添加验证码以形成php / mysql

Question

I want to add Google captcha to my php form. The form adds data to my mysql database. How can I add the two parts of code together so the form checks first the captcha and after it's checked, then send it.

$servername = "";
$username = "";
$password = "";
$database = "";


$conn = new mysqli($servername, $username, $password, $database);

if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
} 


    $email = $_SESSION['userName'];
    $contact = $_POST['naar'];
    $address = $_POST['bericht'];


$sql = "INSERT INTO messages (to_user, from_user, message)
        VALUES ('".$contact."', '".$email."', '".$address."')";


$conn->close();






  if($_SERVER["REQUEST_METHOD"] === "POST")
   {
    //form submitted

    //check if other form details are correct

    //verify captcha
    $recaptcha_secret = "xxxxxxxxxxxxxx";
    $response = file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=".$recaptcha_secret."&response=".$_POST['g-recaptcha-response']);
    $response = json_decode($response, true);
    if($response["success"] === true)
    {
        echo "Logged In Successfully";
    }
    else
    {
        echo "You are a robot";
    }
}

Answer 1

As @Dagon and @Marc B have suggested in the comments above, try this:

$servername = "";
$username = "";
$password = "";
$database = "";

  if($_SERVER["REQUEST_METHOD"] === "POST")
   {
    //form submitted

    //check if other form details are correct

    //verify captcha
    $recaptcha_secret = "xxxxxxxxxxxxxx";
    $response = file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=".$recaptcha_secret."&response=".$_POST['g-recaptcha-response']);
    $response = json_decode($response, true);
    if($response["success"] === true)
    {

        //$conn = new mysqli($servername, $username, $password, $database);
        try{
               $db = new PDO('mysql:host='.$servername.';dbname='.$database,$username,$password);
               $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        }
        catch(PDOException $e){
              echo "Error connecting to DB";
              echo $e->getMessage();
              exit();
        }

        if ($conn->connect_error) {
            die("Connection failed: " . $conn->connect_error);
        } 

        $email = $_SESSION['userName'];
        $contact = $_POST['naar'];
        $address = $_POST['bericht'];


        $sql_pdo = "INSERT INTO messages (to_user, from_user, message)
                VALUES (:contact, :email, :address)";

        $stmt = $conn->prepare($sql_pdo);

        try {
             $result = $stmt->execute( array(
                ':contact' => $contact,
                ':email' => $email,
                ':address' => $address
                ));
             if ( count($result) > 0 ) {
                // Insert has gone well. Do your things here.
                echo "Logged In Successfully";
             }
             else {
                 // Insert error. Report, check, ...
             }
        }
        catch(PDOException $e){
            echo 'could not insert in DB';
            echo 'Error: ' . $e->getMessage();
            return false;
        }

        $conn->close();
    }
    else
    {
        echo "You are a robot";
    }
}