如何在 php class 函数调用中使用 ajax 显示错误？

Question

Alright, this is probably super simple but I've been breaking my head over this all day and I cannot get it to work.

I have a page on which there is a function that addusers. To do this, I'm sending an AJAX call to handler.php which does some validation and sends an error if there is one, or success message if everything is ok.

In procedural PHP I can easily solve this problem by this approach:

NOTE:(My approach) This is just a demo code to show how ajax handle ERROR:SUCCESS messages

<p id="display_error"></p> // all success/error display here 

Ajax success

success: function(response) 
{
      if((response !== "") && ($.isNumeric(response))) {
        {
         //redirect in ajax success
         location.href = "http://localhost/manage/info.php?id="+ response;
        } 
      else {
             //this will display the custom error.
             $("#display_error").html("<p>" + response + "</p>"); //output: something went wrong!
           }
 }

PHP

if(num_rows > 0) {
    $conn = mysqli_connect();
    $query = "INSERT INTO MyGuests (firstname, lastname, email) VALUES ('$fname', '$lname', '$email')";
    $result = mysqli_query($conn, $query) or die ('Error Could Not Query');

    $id = mysqli_insert_id($result);

    echo $id;

    mysqli_close($conn);
} else { 
    echo 'something went wrong!';
}

But now I switch to classes...I and dont know how to display an error or success message using ajax in php functions. The problem is in function call. its a basics that PHP display the error or success message from where the actual function is called. In the below code the function is called from index page which is out of reach from ajax to fetch the success or error messages. Is there any better approach in php ajax error handling? I am new in this..love to see..

handler.php

function addUser($firstname, $lastname, $email)
{
    global $db;

   // prepare and bind
   $stmt = $db->prepare("INSERT INTO MyGuests (firstname, lastname, email) VALUES (?, ?, ?)");
   $stmt->bind_param("sss", $firstname, $lastname, $email);


   if($stmt->execute())
   {
      echo "New records created successfully";
   }else
   {
     echo "something went wrong!";
   }

   $stmt->close();


}

addUser('Navjot','singh','ns00@domain.com'); //calling from index.php page 

Answer 1

Use json_encode for the ajax call result. For example, echo json_encode(array('status' => 1, 'your value' => '')); or echo json_encode(array('status' => 0, 'error_msg' => ''));

And in your front-end, if you are using PHP then you can use json_decode(), if you are using javascript then you can use JSON.parse()