pixelfed/app/Util/ActivityPub/DiscoverActor.php

<?php

namespace App\Util\ActivityPub;

use \Zttp\Zttp;

class DiscoverActor {

  protected $url;
  protected $response;

  public function __construct($url)
  {
    $this->url = $url;
  }

  public function fetch()
  {
    $res = Zttp::withHeaders([
      'Accept' => 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"',
      'User-Agent' => 'PixelFedBot - https://pixelfed.org'
    ])->get($this->url);
    $this->response = $res->body();
    return $this;
  }

  public function getResponse()
  {
    return json_decode($this->response, true);
  }

  public function getJsonResponse()
  {
    return $this->response;
  }

  public function discover()
  {
    $this->fetch();
    $res = $this->getResponse();

    if(empty($res) || !in_array('type', $res) || $res['type'] !== 'Person') {
      throw new \Exception('Invalid Actor Object');
    }

    return $res;
  }

}