my project in lamp not worked when i try to connect to database

Question

i recently installed lamp on ubuntu and now i got problems with them (i think that can not connected to database)

I did the following tests :

1. i tested mysql with call phpMyAdmin and that's done :

phpMyAdmin screanShot

2. i tested php with phpInfo and that's done too :

phpInfo screanshot

3. i tested simple code for to test the database connection

my simple code this is :

<?php
//phpinfo();

$servername = "localhost";
$username = "root";
$password = "3cret";

// Create connection
$conn = new mysql($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
   die("Connection failed: " . $conn->connect_error);
} 
echo "Connected successfully";

?>

And the result was:

The localhost page isn’t working

localhost is currently unable to handle this request. 500

Answer 1

There's either an error within your mod_php or your general PHP setup, I owuld also advise using mysqli over mysql as it is much better, use this code:

<?php
$conn = mysqli_connect("localhost","root","3cret","database_name");

// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }
?>

Answer 2

This problem was due to disabled virtual Directory Support and that's solved with this command :

sudo chmod -R 755 /var/www

Answer 3

Solution: In config/settings.inc.php

Replace this line:

define('_PS_CACHE_ENABLED_', '1');

with this:

define('_PS_CACHE_ENABLED_', '0');

Enjoy!