使用PHP将JSON数据追加到服务器上的JSON文件中

我在服务器上存储了一个JSON文件，需要向其中添加数据。我已成功将文件检索到内存中并成功解析了文件。我很难将新的JSON数据放置在正确的位置。

这是我的JSON文件的格式：

{
  "emails": [

              {
                "group": "1st Group",
                "list": [
                          {
                            "id": 1,
                            "subject": "Testing 1"
                          },
                          {
                            "id": 2,
                            "subject": "Testing 2"
                          }
                        ] // End list array
              }, // End 1st Group 

              {
                "group": "2nd Group",
                "list": [
                          {
                            "id": 3,
                            "subject": "Testing 3"
                          },
                          {
                            "id": 4,
                            "subject": "Testing 4"
                          }
                        ] // End list array
              } // End 2nd Group

              /* NEED TO INSERT NEW DATA HERE */

             ] // End emails array
}

我试图group list在最后一个之后追加一个新的group list。在此示例中，该代码将在此行之后：} // End 2nd Group。

这是我的PHP代码，该代码从我的服务器获取JSON文件并进行解析：

$getJSON = file_get_contents('emails.json');
$tempArray = json_decode($getJSON, true);

$numberOfGroups = count($tempArray['emails'][0]);

这是我的php代码，用于创建JSON文件的格式/布局：

$groupArray = array();

$json = array( 'emails' => array() );

foreach ($contextIORequest->getData() as $message) {

  $newTZ = new DateTimeZone("America/Chicago");
  $currentTime = new DateTime();
  $currentTime = DateTime::createFromFormat('U', $message['date_received']);
  $currentTime->setTimezone($newTZ);
  $formattedDateReceived = $currentTime->format('F j, Y');

  if (!in_array($formattedDateReceived, $groupArray)) {
      array_push( $json['emails'],
          array(
               'group' => $formattedDateReceived,
               'list' => array()
          )
      );
      $groupArray[] = $formattedDateReceived;
  }

  $body = str_replace(array("\r\n","\n"),"", $message['body'][0]['content']);
  $newBody = preg_replace('!\s+!', ' ', $body);

  array_push($json['emails'][array_search($formattedDateReceived,$groupArray)]['list'],
      array(
        'id' => $message['message_id'],
        'subject'=> addslashes($message['subject']),
        'to' => array("Me"),
        'body' => $newBody,
        'time' => $formattedDateReceived,
        'datetime' => $formattedDateReceived,
        'from' => $message['addresses']['from']['name'],
        'dp' => "assets/img/profiles/avatar.jpg",
        'dpRetina' => "assets/img/profiles/avatar2x.jpg"
      )
  );

} // end foreach loop

// Output the JSON
header('Content-Type: application/json');
echo json_encode($json);

那么我将如何group list在最后一个之后追加一个新的group list呢？这需要在没有实际包含emails用于创建JSON的数组的情况下完成。