PY-30468 reST preview: open external browser when clicking on the link

python/rest/src/com/jetbrains/rest/editor/RestJavaFxHtmlPanel.java

@@ -1,12 +1,25 @@
 // Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.jetbrains.rest.editor;
 
+import com.intellij.ide.BrowserUtil;
 import com.intellij.ide.ui.LafManager;
 import com.intellij.ide.ui.LafManagerListener;
 import com.intellij.ide.ui.laf.darcula.DarculaLookAndFeelInfo;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.ui.javafx.JavaFxHtmlPanel;
+import javafx.beans.value.ChangeListener;
+import javafx.beans.value.ObservableValue;
+import javafx.concurrent.Worker;
 import javafx.scene.text.FontSmoothingType;
+import javafx.scene.web.WebEngine;
 import javafx.scene.web.WebView;
+import org.jetbrains.annotations.NotNull;
+import org.w3c.dom.Document;
+import org.w3c.dom.NodeList;
+import org.w3c.dom.events.Event;
+import org.w3c.dom.events.EventListener;
+import org.w3c.dom.events.EventTarget;
+import org.w3c.dom.html.HTMLAnchorElement;
 
 import java.net.URL;
 
@@ -18,6 +31,8 @@ public class RestJavaFxHtmlPanel extends JavaFxHtmlPanel implements RestPreviewP
     runInPlatformWhenAvailable(() -> {
       final WebView webView = getWebViewGuaranteed();
       webView.fontSmoothingTypeProperty().setValue(FontSmoothingType.LCD);
+
+      webView.getEngine().getLoadWorker().stateProperty().addListener(new HyperlinkRedirectListener(webView));
       updateLaf(LafManager.getInstance().getCurrentLookAndFeel() instanceof DarculaLookAndFeelInfo);
     });
   }
@@ -34,9 +49,52 @@ public class RestJavaFxHtmlPanel extends JavaFxHtmlPanel implements RestPreviewP
   }
 
   private void updateLaf(boolean isDarcula) {
-    runInPlatformWhenAvailable(() -> {
-      final WebView webView = getWebViewGuaranteed();
-      webView.getEngine().setUserStyleSheetLocation(getStyle(isDarcula).toExternalForm());
-    });
+    ApplicationManager.getApplication().invokeLater(() ->
+      runInPlatformWhenAvailable(() -> {
+        final WebView webView = getWebViewGuaranteed();
+        webView.getEngine().setUserStyleSheetLocation(getStyle(isDarcula).toExternalForm());
+      }
+    ));
+  }
+
+  private static class HyperlinkRedirectListener implements ChangeListener<Worker.State>{
+    private static final String EVENT_TYPE_CLICK = "click";
+    private final WebEngine myEngine;
+
+    public HyperlinkRedirectListener(WebView view) {
+      myEngine = view.getEngine();
+    }
+
+    @Override
+    public void changed(ObservableValue<? extends Worker.State> observable, Worker.State oldValue, Worker.State newValue) {
+      if (newValue == Worker.State.SUCCEEDED) {
+        final EventListener listener = makeHyperLinkListener();
+        addListenerToAllHyperlinkItems(listener);
+      }
+    }
+    private void addListenerToAllHyperlinkItems(EventListener listener) {
+      final Document doc = myEngine.getDocument();
+      if (doc != null) {
+        final NodeList nodeList = doc.getElementsByTagName("a");
+        for (int i = 0; i < nodeList.getLength(); i++) {
+          ((EventTarget)nodeList.item(i)).addEventListener(EVENT_TYPE_CLICK, listener, false);
+        }
+      }
+    }
+
+    @NotNull
+    private static EventListener makeHyperLinkListener() {
+      return new EventListener() {
+        @Override
+        public void handleEvent(Event ev) {
+          EventTarget target = ev.getCurrentTarget();
+          HTMLAnchorElement anchorElement = (HTMLAnchorElement) target;
+          String href = anchorElement.getHref();
+          if (href == null) return;
+          BrowserUtil.browse(href);
+          ev.preventDefault();
+        }
+      };
+    }
   }
 }