tutorial 02: Front-end Basics

The basics of controlling the magnetron.app front-end

In this tutorial you will learn to:

  • Set progress and main displayed message
  • Use a timed delay
  • Check if the user has pressed cancel
  • Abort the process
  • Quit the application

To begin, create a new recipe as you did in Tutorial 01 - Hello World.

It is important to keep the user informed while using the recipe, so instead of using the echo function echo("hello world"); from the first tutorial, you can use the setProgress() and setMainMessage() functions. To set the progress bar to 50%, you can use setProgress(50);, and to display a status message to the user, you can us setMainMessage("waiting for cancel action");

To give the user time to cancel the process, you can use the sleepMs function to add a delay. In this example, you can add the line 'sleepMs(5000);' to give the user 5 seconds to cancel the process.

To check if the user has opted to cancel the process, you can use the if( isCanceled() )method. If the user has canceled the process, you can use the abort function to stop any further execution of the script by adding


Or use the quit("quitting"); function to fully shutdown the application instead. You can include a message with either function, which will be echoed to the log and dialog.


To finish the process, you can set the progress bar to 100% using setProgress(100); and set the main message to "stopped normally" using setMainMessage("stopped normally");

Now you can run the recipe using (Ctrl/Cmd + Shift + S) and hit cancel to try out the functionality. Great work, you now know how to use the core app interactions!

The complete function:

function main()

    setMainMessage("waiting for cancel action");

    if ( isCanceled() )

    setMainMessage("stopped normally");