rss-bridge/formats/JsonFormat.php

<?php
/**
* Json
* Builds a JSON string from $this->items and return it to browser.
*/
class JsonFormat extends FormatAbstract {

	public function stringify(){
		$items = $this->getItems();
		return json_encode($items, JSON_PRETTY_PRINT);
	}

	public function display(){
		$this
			->setContentType('application/json')
			->callContentType();

		return parent::display();
	}
}