group>"; };
 		80D6DEB7252E13CB00AEED9E /* Focalboard.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Focalboard.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		80D6DEBA252E13CB00AEED9E /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		80D6DEBC252E13CB00AEED9E /* ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewController.swift; sourceTree = "<group>"; };
@@ -116,6 +118,7 @@
 				80F8BF572624EB0C00FF3943 /* Globals.swift */,
 				8014951B261598D600A51700 /* PortUtils.swift */,
 				80D6DEBC252E13CB00AEED9E /* ViewController.swift */,
+				80672A8A27BAFEBA00257B8C /* DownloadHandler.swift */,
 				80F174B62788C1A2000A9EEA /* CustomWKWebView.swift */,
 				80F8BF4F2624E1BB00FF3943 /* WhatsNewViewController.swift */,
 				804E57FB27441B6B008526F0 /* whatsnew.txt */,
@@ -303,6 +306,7 @@
 				80F8BF502624E1BB00FF3943 /* WhatsNewViewController.swift in Sources */,
 				80F174B72788C1A2000A9EEA /* CustomWKWebView.swift in Sources */,
 				80F8BF582624EB0C00FF3943 /* Globals.swift in Sources */,
+				80672A8B27BAFEBA00257B8C /* DownloadHandler.swift in Sources */,
 				80D6DF18252F9BDE00AEED9E /* AutoSaveWindowController.swift in Sources */,
 				80D6DEBD252E13CB00AEED9E /* ViewController.swift in Sources */,
 				80D6DEBB252E13CB00AEED9E /* AppDelegate.swift in Sources */,
@@ -403,7 +407,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				MACOSX_DEPLOYMENT_TARGET = 10.14;
+				MACOSX_DEPLOYMENT_TARGET = 11.3;
 				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
 				MTL_FAST_MATH = YES;
 				ONLY_ACTIVE_ARCH = YES;
@@ -458,7 +462,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				MACOSX_DEPLOYMENT_TARGET = 10.14;
+				MACOSX_DEPLOYMENT_TARGET = 11.3;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				MTL_FAST_MATH = YES;
 				SDKROOT = macosx;

mac/Focalboard/DownloadHandler.swift

@@ -0,0 +1,40 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import Foundation
+import WebKit
+
+class DownloadHandler: NSObject, WKDownloadDelegate {
+	func download(_ download: WKDownload, decideDestinationUsing response: URLResponse, suggestedFilename: String, completionHandler: @escaping (URL?) -> Void) {
+		DispatchQueue.main.async {
+			// Let user select location of file
+			let savePanel = NSSavePanel()
+			savePanel.canCreateDirectories = true
+			savePanel.nameFieldStringValue = suggestedFilename
+			// BUGBUG: Specifying the allowedFileTypes causes Catalina to hang / error out
+			//savePanel.allowedFileTypes = [".boardsarchive"]
+			savePanel.begin { (result) in
+				if result.rawValue == NSApplication.ModalResponse.OK.rawValue,
+				   let fileUrl = savePanel.url {
+					if (FileManager.default.fileExists(atPath: fileUrl.path)) {
+						// HACKHACK: WKWebView doesn't appear to overwrite files, so delete exsiting files first
+						do {
+							try FileManager.default.removeItem(at: fileUrl)
+						} catch {
+							let alert = NSAlert()
+							alert.messageText = "Unable to replace \(fileUrl.path)"
+							alert.addButton(withTitle: "OK")
+							alert.alertStyle = .warning
+							alert.runModal()
+						}
+					}
+					completionHandler(fileUrl)
+				}
+			}
+		}
+	}
+
+	func downloadDidFinish(_ download: WKDownload) {
+		NSLog("downloadDidFinish")
+	}
+}

mac/Focalboard/ViewController.swift

@@ -12,6 +12,7 @@ class ViewController:
 	@IBOutlet var webView: CustomWKWebView!
 	private var didLoad = false
 	private var refreshWebViewOnLoad = true
+	private let downloadHandler = DownloadHandler()
 
 	override func viewDidLoad() {
 		super.viewDidLoad()
@@ -100,60 +101,6 @@ class ViewController:
 		webView.load(request)
 	}
 
