<?php
session_start();

if(isset($_SESSION["id"]) && empty($_SESSION["id"]) == false) {
    $dsn = "mysql:dbname=blog;host=127.0.0.1";
    $dbuser = "root";
    $dbpass = "";

    try {
        $db = new PDO($dsn, $dbuser, $dbpass);

        $id_usuario = $_SESSION["id"];

        $sql = $db->query("SELECT * FROM usuarios WHERE id = ".$id_usuario);

        if($sql->rowCount() > 0) {
            $dado = $sql->fetch();

            echo "O usuário do cara é: ".$dado["email"];
        } else {
            header("Location: login.php");
        }

    } catch(PDOException $e) {
        header("Location: login.php");
    }
} else {
    header("Location: login.php");
}

?>