How does Magento 2 prepare a backend config form field for rendering?

dmitrii_fediuk · November 14, 2015, 2:21pm

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Block/System/Config/Form.php#L458


public function getConfigValue($path)
{
    return $this->_scopeConfig->getValue($path, $this->getScope(), $this->getScopeCode());
}


/**
 * @return \Magento\Backend\Block\Widget\Form|\Magento\Framework\View\Element\AbstractBlock
 */
protected function _beforeToHtml()
{
    $this->initForm();
    return parent::_beforeToHtml();
}


/**
 * Append dependence block at then end of form block
 *
 * @param string $html
 * @return string
 */
protected function _afterToHtml($html)

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Block/System/Config/Form.php#L170


public function initForm()
{
    $this->_initObjects();


    /** @var \Magento\Framework\Data\Form $form */
    $form = $this->_formFactory->create();
    /** @var $section \Magento\Config\Model\Config\Structure\Element\Section */
    $section = $this->_configStructure->getElement($this->getSectionCode());
    if ($section && $section->isVisible($this->getWebsiteCode(), $this->getStoreCode())) {
        foreach ($section->getChildren() as $group) {
            $this->_initGroup($group, $section, $form);
        }
    }


    $this->setForm($form);
    return $this;
}


/**
 * Initialize config field group
 *

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Block/System/Config/Form.php#L224


    $elementId = $this->_generateElementId($group->getPath());


    $this->_populateDependenciesBlock($dependencies, $elementId, $elementName);


    if ($group->shouldCloneFields()) {
        $cloneModel = $group->getCloneModel();
        foreach ($cloneModel->getPrefixes() as $prefix) {
            $this->initFields($fieldset, $group, $section, $prefix['field'], $prefix['label']);
        }
    } else {
        $this->initFields($fieldset, $group, $section);
    }


    $this->_fieldsets[$group->getId()] = $fieldset;
}


/**
 * Return dependency block object
 *
 * @return \Magento\Backend\Block\Widget\Form\Element\Dependence
 */

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Block/System/Config/Form.php#L284


                $groupPath = $element->getGroupPath();
                if (!isset($extraConfigGroups[$groupPath])) {
                    $this->_configData = $this->_configDataObject->extendConfig(
                        $groupPath,
                        false,
                        $this->_configData
                    );
                    $extraConfigGroups[$groupPath] = true;
                }
            }
            $this->_initElement($element, $fieldset, $path, $fieldPrefix, $labelPrefix);
        }
    }
    return $this;
}


/**
 * Initialize form element
 *
 * @param \Magento\Config\Model\Config\Structure\Element\Field $field
 * @param \Magento\Framework\Data\Form\Element\Fieldset $fieldset

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Block/System/Config/Form.php#L300-L382


protected function _initElement(
    \Magento\Config\Model\Config\Structure\Element\Field $field,
    \Magento\Framework\Data\Form\Element\Fieldset $fieldset,
    $path,
    $fieldPrefix = '',
    $labelPrefix = ''
) {
    $inherit = true;
    $data = null;
    if (array_key_exists($path, $this->_configData)) {
        $data = $this->_configData[$path];
        $inherit = false;
    } elseif ($field->getConfigPath() !== null) {
        $data = $this->getConfigValue($field->getConfigPath());
    } else {
        $data = $this->getConfigValue($path);
    }
    $fieldRendererClass = $field->getFrontendModel();
    if ($fieldRendererClass) {
        $fieldRenderer = $this->_layout->getBlockSingleton($fieldRendererClass);
    } else {
        $fieldRenderer = $this->_fieldRenderer;
    }


    $fieldRenderer->setForm($this);
    $fieldRenderer->setConfigData($this->_configData);


    $elementName = $this->_generateElementName($field->getPath(), $fieldPrefix);
    $elementId = $this->_generateElementId($field->getPath($fieldPrefix));


    if ($field->hasBackendModel()) {
        $backendModel = $field->getBackendModel();
        $backendModel->setPath(
            $path
        )->setValue(
            $data
        )->setWebsite(
            $this->getWebsiteCode()
        )->setStore(
            $this->getStoreCode()
        )->afterLoad();
        $data = $backendModel->getValue();
    }


    $dependencies = $field->getDependencies($fieldPrefix, $this->getStoreCode());
    $this->_populateDependenciesBlock($dependencies, $elementId, $elementName);


    $sharedClass = $this->_getSharedCssClass($field);
    $requiresClass = $this->_getRequiresCssClass($field, $fieldPrefix);


    $formField = $fieldset->addField(
        $elementId,
        $field->getType(),
        [
            'name' => $elementName,
            'label' => $field->getLabel($labelPrefix),
            'comment' => $field->getComment($data),
            'tooltip' => $field->getTooltip(),
            'hint' => $field->getHint(),
            'value' => $data,
            'inherit' => $inherit,
            'class' => $field->getFrontendClass() . $sharedClass . $requiresClass,
            'field_config' => $field->getData(),
            'scope' => $this->getScope(),
            'scope_id' => $this->getScopeId(),
            'scope_label' => $this->getScopeLabel($field),
            'can_use_default_value' => $this->canUseDefaultValue($field->showInDefault()),
            'can_use_website_value' => $this->canUseWebsiteValue($field->showInWebsite())
        ]
    );
    $field->populateInput($formField);


    if ($field->hasValidation()) {
        $formField->addClass($field->getValidation());
    }
    if ($field->getType() == 'multiselect') {
        $formField->setCanBeEmpty($field->canBeEmpty());
    }
    if ($field->hasOptions()) {
        $formField->setValues($field->getOptions());
    }
    $formField->setRenderer($fieldRenderer);
}

dmitrii_fediuk · November 14, 2015, 4:51pm