fix(mac): allow display of package help file linked content 🍎

mac/Config/Config/PackageContentWebView.swift

@@ -13,6 +13,7 @@ import WebKit
 import KeymanSettings
 
 public struct PackageContentWebView: NSViewRepresentable {
+
   let packageFileUrl: URL
 
   // create the AppKit view instance
@@ -21,12 +22,18 @@ public struct PackageContentWebView: NSViewRepresentable {
 
     // Connect the delegate to catch link clicks
     webView.navigationDelegate = context.coordinator
-
+    
     return webView
   }
 
-  // update the view when SwiftUI state changes
+  /**
+   * update the view when SwiftUI state changes
+   */
   public func updateNSView(_ nsView: WKWebView, context: Context) {
+    // first update the parent in the coordinator so we know which
+    // package we are displaying content for
+    context.coordinator.parent = self
+
     let request = URLRequest(url: packageFileUrl)
 
     // only load the request if it's not already loading/loaded to prevent infinite loops
@@ -41,50 +48,73 @@ public struct PackageContentWebView: NSViewRepresentable {
    * Coordinator acts as the WKNavigationDelegate
    */
   public func makeCoordinator() -> Coordinator {
-    Coordinator()
+    Coordinator(self)
   }
 
-  /**
-   * If a url links to the web rather than locally, open it in the default browser
-   */
   @MainActor
   public class Coordinator: NSObject, WKNavigationDelegate {
+    var parent: PackageContentWebView
+
+    init(_ parent: PackageContentWebView) {
+      self.parent = parent
+    }
+
+    /**
+     * If a url links to the web rather than locally, open it in the default browser
+     * Must force load links in the package content that change the main frame
+     * because WKWebView's security sandbox will block loading of new pages
+     */
     public func webView(_ webView: WKWebView,
                         decidePolicyFor navigationAction: WKNavigationAction,
                         decisionHandler: @escaping @MainActor @Sendable (WKNavigationActionPolicy) -> Void) {
-
-      // if not url, cancel
+      
+      // if no url, cancel
       guard let url = navigationAction.request.url else {
         decisionHandler(.cancel)
         return
       }
 
       // if not user-activated, pass through, e.g. for redirects
       guard navigationAction.navigationType == .linkActivated else {
-          decisionHandler(.allow)
-          return
+        print("url not user activated \(url.path())")
+        decisionHandler(.allow)
+        return
       }
-
-      // local files load in webview
+      
+      // load local files in webview, force-loading files that are in the same directory
       if url.isFileURL {
-          decisionHandler(.allow)
+        let standardizedIncomingUrl = url.standardizedFileURL
+        let packageDirectoryUrl = parent.packageFileUrl.deletingLastPathComponent()
+        let standardizedPackageDirectoryUrl = packageDirectoryUrl.standardizedFileURL
+
+        // check whether the file is from the current package
+        if standardizedIncomingUrl.path.hasPrefix(standardizedPackageDirectoryUrl.path) {
+          decisionHandler(.cancel) // Cancel regular navigation
+
+          // Force load with read permissions of package directory
+          webView.loadFileURL(standardizedIncomingUrl, allowingReadAccessTo: standardizedPackageDirectoryUrl)
           return
+        } else {
+          // block local files outside of your target directory, not sure how we would receive one
+          decisionHandler(.cancel)
+          return
+        }
       }
-
-      // handle external links by opening in web browser
+      
+      // not a file URL: handle external links by opening in web browser
       decisionHandler(.cancel)
-
+      
       var externalUrl = url
-
+      
       // strip "link:" prefix if present
       let urlString = url.absoluteString
       if urlString.hasPrefix("link:https://") || urlString.hasPrefix("link:http://") {
-          let cleanString = urlString.replacingOccurrences(of: "link:", with: "")
-          if let cleanUrl = URL(string: cleanString) {
-              externalUrl = cleanUrl
-          }
+        let cleanString = urlString.replacingOccurrences(of: "link:", with: "")
+        if let cleanUrl = URL(string: cleanString) {
+          externalUrl = cleanUrl
+        }
       }
-
+      
       // Open the external link in the default browser
       NSWorkspace.shared.open(externalUrl)
     }