Webserver

To serve the trigger interface, we spin up a local webserver by Express on startup.

note

The interface project is a React interface that is compiled in the public folder of the main process. Therefore, the interface can be served here.

Express Module

The express.ts file is a module responsible for initializing and managing the Express.js server process within the Kweenb application. It provides functionality to start the Express server and handle its lifecycle, particularly in the context of the application's environment (development or production).

This module defines functions to start and terminate the Express server process. It utilizes Node.js's child process capabilities to run the server in a separate node process, allowing better isolation and management of the server and main application logic.

Functions

killExpress

export const killExpress = () => {
  if (expressProcess && !expressProcess.killed) {
    expressProcess.kill("SIGINT");
  }
};

Kills the currently running Express server process if it is active.

initExpress

export const initExpress = (): ChildProcess | null => {
  const serverUrl =
    import.meta.env.MODE === "production"
      ? path.resolve(__dirname, "server.js")
      : path.resolve(__dirname, "../public/server.js");

  expressProcess = fork(serverUrl, {
    env: {
      ...process.env,
    },
  });

  try {
    if (expressProcess) {
      expressProcess.stdout?.on("data", console.log);
      expressProcess.stderr?.on("data", console.error);
    }
    return expressProcess;
  } catch (e) {
    return null;
  }
};

Initializes and starts the Express server process.

Details:

• Determines the correct server script to run based on the environment (production or development).
• Uses fork to start the server process with the determined server script.
• Sets up event listeners on the stdout and stderr streams of the process to log output and errors.
• Handles potential errors by returning null if the process cannot be started.