ProcessWire Migrations

SystemMigrations.php

<?php

/**
 * ProcessWire System Migrations
 *
 * @author Rasmus Schultz
 * @website http://blog.mindplay.dk/
 * @license GPL v3
 */

/**
 * System Migrations Module
 */
class SystemMigrations extends WireData implements Module, ConfigurableModule
{
    /**
     * @return array module information
     */
    public static function getModuleInfo()
    {
        return array(
            'title'      => 'Migrations',
            'version'    => 100,
            'summary'    => 'Records and integrates changes to Templates and Fields.',
            'permission' => 'template-admin',
            'href'       => 'https://github.com/mindplay-dk/SystemMigrations',
            'singular'   => true,
            'autoload'   => true,
            'requires'   => array('ProcessField', 'ProcessTemplate'),
        );
    }

    /**
     * Initialize module settings.
     */
    public function __construct()
    {
        $this->addHookAfter('Fields::load', $this, 'hookFieldLoaded');
        $this->addHookAfter('ProcessField::fieldSaved', $this, 'hookFieldSaved');

        $this->data_path = dirname(__FILE__) . DIRECTORY_SEPARATOR . 'data';
    }

    /**
     * @var string path to data root-folder (where migration files are stored)
     */
    protected $data_path;

    /**
     * @var string file-name of the last migration read and applied
     */
    public $last_read;

    /**
     * @var string file-name of the last migration written
     */
    public $last_write;

    /**
     * Apply default configuration.
     */
    public function ___install()
    {
        // ...
    }

    /**
     * @var string file-name to which the recorded set of migrations will be written
     */
    protected $filename;

    /**
     * @var array list of recorded function-calls, nested arrays like:
     *            array('method' => $method, 'params' => $params)
     */
    protected $recorded = array();

    /**
     * Method to initialize the module.
     *
     * While the method is required, if you don't need it, then just leave the implementation blank.
     *
     * This is called after ProcessWire's API is fully ready for use and hooks. It is called at the end of the
     * bootstrap process. This is before PW has started retrieving or rendering a page. If you need to have the
     * API ready with the $page ready as well, then see the ready() method below this one.
     */
    public function init()
    {
        $this->filename = date('Y-m-d-H-i-s') . '.json';
    }

    /**
     *
      */
    public function ready()
    {
        if ($this->page->template != 'admin') {
            return;
        }
    }

    /**
     * Record a function-call as part of a migration
     *
     * @param string $method method-name
     * @param array $params method arguments
     */
    protected function record($method, array $params)
    {
        $this->recorded[] = array('method' => $method, 'params' => $params);
    }

    /**
     * Return an InputfieldsWrapper of Inputfields used to configure the class
     *
     * @param array $data Array of config values indexed by field name
     *
     * @return InputfieldsWrapper
     */
    public static function getModuleConfigInputfields(array $data)
    {
        // ...
    }

    /**
     * @var array list of Field properties and settings at the time of loading
     */
    protected $old_data = array();

    /**
     * @param HookEvent $event
     *
     * @see WireSaveableItems::___load()
     * @see Fields::___load()
     */
    public function hookFieldLoaded(HookEvent $event)
    {
        /**
         * @var WireArray $fields
         */

        #$event->object

        $fields = $event->argumentsByName('items');

        foreach ($fields as $field) {
            $this->old_data[$field->id] = $this->getFieldData($field);
        }
    }

    /**
     * @param HookEvent $event
     *
     * @see ProcessField::___fieldSaved()
     */
    public function hookFieldSaved(HookEvent $event)
    {
        /**
         * @var Field $field
         */

        $field = $event->argumentsByName('field');

        header('Content-type: text/plain');

        $data = $this->getFieldData($field);

        $diff = array();

        foreach ($this->old_data[$field->id] as $name => $value) {
            if ($value !== $data[$name]) {
                $diff[$name] = $data[$name];
            }
        }

        if (count($diff)) {
            $this->record('updateField', array(
                    'name' => $this->old_data[$field->id]['name'],
                    'data' => $diff)
            );
        }
    }

    /**
     * Apply updates to a Field
     *
     * The name is the preferred way to find an existing Field, since the ID could
     * differ on another system. The name is the current name, before applying the
     * update - if the field's name has changed, the new name is in $data['name']
     *
     * @param string $name the (current) name of the Field
     * @param array $data new properties and settings for the Field
     */
    protected function updateField($name, array $data)
    {
        // ...
    }

    /**
     * Extract all important Field properties and settings
     *
     * @param Field $field
     * @return array
     */
    protected function getFieldData(Field $field)
    {
        static $FIELD_SETTINGS = array(
            'id',
            'name',
            'flags',
            'label',
            # 'type'
            # 'prevTable',
            # 'prevFieldtype'
        );

        $data = array();

        foreach ($field as $name => $value) {
            $data[$name] = $value;
        }

        foreach ($FIELD_SETTINGS as $name) {
            $data[$name] = $field->{$name};
        }

        return $data;
    }

    /**
     * Write recorded changes to a migration file.
     */
    public function __destruct()
    {
        if (count($this->recorded)) {
            file_put_contents(
                /* $filename: */ $this->data_path . DIRECTORY_SEPARATOR . $this->filename,
                /* $data: */ json_encode($this->recorded)
            );
        }
    }
}