Trying to fetch results from a query as a PDO Object in PHP

Question

Problem: so whenever i try to login it returns the following error: Notice: Trying to get property 'user_id' of non-object in /butler/Classes/users/users.php on line 191

This happens cause the fetch method where I try to retrieve the user_id from the table comes empty, although the fetchColumn() functions shows that 1 row is found in the query.

I already checked the database table and the naming is correct. Also the html form is passing the parameters correctly that why I didn't posted that part of the code.

login page php

if (!empty($_POST['btnLogin'])) {

    $username = trim($_POST['username']);
    $password = trim($_POST['password']);

    if ($username == "") {
        $login_error_message = 'Username field is required!';
    } else if ($password == "") {
        $login_error_message = 'Password field is required!';
    } else {
        $user_id = $app->Login($username, $password); // check user login
        if($user_id > 0)
        {
            $_SESSION['user_id'] = $user_id; // Set Session
            header("Location: dashboard/layout.php"); // Redirect user to the profile.php
        }
        else
        {
            $login_error_message = 'Invalid login details!';
        }
    }
}

function login

public function Login($username, $pass)
        {
            try {
                $db = DB();
                $query = $db->prepare("SELECT user_id FROM start_users WHERE (user_start= :username) AND (psw= :pass) ");
                $query->bindParam("username", $username, PDO::PARAM_STR);
                //$enc_password = hash('sha256', $password);
                $query->bindParam("pass", $pass, PDO::PARAM_STR);
                $query->execute();
                if ($query->fetchColumn() > 0) {
                    $result = $query->fetch(PDO::FETCH_OBJ);
                    echo 'resultado'.$result.'   ';
                    print_r($query->errorInfo());

                    return $result->user_id;
                } else {
                    return false;
                }
            } catch (PDOException $e) {
                exit($e->getMessage());
            }
        }

**Never store passwords in clear text or using MD5/SHA1!** Only store password hashes created using PHP's [`password_hash()`](https://php.net/manual/en/function.password-hash.php), which you can then verify using [`password_verify()`](https://php.net/manual/en/function.password-verify.php). Take a look at this post: [How to use password_hash](https://stackoverflow.com/q/30279321/1839439) and learn more about [bcrypt & password hashing in PHP](https://stackoverflow.com/a/6337021/1839439) — Dharman, Aug 09 '19 at 17:03

score 2 · Accepted Answer · answered Aug 09 '19 at 15:07

2

Your call to

if ($query->fetchColumn() > 0) {

is retrieving the row and so the next call to

$result = $query->fetch(PDO::FETCH_OBJ);

is trying to read the another row, which I assume doesn't exist.

You should instead just make the one call

if ($result = $query->fetch(PDO::FETCH_OBJ)) {

I would also suggest the you look into How to use password_hash as your current method is using plain passwords which aren't recommended.

answered Aug 09 '19 at 15:07

Nigel Ren

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I just wanted to add a validation that in fact a row is returned in the query. Is this necessary? Or can I just fetch and save the result in variable. Also thanks for the password_hash ideia, I'm going to use it, but first I'm trying to achieve this with a text-plain password – Luis Luis Maia Maia Aug 09 '19 at 15:10
The validation is done by checking that `$result` contains something, `fetch()` will return `false` on failure. – Nigel Ren Aug 09 '19 at 15:11
Yeah you're right, I'm gonna do that. Now it returns the following error that `Object of class stdClass could not be converted to string`. I'm sure that the column I'm trying ti retrieve is of type `int`, could that be the problem? – Luis Luis Maia Maia Aug 09 '19 at 15:16
1

Your line `echo 'resultado'.$result.' ';` is most likely the issue, try (for debugging) using `print_r($result);` – Nigel Ren Aug 09 '19 at 15:19

Trying to fetch results from a query as a PDO Object in PHP

1 Answers1