PHP在发送ajax请求时不返回任何数据

当我向getMessages.php文件发送ajax post请求时，它不会返回任何内容

我尝试过手动设置数组值并在控制台中打印它们，这似乎很有效

getMessages.php

<?php

require_once "mysqli.php";

$data = array();

if (isset($_POST['getChat']) && !empty($_POST['getChat'])) {
    $username = $_SESSION["username"];

    $result = mysqli_query($conn, "SELECT msg_startuser, msg, time 
        FROM messages 
        WHERE msg_startuser = '{$username}' and msg_enduser = 'mariokiller470' 
        UNION 
        SELECT msg_startuser, msg, time 
        From messages 
        WHERE msg_startuser = 'mariokiller470' and msg_enduser = '{$username}' 
        order by time;
    ");

    while ($row = mysqli_fetch_array($result)) {
        $data['startuser'] = $row['msg_startuser'];
        $data['msg'] = $row['msg'];
    }
}

echo json_encode($data);
exit;
?>

---

我希望它在控制台中打印出来进行测试。

循环中的数据会一次又一次地被覆盖，我想您应该这样做：

$x = 0;
while ($row = mysqli_fetch_array ($result)) {
        $data[$x]['startuser'] = $row['msg_startuser'];
        $data[$x]['msg'] = $ row['msg'];
        $x++;
}

哎呀

我忘了开始上课了

---

谢谢帕特里克

这将解决问题，因为您将响应作为对象返回

An更新：

You will need to initialize session

数组的数据参数应该在if语句中

请尝试下面的代码

<?php

require_once "mysqli.php";
session_start();

if (isset($_POST['getChat']) && !empty($_POST['getChat'])) {
    $username = $_SESSION["username"];

$data = array();


    $result = mysqli_query($conn, "SELECT msg_startuser, msg, time 
        FROM messages 
        WHERE msg_startuser = '{$username}' and msg_enduser = 'mariokiller470' 
        UNION 
        SELECT msg_startuser, msg, time 
        From messages 
        WHERE msg_startuser = 'mariokiller470' and msg_enduser = '{$username}' 
        order by time;
    ");

    while ($row = mysqli_fetch_array($result)) {
         $startuser = $row['msg_startuser'];
        $msg = $row['msg'];

$data = array("startuser" =>$startuser, "msg" =>$msg);
    }


echo json_encode($data);
exit;

}
?>

---

您好，您可以这样尝试：

php脚本：

<?php
require_once "mysqli.php";
session_start();// start the session
$data = array();
if (isset($_SESSION["username"])) {
  if (isset($_POST["endUser"]) &&  isset($_POST["action"])) {
  $case = $_POST["action"];
  $endUser = $_POST["endUser"];
  $username = $_SESSION["username"];
  switch (case) {
    case 'getChat':
    $result = mysqli_query($conn, "SELECT msg_startuser, msg, time
        FROM messages
        WHERE msg_startuser = '{$username}' and msg_enduser = '{$endUser}'
        UNION
        SELECT msg_startuser, msg, time
        From messages
        WHERE msg_startuser = '{$endUser}' and msg_enduser = '{$username}'
        order by time;
    ");

    while ($row = mysqli_fetch_assoc($resultado)) {
        if (isset($row['msg_startuser']) && isset($row['msg'])) {
          $temp = array(
            "user"=>$row['msg_startuser'],
            "msg"=>$row['msg']
          );
        }
        $data[] = $temp;
    }
    echo json_encode($data);
      break;
  }
  }
}else {
  echo "error-403";
}
 ?>

---

希望它有帮助

可能是问题的根源，也可能不是问题的根源，但您似乎没有开始会话。警告：您对参数化预处理语句非常开放，应该使用参数化预处理语句，而不是手动生成查询。它们由或提供。永远不要相信任何类型的输入，尤其是来自客户端的输入。即使您的查询仅由受信任的用户执行，。注意：许多问题都可以通过检测和解决，因此所犯的任何错误都不会轻易被忽略。许多返回值不能忽略，您必须注意每一个。异常不需要单独检查，它们可以在更高级别的代码中被捕获。你是在@Bean还是这只是一个点击并运行的过程？我在这里。我忘了启动会话。只需使用

$data[]=['startuser'=>$row['msg\u startuser']，'msg'=>$row['msg']

。

$x

是毫无意义的，很容易以一种糟糕的方式弄糟。也不清楚

$data

是如何以一个神秘而混乱的空格结束的

$data

。这无法解释“它不会返回任何东西”，它只会解释结果较少的情况（一个）比预期的要多。我认为这不是答案，因为OP看起来根本不想要循环，因为他们似乎正在获取一条唯一的记录。@Dharman查询中没有

限制，因此可以返回任意数量的记录。@tadman True，可能是任何一种方式，但答案看起来更像是一条注释而不是t他给出了一个问题的解决方案。嗯。我尝试了你的代码，但从console.log中什么也没有得到
console.log(data.startuser, data.msg);

<?php
require_once "mysqli.php";
session_start();// start the session
$data = array();
if (isset($_SESSION["username"])) {
  if (isset($_POST["endUser"]) &&  isset($_POST["action"])) {
  $case = $_POST["action"];
  $endUser = $_POST["endUser"];
  $username = $_SESSION["username"];
  switch (case) {
    case 'getChat':
    $result = mysqli_query($conn, "SELECT msg_startuser, msg, time
        FROM messages
        WHERE msg_startuser = '{$username}' and msg_enduser = '{$endUser}'
        UNION
        SELECT msg_startuser, msg, time
        From messages
        WHERE msg_startuser = '{$endUser}' and msg_enduser = '{$username}'
        order by time;
    ");

    while ($row = mysqli_fetch_assoc($resultado)) {
        if (isset($row['msg_startuser']) && isset($row['msg'])) {
          $temp = array(
            "user"=>$row['msg_startuser'],
            "msg"=>$row['msg']
          );
        }
        $data[] = $temp;
    }
    echo json_encode($data);
      break;
  }
  }
}else {
  echo "error-403";
}
 ?>

 function getChat() {

    return $.ajax({
         url: 'getMessages.php',
         type: 'POST',
         data: {action: 'getChat',endUser:'mariokiller470'},
         dataType: 'JSON'
     })

 }

getChat()
.done(function(response){
  console.log(response);
})