GLSP-77: Allow WebSocket connections to reconnect after interrupt (#208)

* GLSP-77: Allow WebSocket connections to reconnect after interrupt If Websocket connections reconnect after an interrupt, ensure that the last modelState is restored on RequestModelAction if available Part of eclipse-glsp/glsp#77
eclipse-glsp · Jul 24, 2023 · 8587e82 · 8587e82
1 parent 355cb4d
commit 8587e82
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Showing 2 changed files with 29 additions and 4 deletions.
diff --git a/...lsp.server/src/org/eclipse/glsp/server/features/core/model/RequestModelActionHandler.java b/...lsp.server/src/org/eclipse/glsp/server/features/core/model/RequestModelActionHandler.java
@@ -18,6 +18,7 @@
 import java.util.List;
 import java.util.Optional;
 
+import org.eclipse.glsp.graph.GModelRoot;
 import org.eclipse.glsp.server.actions.AbstractActionHandler;
 import org.eclipse.glsp.server.actions.Action;
 import org.eclipse.glsp.server.actions.ActionDispatcher;
@@ -26,6 +27,7 @@
 import org.eclipse.glsp.server.features.progress.ProgressService;
 import org.eclipse.glsp.server.features.sourcemodelwatcher.SourceModelWatcher;
 import org.eclipse.glsp.server.model.GModelState;
+import org.eclipse.glsp.server.utils.ClientOptionsUtil;
 import org.eclipse.glsp.server.utils.ServerStatusUtil;
 
 import com.google.inject.Inject;
@@ -64,15 +66,34 @@ public class RequestModelActionHandler extends AbstractActionHandler<RequestMode
    public List<Action> executeAction(final RequestModelAction action) {
       modelState.setClientOptions(action.getOptions());
 
+      boolean isReconnecting = ClientOptionsUtil.isReconnecting(action.getOptions());
+
       ProgressMonitor monitor = notifyStartLoading();
-      sourceModelStorage.loadSourceModel(action);
+      if (isReconnecting) {
+         handleReconnect(action);
+      } else {
+         sourceModelStorage.loadSourceModel(action);
+      }
       notifyFinishedLoading(monitor);
 
-      sourceModelWatcher.ifPresent(watcher -> watcher.startWatching());
+      if (!isReconnecting) {
+         sourceModelWatcher.ifPresent(watcher -> watcher.startWatching());
+      }
 
       return modelSubmissionHandler.submitModel();
    }
 
+   protected void handleReconnect(final RequestModelAction action) {
+      GModelRoot oldModel = modelState.getRoot();
+      if (oldModel != null) {
+         // decrease revision by one, as each submit will increase it by one;
+         // the next save would produce warning that source model was changed otherwise
+         modelState.getRoot().setRevision(oldModel.getRevision() - 1);
+      } else {
+         sourceModelStorage.loadSourceModel(action);
+      }
+   }
+
    protected ProgressMonitor notifyStartLoading() {
       String message = "Model loading in progress";
       actionDispatcher.dispatch(ServerStatusUtil.info(message));

diff --git a/plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/utils/ClientOptionsUtil.java b/plugins/org.eclipse.glsp.server/src/org/eclipse/glsp/server/utils/ClientOptionsUtil.java
@@ -1,5 +1,5 @@
 /********************************************************************************
- * Copyright (c) 2019-2021 EclipseSource and others.
+ * Copyright (c) 2019-2023 EclipseSource and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -25,6 +25,7 @@
 public final class ClientOptionsUtil {
    public static final String DIAGRAM_TYPE = "diagramType";
    public static final String SOURCE_URI = "sourceUri";
+   public static final String IS_RECONNECTING = "isReconnecting";
    private static final String FILE_PREFIX = "file://";
 
    private ClientOptionsUtil() {}
@@ -35,13 +36,16 @@ public static Optional<String> getSourceUri(final Map<String, String> options) {
 
    public static Optional<String> getDiagramType(final Map<String, String> options) {
       return MapUtil.getValue(options, DIAGRAM_TYPE);
-
    }
 
    public static Optional<File> getSourceUriAsFile(final Map<String, String> options) {
       return MapUtil.getValue(options, SOURCE_URI).map(ClientOptionsUtil::getAsFile);
    }
 
+   public static Boolean isReconnecting(final Map<String, String> options) {
+      return MapUtil.getBoolValue(options, IS_RECONNECTING);
+   }
+
    public static String adaptUri(final String uri) {
       return uri.replace(FILE_PREFIX, "");
    }