PHP web登录未保持用户登录。

我在我的一些网站上使用了这段PhP代码。但由于某种原因，我产生了一个小问题

现在，如果您尝试转到受此代码保护的页面，您将被重定向到index.php页面，其中有一个供您登录的论坛。一旦用户登录，它会将他们带到home.php，这一切都很好。但问题是，如果用户转到settings.php或其他页面，而不是主页，我会说40%的时间会将他们重定向回index.php页面重新登录。我以为这是时间的安排，但你可以登录并立即转到add.php，它会将你重定向到index.php，如果我返回一个页面（back to home.php）并单击另一个页面（example remove.php），它会允许我去那里。我不明白为什么它有时有效，有时无效

代码在我使用的所有页面上都是相同的，以请求下面的代码。 connection.php

<?php
    $con = new mysqli("localhost","****","********","********");
                if (mysqli_connect_errno()) {
                  echo "Failed to connect to MySQL: " . mysqli_connect_error();
                }
    ?>

<?php
if (!isset($_SESSION)) {
  session_start();
}
$MM_authorizedUsers = "9,10";
$MM_donotCheckaccess = "false";

// *** Restrict Access To Page: Grant or deny access to this page
function isAuthorized($strUsers, $strGroups, $UserName, $UserGroup) { 
  // For security, start by assuming the visitor is NOT authorized. 
  $isValid = False; 

  // When a visitor has logged into this site, the Session variable MM_Username set equal to their username. 
  // Therefore, we know that a user is NOT logged in if that Session variable is blank. 
  if (!empty($UserName)) { 
    // Besides being logged in, you may restrict access to only certain users based on an ID established when they login. 
    // Parse the strings into arrays. 
    $arrUsers = Explode(",", $strUsers); 
    $arrGroups = Explode(",", $strGroups); 
    if (in_array($UserName, $arrUsers)) { 
      $isValid = true; 
    } 
    // Or, you may restrict access to only certain users based on their username. 
    if (in_array($UserGroup, $arrGroups)) { 
      $isValid = true; 
    } 
    if (($strUsers == "") && false) { 
      $isValid = true; 
    } 
  } 
  return $isValid; 
}

$MM_restrictGoTo = "index.php?error=3";
if (!((isset($_SESSION['MM_Username'])) && (isAuthorized("",$MM_authorizedUsers, $_SESSION['MM_Username'], $_SESSION['MM_UserGroup'])))) {   
  $MM_qsChar = "?";
  $MM_referrer = $_SERVER['PHP_SELF'];
  if (strpos($MM_restrictGoTo, "?")) $MM_qsChar = "&";
  if (isset($QUERY_STRING) && strlen($QUERY_STRING) > 0) 
  $MM_referrer .= "?" . $QUERY_STRING;
  $MM_restrictGoTo = $MM_restrictGoTo. $MM_qsChar . "accesscheck=" . urlencode($MM_referrer);
  header("Location: ". $MM_restrictGoTo); 
  exit;
}
?>

限制访问.php

<?php
    $con = new mysqli("localhost","****","********","********");
                if (mysqli_connect_errno()) {
                  echo "Failed to connect to MySQL: " . mysqli_connect_error();
                }
    ?>

<?php
if (!isset($_SESSION)) {
  session_start();
}
$MM_authorizedUsers = "9,10";
$MM_donotCheckaccess = "false";

// *** Restrict Access To Page: Grant or deny access to this page
function isAuthorized($strUsers, $strGroups, $UserName, $UserGroup) { 
  // For security, start by assuming the visitor is NOT authorized. 
  $isValid = False; 

  // When a visitor has logged into this site, the Session variable MM_Username set equal to their username. 
  // Therefore, we know that a user is NOT logged in if that Session variable is blank. 
  if (!empty($UserName)) { 
    // Besides being logged in, you may restrict access to only certain users based on an ID established when they login. 
    // Parse the strings into arrays. 
    $arrUsers = Explode(",", $strUsers); 
    $arrGroups = Explode(",", $strGroups); 
    if (in_array($UserName, $arrUsers)) { 
      $isValid = true; 
    } 
    // Or, you may restrict access to only certain users based on their username. 
    if (in_array($UserGroup, $arrGroups)) { 
      $isValid = true; 
    } 
    if (($strUsers == "") && false) { 
      $isValid = true; 
    } 
  } 
  return $isValid; 
}

$MM_restrictGoTo = "index.php?error=3";
if (!((isset($_SESSION['MM_Username'])) && (isAuthorized("",$MM_authorizedUsers, $_SESSION['MM_Username'], $_SESSION['MM_UserGroup'])))) {   
  $MM_qsChar = "?";
  $MM_referrer = $_SERVER['PHP_SELF'];
  if (strpos($MM_restrictGoTo, "?")) $MM_qsChar = "&";
  if (isset($QUERY_STRING) && strlen($QUERY_STRING) > 0) 
  $MM_referrer .= "?" . $QUERY_STRING;
  $MM_restrictGoTo = $MM_restrictGoTo. $MM_qsChar . "accesscheck=" . urlencode($MM_referrer);
  header("Location: ". $MM_restrictGoTo); 
  exit;
}
?>

---

我会尝试删除对isset（$\u SESSION）的检查，我会假设该检查将返回true，并且从未调用SESSION\u start

$\u会话是PHP中注册的全局会话，PHP总是创建它。即使未调用session_start，并且对于空数组（），isset返回true，也可以修改此全局设置

请让我知道删除isset检查是否对您有效

只要简单地改变这个

if (!isset($_SESSION)) {
  session_start();
}

简单地说

session_start();

---

我猜它有时会起作用，而不是其他时候，因为您正在手动设置会话变量，然后检查它是否会起作用，但是，会话没有写入文件系统或数据库，因此页面有时会请求另一个脚本，也就是说它会失败，因为这是一个新的页面请求，并且会话没有在页面请求之间写入。

将

会话_start（）

放在页面顶部；不要先检查它。谢谢你，我现在正在尝试。。。我将公布结果。