PHP回应空的post数组，即使在使用params时也是如此

I am very new to php and am trying to create a REST API for my mobile backend. I'm using aws EC2 and have stored the following php file on my EC2 instance. But anyway, here is the code:

<?php include "FILE WITH DB INFO"; ?>
<?php

$connection = mysqli_connect(DB_SERVER, DB_USERNAME, DB_PASSWORD);

if (mysqli_connect_errno()) echo "Failed to connect to MySQL" . mysqli_connect_error();

$database = mysqli_select_db($connection, DB_DATABASE);

$user_username = $_POST['username'];
$user_name = $_POST['name'];
$user_email = $_POST['email'];

echo "BEFORE --- ";
var_dump($_POST);
echo "AFTER";

if (strlen($user_username) || strlen($user_name) || strlen($user_email)) {
    AddUser($connection, $user_username, $user_name, $user_email);
}


function AddUser($connection, $username, $name, $email) {
    $u = mysqli_real_escape_string($connection, $username);
    $n = mysqli_real_escape_string($connection, $name);
    $e = mysqli_real_escape_string($connection, $email);

   $query = "INSERT INTO 'users' ('username', 'name', 'email') VALUES ('$u', '$n', '$e');";
    if(!mysqli_query($connection, $query)) echo("ERROR ADDING USER DATA");
}

function VerifyUsersTable($connection, $dbName) {
    if(!TableExists("users", $connection, $dbName))
    {
            $query = "CREATE TABLE 'users' (
            'name' varchar(255),
            'username' varchar(255),
            'email' varchar(255),
            PRIMARY KEY ('username')
            )";

   if(!mysqli_query($connection, $query)) echo("ERROR CREATING TABLE");
    }
}
echo "MADE IT";
?>

My issue is that the var_dump($_POST); returns an empty array that looks like this: array(0) { }. This occurs even when I pass it three parameters like this: params: ?username=TestUser&name=TestName&email=TestEmail

actual request used: http://my_ec2_instance/Test.php?username=TestUser&name=TestName&email=TestEmail

What am I doing wrong?

EDIT: picture of postman screen POSTMAN SCREEN

This request:

http://my_ec2_instance/Test.php?username=TestUser&name=TestName&email=TestEmail

is a GET request, not POST.

Access it by: $_GET['name']

You should use $_GET[] . And to print all $_GET varaiables try:

print_r($_GET);

I prefer to use $_REQUEST. Just see this manual.

And access like it,

$_REQUEST['username'], $_REQUEST['name'], $_REQUEST['email']