Build Gist comments feed for specific user, using GitHub API.

CommentsFeed.php

<?php

namespace Rarst\GitHub\Gist;

use GuzzleHttp\Client;
use GuzzleHttp\Command\Guzzle\Description;
use GuzzleHttp\Command\Guzzle\GuzzleClient;

/**
 * Build Gist comments feed for specific user, using GitHub API.
 *
 * Example use:
 *
 *  $feed = new CommentsFeed('Rarst');
 *  echo $feed->fetch()->render();
 *
 * Passing own instances of Guzzle and Mustache set up for authorization and caching recommended.
 */
class CommentsFeed
{
    const DATE_GITHUB = 'Y-m-d\TH:i:s\Z';
    protected $user;
    protected $since;
    protected $comments = [ ];

    public function __construct($user, $since = '-1 month')
    {
        $this->user  = $user;
        $this->since = $since;
    }

    public function fetch(Client $client = null)
    {
        if (empty( $client )) {
            $client = new Client;
        }

        $description  = new Description($this->getServiceDescription());
        $guzzleClient = new GuzzleClient($client, $description);

        $command = $guzzleClient->getCommand('GetGists', [
            'user'  => $this->user,
            'since' => gmdate(self::DATE_GITHUB, strtotime($this->since)),
        ]);

        $gists = $guzzleClient->execute($command);

        foreach ($gists as $gist) {

            if (0 === $gist['comments']) {
                continue;
            }

            $command  = $guzzleClient->getCommand('GetComments', [ 'id' => $gist['id'] ]);
            $comments = $guzzleClient->execute($command);

            foreach ($comments as $comment) {

                if (0 === strcasecmp($this->user, $comment['user']['login'])) {
                    continue;
                }

                $comment['gist_id']       = $gist['id'];
                $comment['gist_author']   = $gist['user']['login'];
                $filenames                = array_keys($gist['files']);
                $comment['gist_filename'] = array_shift($filenames);
                $comment['updated_at']    = date(DATE_RSS, strtotime($comment['updated_at']));
                $this->comments[]         = $comment;
            }

        }

        return $this;
    }

    public function getServiceDescription()
    {
        return [
            'name'        => 'Gist',
            'apiVersion'  => 'v3',
            'baseUrl'     => 'https://api.github.com/',
            'description' => 'Gists and comments access',
            'operations'  => [
                'GetGists'    => [
                    'responseModel' => 'getResponse',
                    'httpMethod'    => 'GET',
                    'uri'           => '/users/{user}/gists',
                    'parameters'    => [
                        'user'  => [
                            'location' => 'uri',
                            'required' => true,
                        ],
                        'since' => [
                            'location' => 'query',
                        ],
                    ],
                ],
                'GetComments' => [
                    'responseModel' => 'getResponse',
                    'httpMethod'    => 'GET',
                    'uri'           => '/gists/{id}/comments',
                    'parameters'    => [
                        'id' => [
                            'location' => 'uri',
                            'required' => true,
                        ],
                    ],
                ],
            ],
            'models'      => [
                'getResponse' => [
                    'type'                 => 'object',
                    'additionalProperties' => [
                        'location' => 'json'
                    ]
                ]
            ]
        ];
    }

    public function render(\Mustache_Engine $mustache = null)
    {
        if (empty( $mustache )) {
            $mustache = new \Mustache_Engine();
        }

        return $mustache->render(
            $this->getRssTemplate(),
            [
                'user'     => $this->user,
                'comments' => $this->comments,
            ]
        );
    }

    public function getRssTemplate()
    {
        $template = <<<RSS
<?xml version = '1.0' ?>
<rss version="2.0">
    <channel>
        <title>Gist comments for {{user}}</title>
        {{#comments}}
        <item>
            <title>Comment by {{user.login}} on {{gist_filename}}</title>
            <description>{{body}}</description>
            <link>https://gist.github.com/{{gist_author}}/{{gist_id}}/#comment-{{id}}</link>
            <guid isPermaLink="true">https://gist.github.com/{{gist_author}}/{{gist_id}}/#comment-{{id}}</guid>
            <pubDate>{{updated_at}}</pubDate>
        </item>
        {{/comments}}
    </channel>
</rss>
RSS;

        return $template;
    }
}