-	private func downloadJsonUrl(_ url: URL) {
-		NSLog("downloadJsonUrl")
-		let prefix = "data:text/json,"
-		let urlString = url.absoluteString
-		let encodedJson = String(urlString[urlString.index(urlString.startIndex, offsetBy: prefix.lengthOfBytes(using: .utf8))...])
-		guard let json = encodedJson.removingPercentEncoding else {
-			return
-		}
-
-		// Form file name
-		let dateFormatter = DateFormatter()
-		dateFormatter.dateFormat = "yyyy-M-d"
-		let dateString = dateFormatter.string(from: Date())
-		let filename = "archive-\(dateString).focalboard"
-
-		// Save file
-		let savePanel = NSSavePanel()
-		savePanel.canCreateDirectories = true
-		savePanel.nameFieldStringValue = filename
-		// BUGBUG: Specifying the allowedFileTypes causes Catalina to hang / error out
-		//savePanel.allowedFileTypes = [".focalboard"]
-		savePanel.begin { (result) in
-			if result.rawValue == NSApplication.ModalResponse.OK.rawValue,
-			   let fileUrl = savePanel.url {
-				try? json.write(to: fileUrl, atomically: true, encoding: .utf8)
-			}
-		}
-	}
-
-	private func downloadCsvUrl(_ url: URL) {
-		NSLog("downloadCsvUrl")
-		let prefix = "data:text/csv;charset=utf-8,"
-		let urlString = url.absoluteString
-		let encodedContents = String(urlString[urlString.index(urlString.startIndex, offsetBy: prefix.lengthOfBytes(using: .utf8))...])
-		guard let contents = encodedContents.removingPercentEncoding else {
-			return
-		}
-
-		let filename = "data.csv"
-
-		// Save file
-		let savePanel = NSSavePanel()
-		savePanel.canCreateDirectories = true
-		savePanel.nameFieldStringValue = filename
-		// BUGBUG: Specifying the allowedFileTypes causes Catalina to hang / error out
-		//savePanel.allowedFileTypes = [".focalboard"]
-		savePanel.begin { (result) in
-			if result.rawValue == NSApplication.ModalResponse.OK.rawValue,
-			   let fileUrl = savePanel.url {
-				try? contents.write(to: fileUrl, atomically: true, encoding: .utf8)
-			}
-		}
-	}
-
 	func webView(_ webView: WKWebView, runOpenPanelWith parameters: WKOpenPanelParameters, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping ([URL]?) -> Void) {
 		NSLog("webView runOpenPanel")
 		let openPanel = NSOpenPanel()
@@ -169,22 +116,30 @@ class ViewController:
 		}
 	}
 
-	func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
-		if let url = navigationAction.request.url {
-			// Intercept archive downloads, and present native UI
-			if (url.absoluteString.hasPrefix("data:text/json,")) {
-				decisionHandler(.cancel)
-				downloadJsonUrl(url)
-				return
-			}
-			if (url.absoluteString.hasPrefix("data:text/csv;charset=utf-8,")) {
-				decisionHandler(.cancel)
-				downloadCsvUrl(url)
-				return
-			}
-			NSLog("decidePolicyFor navigationAction: \(url.absoluteString)")
+	// Handle downloads
+
+	func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, preferences: WKWebpagePreferences, decisionHandler: @escaping (WKNavigationActionPolicy, WKWebpagePreferences) -> Void) {
+		if navigationAction.shouldPerformDownload {
+			decisionHandler(.download, preferences)
+		} else {
+			decisionHandler(.allow, preferences)
 		}
-		decisionHandler(.allow)
+	}
+
+	func webView(_ webView: WKWebView, decidePolicyFor navigationResponse: WKNavigationResponse, decisionHandler: @escaping (WKNavigationResponsePolicy) -> Void) {
+		if navigationResponse.canShowMIMEType {
+			decisionHandler(.allow)
+		} else {
+			decisionHandler(.download)
+		}
+	}
+
+	func webView(_ webView: WKWebView, navigationAction: WKNavigationAction, didBecome download: WKDownload) {
+		download.delegate = downloadHandler
+	}
+
+	func webView(_ webView: WKWebView, navigationResponse: WKNavigationResponse, didBecome download: WKDownload) {
+		download.delegate = downloadHandler
 	}
 
 	func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {