silverstripe-framework/Forms/DefaultFormFactory.php

<?php

namespace SilverStripe\Forms;

use InvalidArgumentException;
use SilverStripe\Control\Controller;
use SilverStripe\Core\Extensible;

/**
 * Default form builder class.
 *
 * @internal WARNING: Experimental and volatile API.
 *
 * Allows extension by either controller or object via the following methods:
 * - updateFormActions
 * - updateFormValidator
 * - updateFormFields
 * - updateForm
 */
class DefaultFormFactory implements FormFactory {
	use Extensible;

	public function __construct() {
		$this->constructExtensions();
	}

	public function getForm(Controller $controller, $name = FormFactory::DEFAULT_NAME, $context = [])
	{
		// Validate context
		foreach($this->getRequiredContext() as $required) {
			if (!isset($context[$required])) {
				throw new InvalidArgumentException("Missing required context $required");
			}
		}

		$fields = $this->getFormFields($controller, $name, $context);
		$actions = $this->getFormActions($controller, $name, $context);
		$validator = $this->getFormValidator($controller, $name, $context);
		$form = Form::create($controller, $name, $fields, $actions, $validator);

		// Extend form
		$this->invokeWithExtensions('updateForm', $form, $controller, $name, $context);

		// Populate form from record
		$form->loadDataFrom($context['Record']);

		return $form;
	}

	/**
	 * Build field list for this form
	 *
	 * @param Controller $controller
	 * @param string $name
	 * @param array $context
	 * @return FieldList
	 */
	protected function getFormFields(Controller $controller, $name, $context = []) {
		// Fall back to standard "getCMSFields" which itself uses the FormScaffolder as a fallback
		// @todo Deprecate or formalise support for getCMSFields()
		$fields = $context['Record']->getCMSFields();
		$this->invokeWithExtensions('updateFormFields', $fields, $controller, $name, $context);
		return $fields;
	}

	/**
	 * Build list of actions for this form
	 *
	 * @param Controller $controller
	 * @param string $name
	 * @param array $context
	 * @return FieldList
	 */
	protected function getFormActions(Controller $controller, $name, $context = []) {
		// @todo Deprecate or formalise support for getCMSActions()
		$actions = $context['Record']->getCMSActions();
		$this->invokeWithExtensions('updateFormActions', $actions, $controller, $name, $context);
		return $actions;
	}

	/**
	 * @param Controller $controller
	 * @param string $name
	 * @param array $context
	 * @return null|Validator
	 */
	protected function getFormValidator(Controller $controller, $name, $context = []) {
		$validator = null;
		if ($context['Record']->hasMethod('getCMSValidator')) {
			// @todo Deprecate or formalise support for getCMSValidator()
			$validator = $context['Record']->getCMSValidator();
		}

		// Extend validator
		$this->invokeWithExtensions('updateFormValidator', $validator, $controller, $name, $context);
		return $validator;
	}

	/**
	 * Return list of mandatory context keys
	 *
	 * @return mixed
	 */
	public function getRequiredContext()
	{
		return ['Record'];
	}
}