PHP:确定会话过期时间

您可以使用$_SESSION和$_COOKIE的组合来实现这一点。

<?php
session_start();

$cookieName = 'user_id';

//Check if the session has started 
//or not
if (isset($_SESSION['started'])) {
  // Session exists, proceed with 
  //normal operation
  echo "Welcome back!";
} else {
 // Session does not exist, check 
 //if the cookie is present
 if (isset($_COOKIE[$cookieName])) 
  {
    // Cookie exists but session 
    //does not, meaning the session 
    //has expired
    echo "Your session expired";
   } else {
    // No session and no cookie, 
    //it's a new user
    // Set a new session and a new 
    //cookie
    $_SESSION['started'] = true;
    $uniqueId = uniqid();
    //Generate a unique ID as you 
    //prefer
    setcookie($cookieName, 
      $uniqueId, time() + (86400 * 
       30),"/"); // 30 days expiry
    echo "New user";
   }
}