Listen for Connection Changes

Introduction

This how-to describes how to create a simple menu that displays a message box when the connection changes.

Prerequisites

Before starting this how-to, make sure you have completed the following prerequisites:

• This how-to uses the results of Get Started with the Web Extensibility API. Complete that how-to before starting this one.
• Familiarize yourself with creating menus as described in Create a Menu Using Web API and message boxes as described in Show a Message Box Using Web API.
• Your app must be running locally in Studio Pro to use the Runtime Controller API.

Listening for Connection Changes

You can listen for runtime connection state changes to know when the app starts or stops running. To do this, follow the steps below:

1. Add an event listener to respond when the connection state changes.
2. Replace the content of your src/main/index.ts file with the following:

import { IComponent, getStudioProApi } from "@mendix/extensions-api";

export const component: IComponent = {
    async loaded(componentContext) {
        const studioPro = getStudioProApi(componentContext);
        const runtimeControllerApi = studioPro.runtime.controller;
        const messageBoxApi = studioPro.ui.messageBoxes;

        // Listen for connection state changes
        runtimeControllerApi.addEventListener("connectionChanged", (args) => {
            messageBoxApi.show(
                "info",
                `Runtime connection: ${args.isConnected ? "Connected" : "Disconnected"}`
            );
        });
    }
};

The code uses:

• menuApi from studioPro.ui.extensionsMenu to use the menu API
• messageBoxApi from studioPro.ui.messageBoxes to show a dialog
• runtimeControllerApi from studioPro.runtime.controller to check if the connection changed

The connectionChanged event returns an object with:

• isConnected – a boolean indicating whether the runtime is currently connected (true) or disconnected (false)

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