Please note that this example is vulnerable to injection and uses plain-stored passwords...
(PHP 5, PHP 7, PHP 8)
mysqli::real_query -- mysqli_real_query — Ejecuta una consulta SQL
Estilo orientado a objetos
Estilo por procedimientos
Ejecuta una sola consulta contra la base de datos cuyo resultado puede ser recuperado o almacenado mediante las funciones mysqli_store_result() o mysqli_use_result().
Con el fin de determinar si una consulta dada debe devolver un conjunto de resultados o no, ver mysqli_field_count().
link
Sólo estilo por procediminetos: Un identificador de enlace devuelto por mysqli_connect() o mysqli_init()
query
La consulta como un string.
Los datos dentro de la consulta deben estar apropiadamente escapados.
Devuelve true
en caso de éxito o false
en caso de error.
Please note that this example is vulnerable to injection and uses plain-stored passwords...
Well, we don't know if $password is in plain text because it was never defined in the example.
New passwords should be stored using
<?php
$crypt_pass = password_hash($password, PASSWORD_DEFAULT);
?>
Where PASSWORD_DEFAULT = BCRYPT algorithm
Then to compare a user entered password to a database stored password, we use:
<?php
$valid = password_verify($password, $crypt_pass);
?>
Which returns true or false.
As for being vulnerable to injection, this is true. To avoid this, use sprintf() or vsprintf() to format the query and inject the values using mysqli::real_escape_string, like so:
<?php
$vals = [$db->real_escape_string($username), $db->real_escape_string($password)];
$query = vsprintf("Select * From users Where username='%s' And password='%s'", $vals);
$result = $db->real_query($query);
?>
Straightforward function - simply connect to the database and execute a query, similar to this function bellow.
<?php
function check_password($username, $password) {
// Create connection
$db = new mysqli('localhost','database_user','database_pass','database_name');
// Check for errors
if($db->connect_errno){
echo $db->connect_error;
}
// Execute query
$result = $db->real_query("Select * From users Where username='$username' And password='$password'");
// Always check for errors
if($db->connect_errno){
echo $db->connect_error;
}
return $result == true;
}
?>
Very easy.
Replace database_user, database_pass and database_name with the proper names, and the text inside real_query with your actual query.
Don't forget the quotes on either side (except for numbers, there you can omit them) otherwise it won't work. Hope that helps someone.