Quiero insertar algunos valores de otros sitios web a la mía DB. No quiero compartir DB credenciales con los demás. Así que, estoy pidiendo una ayuda para desarrollar una API para mi sitio. Necesito el único de inserción. Mi aplicación web está desarrollado con PHP-MySQL.

Este es el código que he utilizado:

database.php

<?php
        class Database{

        // specify your own database credentials
        private $host = "localhost";
        private $db_name = "testdatabase";
        private $username = "root";
        private $password = "";
        public $conn;

        // get the database connection
        public function getConnection(){

            $this->conn = null;

            try{
                $this->conn = new PDO("mysql:host=" . $this->host . ";dbname=" . $this->db_name, $this->username, $this->password);
                $this->conn->exec("set names utf8");
            }catch(PDOException $exception){
                echo "Connection error: " . $exception->getMessage();
            }

            return $this->conn;
        }
    }

?>

product.php

class Product{

// database connection and table name
private $conn;
private $table_name = "products";

// object properties
public $id;
public $name;
public $description;
public $price;
public $category_id;
public $category_name;
public $created;

// constructor with $db as database connection
public function __construct($db){
    $this->conn = $db;
}
// create product
function create(){

    // query to insert record
    $query = "INSERT INTO
                " . $this->table_name . "
            SET
                name=:name, price=:price, description=:description, category_id=:category_id, created=:created";

    // prepare query
    $stmt = $this->conn->prepare($query);

    // sanitize
    $this->name=htmlspecialchars(strip_tags($this->name));
    $this->price=htmlspecialchars(strip_tags($this->price));
    $this->description=htmlspecialchars(strip_tags($this->description));
    $this->category_id=htmlspecialchars(strip_tags($this->category_id));
    $this->created=htmlspecialchars(strip_tags($this->created));

    // bind values
    $stmt->bindParam(":name", $this->name);
    $stmt->bindParam(":price", $this->price);
    $stmt->bindParam(":description", $this->description);
    $stmt->bindParam(":category_id", $this->category_id);
    $stmt->bindParam(":created", $this->created);

    // execute query
    if($stmt->execute()){
        return true;
    }

    return false;

}

Create.php

<?php
// required headers
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");
header("Access-Control-Allow-Methods: POST");
header("Access-Control-Max-Age: 3600");
header("Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With");

// get database connection
include_once '../config/database.php';

// instantiate product object
include_once '../objects/product.php';

$database = new Database();
$db = $database->getConnection();

$product = new Product($db);

// get posted data
$data = json_decode(file_get_contents("php://input"));

// make sure data is not empty
if(
    !empty($data->name) &&
    !empty($data->price) &&
    !empty($data->description) &&
    !empty($data->category_id)
){

    // set product property values
    $product->name = $data->name;
    $product->price = $data->price;
    $product->description = $data->description;
    $product->category_id = $data->category_id;
    $product->created = date('Y-m-d H:i:s');

    // create the product
    if($product->create()){

        // set response code - 201 created
        http_response_code(201);

        // tell the user
        echo json_encode(array("message" => "Product was created."));
    }

    // if unable to create the product, tell the user
    else{

        // set response code - 503 service unavailable
        http_response_code(503);

        // tell the user
        echo json_encode(array("message" => "Unable to create product."));
    }
}

// tell the user data is incomplete
else{

    // set response code - 400 bad request
    http_response_code(400);

    // tell the user
    echo json_encode(array("message" => "Unable to create product. Data is incomplete."));
}
?>

Cuando estoy comprobando con el CARTERO no consiguiendo los datos. cómo integrar esta con otro sitio? y por qué esto no está tomando el valor?