pixelfed/app/Http/Controllers/Api/ApiController.php

<?php

namespace App\Http\Controllers\Api;

use Illuminate\Http\Request;
use App\Http\Controllers\Controller;

class ApiController extends Controller {
  public function json($res, $headers = [], $code = 200) {
    return response()->json($res, $code, $this->filterHeaders($headers), JSON_UNESCAPED_SLASHES);
  }

  public function linksForCollection($paginator) {
    $link = null;

    if ($paginator->onFirstPage()) {
      if ($paginator->hasMorePages()) {
          $link = '<'.$paginator->nextPageUrl().'>; rel="prev"';
      }
    } else {
      if ($paginator->previousPageUrl()) {
          $link = '<'.$paginator->previousPageUrl().'>; rel="next"';
      }

      if ($paginator->hasMorePages()) {
          $link .= ($link ? ', ' : '').'<'.$paginator->nextPageUrl().'>; rel="prev"';
      }
    }

    return $link;
  }

  private function filterHeaders($headers) {
    return array_filter($headers, function($v, $k) {
      return $v != null;
    }, ARRAY_FILTER_USE_BOTH);
  }
}