ListJson.php

<?php
namespace Vendor\Extension\View\Record;

class ListJson extends \TYPO3\CMS\Extbase\Mvc\View\JsonView {

	private static $uriBuilder = null;

	public function typolink($page, $uid = null) {
		if ($page) {
			if (self::$uriBuilder === null) {
				self::$uriBuilder = $this->controllerContext->getUriBuilder();
			}
			self::$uriBuilder->reset();
			if ($uid) {
				self::$uriBuilder->setArguments(array('tx_extension_list[uid]' => (int)$uid));
				self::$uriBuilder->setUseCacheHash(true);
			}
			self::$uriBuilder->setTargetPageUid($page);
			return self::$uriBuilder->build();
		}
		return '';
	}

	/**
	 * Renders the view
	 * @return string The rendered view as JSON
	 */
	public function render() {

		// This should be set by \TYPO3\CMS\Extbase\Mvc\View\JsonView,
		// but for some reason that's not working. Maybe related to this
		// issue: https://forge.typo3.org/issues/60624
		//
		// The following option has to be set, in order to get this working:
		// 'page.config.disableCharsetHeader = 1'
		header('Content-Type: application/json; charset=utf-8');

		$records = array();
		foreach ($this->variables['records'] as $record) {
			$records[] = $record->toArray($this);
		}
		return json_encode($records);
	}
}