#concrete5 SmartFormat RSS (An example to customize Zend Feed with Extension)

app.php

<?php
// application/bootstrap/app.php

$app->make('Concrete\Core\Routing\RouterInterface')->register('/feed/smartnews', function() use ($app) {
    /**
     * Registering Extension for Zend Feed
     */
    /** @var \Zend\ServiceManager\AbstractPluginManager $manager */
    $manager = \Zend\Feed\Writer\Writer::getExtensionManager();
    $manager->setInvokableClass(
        'SmartNewsRendererFeed',
        'Application\Src\Feed\Writer\Extension\SmartNews\Renderer\Feed'
    );
    $manager->setInvokableClass(
        'SmartNewsEntry',
        'Application\Src\Feed\Writer\Extension\SmartNews\Entry'
    );
    $manager->setInvokableClass(
        'SmartNewsRendererEntry',
        'Application\Src\Feed\Writer\Extension\SmartNews\Renderer\Entry'
    );
    \Zend\Feed\Writer\Writer::registerExtension('SmartNews');
    
    /**
     * Get pages
     */
    $pl = new \Concrete\Core\Page\PageList();
    $pl->sortByPublicDateDescending();
    
    $vp = \Concrete\Core\Permission\Key\Key::getByHandle('view_page');
    $guest = \Concrete\Core\User\Group\Group::getByID(GUEST_GROUP_ID);
    $access = \Concrete\Core\Permission\Access\Entity\GroupEntity::getOrCreate($guest);
    // we set page permissions to be Guest group only, because
    // authentication won't work with RSS feeds
    $pl->setPermissionsChecker(function($page) use ($vp, $access) {
        $vp->setPermissionObject($page);
        $pa = $vp->getPermissionAccessObject($page);
        if (!is_object($pa)) {
            return false;
        }
        return $pa->validateAccessEntities(array($access));
    });
    
    // Filter By Page Type
    $pl->filterByPageTypeHandle('article');
    
    $pagination = $pl->getPagination();
    
    if ($pagination->getTotalResults() > 0) {
        $request = \Concrete\Core\Http\Request::getInstance();
    
        /**
         * Retrieve site information
         */
        $site = $app->make('site')->getSite();
        $home = $site->getSiteHomePageObject('ACTIVE');
        $description = ($site->getAttribute('description')) ? $site->getAttribute('description') : t('No Description');
        $thumbnail = $site->getAttribute('thumbnail');
        
        /**
         * Setup Feed Object
         */
        $writer = new \Zend\Feed\Writer\Feed();
        $writer->setTitle($site->getSiteName());
        $writer->setLink($site->getSiteCanonicalURL());
        $writer->setDescription($description);
        if (is_object($thumbnail) {
            $writer->setImage(array(
                'uri' => $thumbnail->getURL(),
                'title' => $site->getSiteName(),
                'link' => $site->getSiteCanonicalURL()
            ));
        }
        $writer->setDateCreated(new DateTime());
    
        /** @var \Concrete\Core\Page\Page|\Concrete\Core\Page\Collection\Collection|\Page $p */
        foreach($pagination->getCurrentPageResults() as $p) {
            $entry = $writer->createEntry();
            $entry->setTitle($p->getCollectionName());
            if ($description = $p->getCollectionDescription()) {
                $entry->setDescription($description);
            }
            $entry->setDateCreated(strtotime($p->getCollectionDatePublic()));
            $entry->setLink($p->getCollectionLink(true));
    
            $uid = $p->getCollectionUserID();
            /** @var \Concrete\Core\User\UserInfo $ui */
            $ui = $app->make('Concrete\Core\User\UserInfoFactory')->getByID($uid);
            if ($ui !== null) {
                $entry->addAuthor(array(
                    'name' => $ui->getUserDisplayName(),
                    'uri' => (string) $ui->getUserPublicProfileUrl()
                ));
            }
    
