Php 如何将pdf文件编码为base64格式？

我是这样做的。对吗

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除了通过Base-64编码器运行文件并发送结果外？我已将其url保存在数据库中，但根据api要求，我需要以Base-64格式对pdf文件本身进行编码。我需要以编码格式发送pdf文件。您是否尝试在谷歌上搜索base64 encode pdf文件，你会发现成千上万的有用的工具和指南；

    $filename = "../pdfs/reactjs_tutorial.pdf";
    $handle = fopen($filename, 'rb');
    $contents = fread($handle,filesize($filename));
    fclose($handle);
    $encoded = chunk_split(base64_encode($contents));

/*This is how I have done*/

      $query1 = mysqli_query($con, "SELECT  `offer_id` ,  `offer_img_url` ,  `terms` FROM  `offers` LEFT JOIN system ON system.shop_id = offers.shop_id LEFT JOIN bill ON bill.sys_id = system.sys_id WHERE yb_id =  '$yb_id' LIMIT 0 , 30 ");
  if(mysqli_affected_rows($con)>0)
      {
        $data4 = array();
      while ($row = mysqli_fetch_array($query1))
         {
        $data4['offer_id'] = $row['offer_id'];
        $data4['offer_img_url'] = base64_encode($row['offer_img_url']);
        $data4['terms'] = $row['terms'];
         $data2[] = $data4;
      }