php - 当我尝试将 longtext 字段作为数据库查询的 Json 结果时，为什么整个页面会变为空白？

Question

我试图从我的数据库表中获取一个 longtext 变量，并将结果作为 json 变量，每次我有一个空白页时都没有给我任何错误。这是我的代码：

<?php
require_once 'include/DB_Functions.php';
$db = new DB_Functions();

// json response array
$response = array("error" => FALSE);

if (isset($_GET['email']) && isset($_GET['password'])) {

// receiving the post params
$email = $_GET['email'];
$password = $_GET['password'];

// get the user by email and password
$user = $db->getUserByEmailAndPassword($email, $password);

if ($user != false) {
    // use is found
    $response["error"] = FALSE;
    $response["user"]["firstname"] = $user["firstname"];
    $response["user"]["lastname"] = $user["lastname"];
    $response["user"]["email"] = $user["email"];
    $response["user"]["created_at"] = $user["created_at"];
    $response["user"]["description"] = $user["description"];
    echo json_encode($response);
} else {
    // user is not found with the credentials
    $response["error"] = TRUE;
    $response["error_msg"] = "Login credentials are wrong. Please try again!";
    echo json_encode($response);
}
} else {
// required post params is missing
$response["error"] = TRUE;
$response["error_msg"] = "Required parameters email or password is missing!";
echo json_encode($response);
}
?>

我的问题是“描述”行（长文本），

先感谢您