            $thumbnail = $p->getAttribute('thumbnail');
            if (is_object($thumbnail)) {
                $entry->setSmartNewsThumbnail((string) $thumbnail->getURL());
            }
    
            if ($tracking_id = $site->getAttribute('tracking_id'))
                $entry->setSmartNewsAnalytics(array(
                    'trackingid' => $tracking_id,
                    'uri' => $p->getCollectionLink(true)
                ));
            }
    
            $a = \Concrete\Core\Area\Area::get($p, 'Main');
            $blocks = $a->getAreaBlocksArray();
            $request->setCurrentPage($p);
            ob_start();
            foreach($blocks as $b) {
                $bv = new \Concrete\Core\Block\View\BlockView($b);
                $bv->render('view');
            }
            $content = ob_get_contents();
            ob_end_clean();
    
            if (!$content) {
                $content = t('No Content.');
            }
            $entry->setContent($content);
    
            $writer->addEntry($entry);
        }
    
        return \Concrete\Core\Http\Response::create(
            $writer->export('rss'),
            200,
            array('Content-Type' => 'text/xml')
        );
    }
}

Entry.php

<?php
// application/src/Feed/Writer/Extension/SmartNews/Entry.php

namespace Application\Src\Feed\Writer\Extension\SmartNews;

use Zend\Feed\Exception\InvalidArgumentException;
use Zend\Feed\Uri;
use Zend\Feed\Writer\Exception\BadMethodCallException;
use Zend\Stdlib\StringUtils;
use Zend\Stdlib\StringWrapper\StringWrapperInterface;

class Entry
{
    /**
     * Array of Feed data for rendering by Extension's renderers
     *
     * @var array
     */
    protected $data = array();

    /**
     * Encoding of all text values
     *
     * @var string
     */
    protected $encoding = 'UTF-8';

    /**
     * The used string wrapper supporting encoding
     *
     * @var StringWrapperInterface
     */
    protected $stringWrapper;

    public function __construct()
    {
        $this->stringWrapper = StringUtils::getWrapper($this->encoding);
    }

    /**
     * Set feed encoding
     *
     * @param  string $enc
     * @return Entry
     */
    public function setEncoding($enc)
    {
        $this->stringWrapper = StringUtils::getWrapper($enc);
        $this->encoding      = $enc;
        return $this;
    }

    /**
     * Get feed encoding
     *
     * @return string
     */
    public function getEncoding()
    {
        return $this->encoding;
    }

    /**
     * Set a thumbnail of this entry
     *
     * @param string $url
     * @throws InvalidArgumentException
     * @return $this
     */
    public function setSmartNewsThumbnail($url)
    {
        if (empty($url) || !is_string($url) || !Uri::factory($url)->isValid()) {
            throw new InvalidArgumentException('Invalid parameter: parameter must be a non-empty string and valid URI/IRI');
        }
        $this->data['thumbnail'] = $url;

        return $this;
    }

    /**
     * Set the analytics code
     *
     * @param array $data
     * @throws InvalidArgumentException
     * @return $this
     */
    public function setSmartNewsAnalytics(array $data)
    {
        if (!array_key_exists('trackingid', $data)
            || empty($data['trackingid'])
            || !is_string($data['trackingid'])
        ) {
            throw new InvalidArgumentException('Invalid parameter: Tracking ID must be a non-empty string');
        }

        if (!array_key_exists('uri', $data)
            || empty($data['uri'])
            || !is_string($data['uri'])
            || !Uri::factory($data['uri'])->isValid()
        ) {
            throw new InvalidArgumentException('Invalid parameter: path must be a non-empty string and valid URI');
        }

        $this->data['analytics'] = $data;

        return $this;
    }

    /**
     * Overloading to SmartNews specific setters
     *
     * @param  string $method
     * @param  array $params
     * @throws BadMethodCallException
     * @return mixed
     */
    public function __call($method, array $params)
    {
        $point = lcfirst(substr($method, 12));
        if (!method_exists($this, 'setSmartNews' . ucfirst($point))
            && !method_exists($this, 'addSmartNews' . ucfirst($point))
        ) {
            throw new BadMethodCallException(
                'invalid method: ' . $method
            );
        }
        if (!array_key_exists($point, $this->data)
            || empty($this->data[$point])
        ) {
            return null;
        }
        return $this->data[$point];
    }
}

