feat: cartdetail_query script

server/controllers/cartdetail_query.php

+<?php
+    session_start();
+    require_once "connect_database.php";
+    global $conn; $conn = connect_database();
+    if ($_SERVER["REQUEST_METHOD"] == "POST") {
+        global $conn;
+        $query = "SELECT * FROM `cart` WHERE `cart_username` = (?))
+        ";
+        $cart_username = $_SESSION["username"];
+
+        $stmt = $conn->prepare($insert_query);
+        if (!$stmt) {
+            die("Error in query preparation". $conn->error);
+        }
+
+        $stmt->bind_param("s", $cart_username);
+        $result = $stmt->execute();
+        $resultSet = $stmt->get_result();
+
+
+        if (!$result) {
+            $response = array("success" => "false", "message" => $stmt.error);
+            die ("Error in query execution: " . $stmt->error);
+        } else {
+            $response = array("success" => "true", "message" => "item has been added", "data" => $resultSet->fetch_all(MYSQLI_ASSOC));
+        }
+        echo json_encode($response);
+        mysqli_close($conn);
+    }
+?>
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