PHP-通过循环解析嵌套JSON数组

我正在处理一些JSON数据,如下所示:

    {
  "attachments": [
    {
      "content": "<base 64 encoded attachment>", 
      "content_type": "image/jpeg", 
      "original_name": "image000000.jpg"
    }, 
    {
      "content": "<base 64 encoded attachment>", 
      "content_type": "image/gif", 
      "original_name": "gif0001.jpg"
    }
  ], 
  "source_number": "++614567890"
}

我需要遍历所有附件数组。我可以得到如下单个元素:

$arr = json_decode($jsonobj, true);
echo $arr[attachments][0]["content_type"]; // returns image/jpeg

    foreach($arr[attachments] as $key => $value) {
  $contentType = $arr[attachments][0]["content_type" ;
  $content = $arr[attachments][0]["content" ;
  $originalName = $arr[attachments][0]["original_name" ;
}

这将在循环中为附件数组中的每个项生成一个变量。