RendererEntry.php

<?php
// application/src/Feed/Writer/Extension/SmartNews/Renderer/Entry.php

namespace Application\Src\Feed\Writer\Extension\SmartNews\Renderer;

use Zend\Feed\Uri;
use Zend\Feed\Writer\Extension\AbstractRenderer;

class Entry extends AbstractRenderer
{

    /**
     * Set to TRUE if a rendering method actually renders something. This
     * is used to prevent premature appending of a XML namespace declaration
     * until an element which requires it is actually appended.
     *
     * @var bool
     */
    protected $called = false;

    /**
     * @inheritDoc
     */
    public function render()
    {
        $this->_setThumbnail($this->dom, $this->base);
        $this->_setAnalytics($this->dom, $this->base);
        if ($this->called) {
            $this->_appendNamespaces();
        }
    }

    protected function _setThumbnail(\DOMDocument $dom, \DOMElement $root)
    {
        $url = $this->getDataContainer()->getSmartNewsThumbnail();
        if (!$url) {
            return;
        }

        $thumbnail = $dom->createElement('media:thumbnail');
        $thumbnail->setAttribute('url', $url);
        $root->appendChild($thumbnail);
        $this->called = true;
    }

    protected function _setAnalytics(\DOMDocument $dom, \DOMElement $root)
    {
        $data = $this->getDataContainer()->getSmartNewsAnalytics();
        if (!is_array($data)) {
            return;
        }

        $uri = Uri::factory($data['uri']);
        $code = sprintf("<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');

ga('create', '%s', '%s');
ga('require', 'displayfeatures');
ga('set', 'referrer', 'http://www.smartnews.com/');
ga('send', 'pageview', '%s');
  </script>", $data['trackingid'], $uri->getHost(), $uri->getPath());
        $analytics = $dom->createElement('snf:analytics');
        $root->appendChild($analytics);
        $cdata = $dom->createCDATASection($code);
        $analytics->appendChild($cdata);
        $this->called = true;
    }

    /**
     * @inheritDoc
     */
    protected function _appendNamespaces()
    {
        $this->getRootElement()->setAttribute('xmlns:media',
            'http://search.yahoo.com/mrss/');
        $this->getRootElement()->setAttribute('xmlns:snf',
            'http://www.smartnews.be/snf');
    }

}

RendererFeed.php

<?php
// application/src/Feed/Writer/Extension/SmartNews/Renderer/Feed.php

namespace Application\Src\Feed\Writer\Extension\SmartNews\Renderer;

use Zend\Feed\Writer\Extension\AbstractRenderer;

class Feed extends AbstractRenderer
{

    /**
     * Set to TRUE if a rendering method actually renders something. This
     * is used to prevent premature appending of a XML namespace declaration
     * until an element which requires it is actually appended.
     *
     * @var bool
     */
    protected $called = false;

    /**
     * @inheritDoc
     */
    public function render()
    {
        $this->_setFeedLogo($this->dom, $this->base);
        if ($this->called) {
            $this->_appendNamespaces();
        }
    }

    protected function _setFeedLogo(\DOMDocument $dom, \DOMElement $root)
    {
        $image = $this->getDataContainer()->getImage();
        if (!$image) {
            return;
        }
        $logo = $dom->createElement('snf:logo');
        $url = $dom->createElement('url');
        $text = $dom->createTextNode($image['uri']);
        $url->appendChild($text);
        $logo->appendChild($url);
        $root->appendChild($logo);
        $this->called = true;
    }

    /**
     * @inheritDoc
     */
    protected function _appendNamespaces()
    {
        $this->getRootElement()->setAttribute('xmlns:snf',
            'http://www.smartnews.be/snf');
    }
}