PHP login system works on local but doesn't work on Hostgator PHP 7.2

Question

PHP login system works on local but doesn't work on Hostgator PHP 7.1. My local is PHP 7.2

I've built out a fully working portal on my local machine. I can CRUD on my local machine. As soon as I put it on the server online, the login system doesn't work. I still can register new users as the user info populates in the DB, so its not a DB config issue. I am getting these errors:

Warning: mysqli_stmt_bind_param(): Number of variables doesn't match number of parameters in prepared statement in .....

Fatal error: Uncaught Error: Call to undefined function mysqli_stmt_get_result() in ....

I have spent 5 hours trying to figure out why it won't work on the Hostgator server but will work on my local.

Here is my code:

if(isset($_POST['loginSubmit'])){

    //include connection configs
    require '../../db_configs.php';

    $email = mysqli_real_escape_string($conn, $_POST['email']);
    $password = mysqli_real_escape_string($conn, $_POST['password']);   

    if(empty($email || $password )){

        header("Location: ../../../portalSignIn.php?signin=fieldsempty");
        exit();

    }
    else
    {
        //user email query
        $sqlEmail = "SELECT * FROM users WHERE email='$email'";
        $emailResult = mysqli_query($conn, $sqlEmail);
        $stmt = mysqli_stmt_init($conn);

        //SQL Error
        if(!mysqli_stmt_prepare($stmt, $sqlEmail)){

            header("Location: ../../../portalSignIn.php?signin=SQL_FAILED");
            exit();

        }
        if(mysqli_num_rows($emailResult) == 0){

            //email doesn't exist
            header("Location: ../../../portalSignIn.php?signin=incorrectemail");
            exit();
        }
        else
        {   
            //bind data if email exists
            mysqli_stmt_bind_param($stmt, "s", $email);
            mysqli_stmt_execute($stmt);
            $result = mysqli_stmt_get_result($stmt);

            if($row = mysqli_fetch_assoc($result)){....

Its breaking at this point --> mysqli_stmt_bind_param($stmt, "s", $email);

I've looked into https://www.plus2net.com/php_tutorial/mysqli_mysqlnd.php and Hostagtor doesn't have these settings. And I have used mysqli_stmt_bind_param() successfully on the sign up page.

I am learning from an online tutorial as back end is new to me. — phpNetSvelteLover, May 01 '20 at 11:36
Also, I want to know why it works fine on the local machine but not when I put it up on the server — phpNetSvelteLover, May 01 '20 at 11:41
Also it looks like your hosting server might be misconfigured. `Call to undefined function mysqli_stmt_get_result` sounds like you have mysqlnd switched off. — Dharman, May 02 '20 at 21:57
'mysqlnd switched off' -- I've looked in Hostgator Cpanel and I cannot find anywhere to change this setting — phpNetSvelteLover, May 03 '20 at 05:00
After doing more research, Hostgator doesn't allow php-mysqlnd for shared webhosting. It is only available for dedicated and VPS customers. I am on a shared plan, so I have to use a different method. https://www.hostgator.com/help/article/compatible-technologies — phpNetSvelteLover, May 03 '20 at 06:42
LOL - indeed. But with your help I have found a better way to do things — phpNetSvelteLover, May 03 '20 at 10:39

score 1 · Answer 1 · answered May 01 '20 at 11:24

You have plenty of mistakes in your code. Let me explain a few of them to you.

Don't escape your variables using mysqli_real_escape_string(). Just don't use this function at all.
empty($email || $password ) is going to check a boolean value. This does not make much sense. Remove the empty call and check the negation. If neither $email nor $password then one of them is empty.
Don't use mysqli_query. You are going to prepare a statement, so do not call this function. Also you need to parameterized the SQL. Use ? as placeholder for the value.
mysqli_num_rows in this place would throw an error. You don't need this function at all. If you wanted to use it you would need to pass the as a parameter the output of get_result()
To fetch values using prepared statement you need to prepare/bind/execute/get_result. Only then you can fetch a row if it exists. If nothing is returned then $record will be null.

if (isset($_POST['loginSubmit'])) {

    //include connection configs
    require '../../db_configs.php';

    $email = $_POST['email'];
    $password = $_POST['password'];

    if (!$email || !$password) {
        header("Location: ../../../portalSignIn.php?signin=fieldsempty");
        exit();
    } else {
        //user email query
        $sqlEmail = "SELECT * FROM users WHERE email=?";
        $stmt = $con->prepare($sqlEmail);
        $stmt->bind_param('s', $email);
        $stmt->execute();
        $result = $stmt->get_result();
        $record = $result->fetch_assoc();
        if (!$record) {
            //email doesn't exist
            header("Location: ../../../portalSignIn.php?signin=incorrectemail");
            exit();
        } else {
            // handle your data here
        }
    }
}

And as always don't forget to enable mysqli error reporting. See How to get the error message in MySQLi?

Thanks for the code review but the focus of this thread is why this works on my local but not on the Hostgator server. — phpNetSvelteLover, May 02 '20 at 21:52
If it works on your local machine then I am surprised. You probably got lucky. However, I can't imagine how it could possibly work. It should throw a bunch of errors and die a painful death. — Dharman, May 02 '20 at 21:53
I put your code into my code and it works on my local. However, once I deploy that to Hostgator, I get "Uncaught Error: Call to undefined method mysqli_stmt::get_result()" now. Hostgator doesn't have tick boxes for me like in this website example: https://www.plus2net.com/php_tutorial/mysqli_mysqlnd.php — phpNetSvelteLover, May 03 '20 at 05:21

score 0 · Answer 2 · edited May 03 '20 at 11:37

The issue I am having is because Hostgator does not have mysqlnd available for shared hosting users but only those with VPS or dedicated servers:

https://www.hostgator.com/help/article/compatible-technologies

It can be enabled for other users and instructions can be done following this tutorial:

https://www.plus2net.com/php_tutorial/mysqli_mysqlnd.php

This was a learning lesson, especially in getting to know your webhost.

PHP login system works on local but doesn't work on Hostgator PHP 7.2

2 Answers2