Task development

Developing a scheduler task is as simple as creating a PHP file or MODX snippet. Add it to Scheduler when you need it. This document covers a few things that may be familiar if you develop for MODX.

File, snippet or processor?

First decide whether your task will be file-based, snippet-based, or reuse a processor. File tasks can live in version control; snippets are easier to edit in the Manager and can be reused on the frontend; processors are class-based and suit more complex logic. In all cases the task can do the same thing and the code you write is similar.

Passing data to the task

The component API lets you pass a $data array for run-time data that will be passed to the file or snippet. In the file or snippet these are available in $scriptProperties; we recommend using $modx->getOption to read them.

Logging errors in Scheduler

If something goes wrong in your file/snippet (e.g. a required variable is missing), you can log errors back to the scheduler. Adding an error also marks the run as failed. Example:

$run->addError('random_error', array(
    'random_number' => rand(0, 99999)
));

This logs an error in the scheduler of type "random_error" with the random number as extra data, and marks the run as failed.

Returning a result

Return a string (e.g. JSON or plain HTML if you prefer); it will be stored in the component. Echo or print are not captured, so do not use them.

Processor tasks

When your task runs a processor, you can access data via $this->getProperty() in the class-based processor. The same applies to the run and task objects:

<?php
$task = $this->getProperty('task');
$run = $this->getProperty('run');