PHP无法设置会话变量
[英]PHP Unable to set a session variable
问题描述
From a login page I am capturing the user and password values: 
从登录页面中，我正在捕获用户和密码值：
<?php
session_start();
$error='';
$rows = 0;
if (isset($_POST['submit'])) {
$username=$_POST['username'];
$password=$_POST['password'];
$mysqli = new mysqli("localhost","xxxxx","xxxxx","xxxxxxx");
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$username = stripslashes($username);
$password = stripslashes($password);
$username = $mysqli->real_escape_string($username);
$password = $mysqli->real_escape_string($password);
$query = "select count(*) from login where password='$password' AND username='$username'";
if ($stmt = $mysqli->prepare($query)) {
$stmt->execute();
$stmt->store_result();
$rows = $stmt->num_rows;
$stmt->close();
}
}
$mysqli->close();
if ($rows == 1) {
$_SESSION['login_user']=$username;
header("location: profile.php");
} else {
header("location: login.php");
$error = "Username or Password is invalid";
}
?>
My profile.php script is something like below: 我的profile.php脚本如下所示：
<?php
include('session.php');
?>
<!DOCTYPE html>
<html>
<head>
<title>Your Home Page</title>
<link href="style.css" rel="stylesheet" type="text/css">
</head>
<body>
<div id="profile">
<b id="welcome">Welcome : <i><?php echo $login_session; ?></i></b>
<b id="logout"><a href="logout.php">Log Out</a></b>
</div>
</body>
</html>
And session.php 和session.php
<?php
if(!isset($_SESSION['login_user'])){
header('Location: login.php');
}
?>
My code flow is like when the login form is submitted the validate_login.php source code will verify the details from the user. 我的代码流程就像提交登录表单时一样，validate_login.php源代码将验证用户的详细信息。 In case the details are correct a profile.php page would be displayed or back again to login page. 如果详细信息正确，将显示profile.php页面或再次返回登录页面。
I am having 3 difficulties; 我有3个困难；
- How to debug PHP scripts? 如何调试PHP脚本？
- Why my code is going back to login page again - I have tested by hard coding wrong undefined variable (forcing a dump) - I found that the row is found as it enters in if condition which defines the session variable [if ($rows == 1)] 为什么我的代码又回到登录页面-我已经通过硬编码测试了错误的未定义变量（强制转储）-我发现在进入if时定义了会话变量[if（$ rows = = 1）]
- Is there any other way we can verify a session - basically only a logged in user should see the further pages? 还有什么其他方法可以验证会话-基本上只有登录的用户才能看到其他页面？
3 个解决方案
解决方案1
1 已采纳 2014-12-18 10:06:09
you have no session right now in youre session.php 您在session.php中没有会话
<?php
if(!isset($_SESSION['login_user'])){
header('Location: login.php');
}
?>
You need to add session_start(); 您需要添加session_start();
So u will get 所以你会得到
<?php
session_start();
if(!isset($_SESSION['login_user'])){
header('Location: login.php');
}
?>
For security its better to use prepared prepared statements . 为了安全起见，最好使用准备prepared statements准备prepared statements 。 For error handelings, try to make something is there really a session ?. 对于错误处理，请尝试使某个会话真正存在？
if(session_id() == '' || !isset($_SESSION)) {
// session isn't started
echo "No session";
}
解决方案2
1 2014-12-18 10:09:42
Your session.php should be 您的session.php应该是
empty()is essentially the concise equivalent to!isset($var) || $var == falseempty()本质上等同于!isset($var) || $var == false!isset($var) || $var == false.!isset($var) || $var == false
<?php
session_start();
if(empty($_SESSION['login_user'])){
header('Location: login.php');
}
?>
include session.php to your script and any other page that is for registered users 将session.php包含到您的脚本和其他任何供注册用户使用的页面中
<?php
include_once('session.php');
$error='';
$rows = 0;
if (isset($_POST['submit'])) {
$username=$_POST['username'];
$password=$_POST['password'];
$mysqli = new mysqli("localhost","xxxxx","xxxxx","xxxxxxx");
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$username = stripslashes($username);
$password = stripslashes($password);
$username = $mysqli->real_escape_string($username);
$password = $mysqli->real_escape_string($password);
$query = "select count(*) from login where password='$password' AND username='$username'";
if ($stmt = $mysqli->prepare($query)) {
$stmt->execute();
$stmt->store_result();
$rows = $stmt->num_rows;
$stmt->close();
}
}
$mysqli->close();
if ($rows == 1) {
$_SESSION['login_user']=$username;
header("location: profile.php");
} else {
header("location: login.php");
$error = "Username or Password is invalid";
}
?>
解决方案3
0 2014-12-18 10:21:33
Call session_start() function, before use any session variable. 在使用任何会话变量之前，请调用session_start（）函数。
If you get warning such as : Warning: Cannot modify header information - headers already sent (output started at script:line), then use @ suppression operator 如果收到诸如以下警告：警告：无法修改标头信息-标头已发送（输出从script：line开始），则使用@抑制运算符
@session_start() //@ for error suppression
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