调用“json_encode”后 PHP 标头和会话标签不起作用

Question

我正在使用 Ajax 将登录表单详细信息从 HTML 传递到 PHP。详细信息得到正确传递，所有功能都正常工作，警报也根据输出工作。

但是，如果我在json_encode 下面添加以下会话语句，它就不起作用。执行“检查元素”后，Chrome 的“网络选项卡”中的输出是正确的，但标头功能不起作用，也没有出现 Ajax 中指定的成功或失败警报。

代码如下：

<?php
  ob_start();
  session_start();
  $servername = "localhost";
  $username = "root";
  $password = "";
  $dbname = "kites";

  //Create Connection
  $conn = mysqli_connect($servername, $username, $password, $dbname);

  //Check connection
  if(!$conn)
  {
    die("Connection failed: " . mysqli_connect_error());
    alert("Connection failed");
  }
  else
  {
    if( empty($_POST['loginusername']) && empty($_POST['loginpassword']) )
    {
      echo json_encode(array('status'=>false,'msg'=>'No arguments provided'));
    } 
    else
    {

  $loginusername = $_POST['loginusername'];
  $loginpassword = $_POST['loginpassword'];

  $stmt = $conn->prepare("SELECT * FROM register_form WHERE username = ?");
  $stmt->bind_param("s", $loginusername);

  if($stmt->execute())
  {
    $result = $stmt->get_result();
    $num_of_rows = $result->num_rows;
    if($num_of_rows > 0)
    {
      $user = $result->fetch_assoc();
      $salt = $user['salt'];
      $encrypted_password = $user['password'];
      function checkhashSSHA($salt,$password)
      {
        $hash = base64_encode(sha1($password . $salt, true) . $salt);
        return $hash;
      }
      $hash = checkhashSSHA($salt,$loginpassword);
      if($encrypted_password == $hash)
      {
        echo json_encode(array('status'=>true, 'msg'=>'Login Successfull'));
        session_regenerate_id();
        $_SESSION['username']=$loginusername;
        session_write_close();
        //here you can redirect on your file which you want to show after login just change filename ,give it to your filename.
        header("Location:http://localhost/kites/profile.php");
      }
      else
      {
        echo json_encode(array('status'=>false,'msg'=>$encrypted_password ));
      }
    }
    else
    {
      echo json_encode(array('status'=>false,'msg'=>'Wrong username. Please check it and try again'));
    }
  }
  else
  {
    echo json_encode(array('status'=>false,'msg'=>'Something went wrong. Please try again!'));
  }
} } ?> 

如果我删除以下语句：

session_regenerate_id();
$_SESSION['username']=$loginusername;
session_write_close();
header("Location:http://localhost/kites/profile.php");

代码运行正常。

Answer 1

您遇到错误的代码块： 你把它改成

session_regenerate_id();
$_SESSION['username']=$loginusername;
session_write_close();
echo json_encode(array('status'=>true, 'msg'=>'Login Successfull'));

在你的 Ajax 成功函数中你可以做：

if(status){
   //redirect using window.location
   window.location = "your_redirect_url";
}

P

Answer 2

在发送任何输出后，您不能在 PHP 中发送标头。使用输出缓冲 - 解决方法

ob_start(); // you have already start buffering. that's correct
...
echo json_encode(array('status'=>true, 'msg'=>'Login Successfull'));
session_regenerate_id();
$_SESSION['username']=$loginusername;
session_write_close();
//here you can redirect on your file which you want to show after login just change filename ,give it to your filename.
header("Location:http://localhost/kites/profile.php");
ob_end_flush();
...

但毕竟，您不应该在 ajax 调用中使用 header 重定向。它不会按预期工作。