如何在服務器發送的事件中使用數據響應

Question

嗨幾天前我問了一個類似的問題，沒有任何迴應。我試圖自己解決這個問題，但沒有成功。 我已經成功地使用了服務器發送的請求，爲數據庫輪詢新條目併成功獲取以json格式返回的數據（在webconsole中確認）。我似乎無法做的是在eSource.onmessage函數中使用其他函數中的數據。

這是jQuery的

<script type="text/javascript"> 

$(document).ready(function() {//READY FUNC 

    //check for browser support 
    if(typeof(EventSource)!=="undefined") { 
     //create an object, passing it the name and location of the server side script 
     var eSource = new EventSource("http://newberylodge.co.uk/webapp/includes/messageRetrieve.php"); 
     //detect message receipt 
     eSource.onmessage = function(event) { 
      //write the received data to the page 
      $.each(data, function(key, val) { 
      //iterate each data 
       var id = val.id; 
       var messageId = val.messageId; 
       var messageSubject = val.messageSubject; 
       var messageContent = val.messageDetail; 

       $('#serverData').append('<div id="' + id + '" class="messageAlert">' + messageSubject + '</div>'); 
       $('#serverData').append('<div id="' + messageId + '" class="messageContent">' + messageContent + '</div>'); 
       $('#' +messageId).append('<input id="' + messageId + '" type="button" class="deleteButton" value="Delete Message" />'); 

      }); 
      //EACH DATA 
     } 

     $(document).on('click', '#' +messageId, function(){ 
     //on click 

      $.post("http://newberylodge.co.uk/webapp/includes/deleteMessage.php",{value1 : messageId}, function() { 
       location.reload(true); 
       alert('Message Deleted'); 
      }); 
      //POST AJAX 
     }); 
     //END ON CLICK 
    }; 
    //TYPE OF EVENT SOURCE   

}); 
//DOCUMENT READY FUNC 
</script> 

這是PHP處理網頁messageReturn.php

<?php 

include_once 'db_connect.php'; 
$return_arr = array(); 
$result = mysqli_query($mysqli, "SELECT * FROM message"); 

while($row = mysqli_fetch_array($result)) {   
    $row_array['id'] = $row['id']; 
    $row_array['messageId'] = $row['messageId']; 
    $row_array['messageSubject'] = $row['messageSubject']; 
    $row_array['messageDetail'] = $row['messageDetail']; 

    array_push($return_arr,$row_array); 

} 

header('Content-Type: text/event-stream'); 
header('Cache-Control: no-cache'); 

echo json_encode($return_arr); 
flush(); 

?> 

這，我相信我會錯了，但不知道如何

 eSource.onmessage = function(event) { 
      //write the received data to the page 
      $.each(data, function(key, val) { 
      //iterate each data 
       var id = val.id; 
       var messageId = val.messageId; 
       var messageSubject = val.messageSubject; 
       var messageContent = val.messageDetail; 

       $('#serverData').append('<div id="' + id + '" class="messageAlert">' + messageSubject + '</div>'); 
       $('#serverData').append('<div id="' + messageId + '" class="messageContent">' + messageContent + '</div>'); 
       $('#' +messageId).append('<input id="' + messageId + '" type="button" class="deleteButton" value="Delete Message" />'); 

      }); 
      //EACH DATA 
     } 

我想要做的是從響應中獲取json數據，以便我可以在腳本中的其他函數中使用它。 任何人都可以協助嗎？

Answer 1

您收到的消息是一個JSON字符串，它在解析成Javascript對象之前無法迭代。

其次，你似乎沒有什麼數據，你使用data，但它從來沒有在任何地方定義，你想要的是event.data

if (typeof (EventSource) !== "undefined") { 

    var eSource = new EventSource("http://newberylodge.co.uk/webapp/includes/messageRetrieve.php"); 

    eSource.onmessage = function (event) { 

     var data = JSON.parse(event.data); 

     $.each(data, function (key, val) { 
      var id = val.id; 
      var messageId = val.messageId; 
      var messageSubject = val.messageSubject; 
      var messageContent = val.messageDetail; 

      $('#serverData').append('<div id="' + id + '" class="messageAlert">' + messageSubject + '</div>'); 
      $('#serverData').append('<div id="' + messageId + '" class="messageContent">' + messageContent + '</div>'); 
      $('#' + messageId).append('<input id="' + messageId + '" type="button" class="deleteButton" value="Delete Message" />'); 

     }); 
    } 

    .... etc