RegisterUser.php

<?php

$response = array();
$response['response'] = 'false';



if($_SERVER["REQUEST_METHOD"]=="POST") {
    require 'config.php';
    require 'functions.php';

    $name = $_POST["name"];
    $username =  $_POST["username"];
    $email = $_POST["email"];
    $password = $_POST["password"];

    // Prevent SQl injections..
    $name = mysqli_real_escape_string($db_connect, $name);
    $username = mysqli_real_escape_string($db_connect, $username);
    $email = mysqli_real_escape_string($db_connect, $email);
    $password = mysqli_real_escape_string($db_connect, $password);

    // Hash entered passwords and add to database.
    $hashedPassword = call_user_func('hashPassword', $password);

    $checkUsername = mysqli_query($db_connect, "SELECT username FROM users WHERE username = '$username'");
    $checkEmail = mysqli_query($db_connect, "SELECT email FROM users WHERE email= '$email'");


        if(mysqli_num_rows($checkUsername) > 0 && mysqli_num_rows($checkEmail) > 0) {

            $response['response'] = 'usernameAndEmailExists';
            header('Context-Type: application/json');
            echo json_encode($response);

        } else if (mysqli_num_rows($checkUsername) > 0) {

            $response['response'] = 'usernameExists';
            header('Context-Type: application/json');
            echo json_encode($response);

        } else if (mysqli_num_rows($checkEmail) > 0) {

            $response['response'] = 'emailExists';
            header('Context-Type: application/json');
            echo json_encode($response);

        } else if (mysqli_num_rows($checkUsername) == 0 && mysqli_num_rows($checkEmail) == 0) {

            $query = ("INSERT INTO users(name, username, email, password) VALUES ('$name', '$username', '$email', '$hashedPassword')");


            if(mysqli_query($db_connect, $query)) {

                $response["response"] = 'successful';
                $query = ("SELECT * FROM users WHERE username = '$username'");
                $result = mysqli_query($db_connect, $query);
                $returnQuery = mysqli_fetch_assoc($result);
                $returnedId = $returnQuery['id'];
                $returnedScore = $returnQuery['score'];
                $response["id"] = $returnedId;
                $response["score"] = $returnedScore;
                header('Context-Type: application/json');
                echo json_encode($response);
            }


    }  else {

                $response["response"] = 'false';
    }


    mysqli_close($db_connect);

    }


?>