How to dispatch Action from File Menu to Java server without the Diagram Module

[amiths89]

I am tryin to dispatch an action from a Command Contribution created on the client side which basically creates a new resource file in the workspace. Now I have a handler on the Java server side but since this is not related to the diagram am not sure how to bind this Action handler.
I have a Menu contribution and command contribution bound in the front end that dispatches the action and then an Action and Action handler on the Java server side as well. The below code is the Command contribution. I need this to dispatch the action handler in the Java server. But it does not seem to be triggering the action.
constructor(@inject(TYPES.IActionDispatcher) protected actionDispatcher: GLSPActionDispatcher) {} registerCommands(registry: CommandRegistry): void { registry.registerCommand(startUserProgramCommand, { execute: () => { this.actionDispatcher?.dispatch(CreatNewProjectOperation.create()); } });

[planger]

I assume, you are talking about a Theia command contribution in the Theia integration, is that right?

If yes, I recommend registering the Theia command as you did, but use the GLSPCommandHandler instead of a direct handler (execute: () => {...}).

With the GLSPCommandHandler, you get access to the GLSP diagram editor context and just return GLSP actions to be invoked as a result of the Theia command. Please see the workflow diagram for an example.

@injectable()
export class WorkflowTaskEditCommandContribution implements CommandContribution {
    @inject(ApplicationShell) protected readonly shell: ApplicationShell;
    registerCommands(commands: CommandRegistry): void {
        commands.registerCommand(
            { id: WorkflowTaskEditingCommands.EDIT_TASK, label: 'Direct Edit Task' },
            new GLSPCommandHandler(this.shell, {
                actions: context => /* the array of actions to be invoked by this command */ [
                    SetUIExtensionVisibilityAction.create({
                        extensionId: TaskEditor.ID,
                        visible: true,
                        contextElementsId: [context.selectedElements[0].id]
                    })
                ],
                isEnabled: context => !context.isReadonly && context.selectedElements.filter(isTaskNode).length === 1
            })
        );
    }
}

If the server registers an action handler for the action, you invoke in your command, the action will be forwarded to the server automatically and your handler on the server will be executed accordingly.

[amiths89]

@planger Actually I wanted to look from outside GLSP diagram completely without touching the diagrams at all. This has to do with creating the diagram files(XML content) and other resource files so you see I dont want to open the diagram as am trying to populate the content of the diagram files before it being open. At the moment I am overriding the loadResource in the Java server to populate the contents of the diagram files which triggers when i try to open the diagram but this is only a temporary solution as I would need to work on more actions from the Theia Menu that would not need to touch the diagrams. I am currently trying to figure out the json rpc messages being sent to trigger the actions. What would i need to do if i wanted to trigger actions bypassing the diagrams completely?

[planger]

If you want to add commands and menu items in Theia that don't touch the diagram-related aspects, e.g. creating a new file with a certain content, you can just use plain Theia commands. There is nothing specific to GLSP then, and thus no GLSPCommandHandler involved.

Only if you want to trigger a Theia command that impacts a running diagram instance you probably need GLSPCommandHandler for that.

[amiths89]

I understand this is not the way GLSP works but if i were to explore this I wanted a hint of a direction where I should be looking at in order to be in a position to run my Java code that is outside the diagram.

So my file editing code which is in Java are all sitting in the glsp-server, I have a Theia Command in glsp-client that promts the user to enter a project name which then creates a folder and an empty diagram file and then using that file path I need to be able run the Java code that is currently in the glsp-server which edits the contents of the file.

[tortmayr]

You should be able to make this work with a little bit of customization.

In order to communicate with the GLSP server you need to use the GLSPClient. If you want to retrieve the client ouside of the context of an active diagram you can use the DiagramServiceProvider.

So in your custom command contribution, you can inject the DiagramServiceProvider and retrieve the GLSPClient for your contributionId, then send the action message. Here is a snippet of a potential implementation:

@injectable()
export class MyCommandContribution implements CommandContribution {
    @inject(DiagramServiceProvider)
    protected diagramServiceProvider: DiagramServiceProvider;

    protected clientContribution: GLSPClientContribution;

    @postConstruct()
    protected init(): void {
        this.clientContribution = this.diagramServiceProvider.getGLSPClientContribution('yourContributionId');
    }

    registerCommands(commands: CommandRegistry): void {
        commands.registerCommand(startUserProgramCommand, {
            execute: async () => {
                const glspClient = await this.clientContribution.glspClient;
                glspClient.sendActionMessage({ clientId: 'no-session', action: CreateNewProjectAction.create() });
            }
        });
    }
}

Then on the server side you need a custom GLSPServer implementation, because the default implementation will faill if it receives an action that is not associated with a diagram id. For this you need to override the process method:

public class MyServer extends DefaultGLSPServer {

   @Override
   public void process(final ActionMessage message) {
      validateServerInitialized();
      if (message.getClientId().equals("no-session")) {
         this.handleSessionLessAction(message.getAction());
         return;
      }
      super.process(message);
   }

   protected void handleSessionLessAction(final Action action) {
      if (action instanceof CreateNewProjectAction) {
         // your custom handling
      }
   }
}

and create a custom server module:

public class MyServerModule extends ServerModule {

   @Override
   protected Class<? extends GLSPServer> bindGLSPServer() {
      return MyServer.class;
   }
}

and then use this new custom server module instead of the default one in your main/launch class.

I believe this approach should work, but I have not tested it.

[amiths89]

oh yes this is exactly what I was looking for. This will get me started. Thanks @tortmayr and @planger.

[amiths89]

I tried this solution and it worked perfectly fine and am able to trigger actions without opening the diagrams. Additional to this solution I only had to bind it to the diagram in the server side I guess it was looking for the module associated to the contribution ID. Thanks again @planger & @tortmayr