[英]How can I get a specific value from a database and compare it based on that value with PHP?
我的登录页面有问题。 在我的注册页面中,我询问用户他/她是学生还是老师。 这被放入数据库“ dbuploaden”。 当用户想要登录时,我需要从数据库中获取该信息,因为学生会看到与教师不同的主页。
这里的问题是,当我按下“登录”按钮时,我的页面似乎刷新了,没有出现错误或其他提示。 这是我使用的PHP代码:
<?php
session_start();
include_once 'connection.php';
if(isset($_SESSION['user'])!="")
{
//header("Location: home.php");
}
if(isset($_POST['btn-login']))
{
$email = mysql_real_escape_string($_POST['email']);
$upass = mysql_real_escape_string($_POST['pass']);
$res=mysql_query("SELECT * FROM tblgebruikers WHERE email='$email'");
$row=mysql_fetch_array($res);
if($row['password']==md5($upass))
{
if(mysql_query("SELECT * FROM tblgebruikers WHERE soortgebruiker = student")=="student")
{
die('Following connection error has occured: '.mysql_error());
$_SESSION['user'] = $row['gebruiker_id'];
header("Location: index.php");
}
if(mysql_query("SELECT * FROM tblgebruikers WHERE soortgebruiker = docent")=="docent")
{
die('Following connection error has occured: '.mysql_error());
$_SESSION['user'] = $row['gebruiker_id'];
header("Location: index2.php");
}
}
if($row['password']!=md5($upass))
{
echo "Foute gegevens. Probeer opnieuw.";
}
}
?>
谢谢
我刚开始从事网络编程时,几乎没有接受过培训,当然也没有老师来指导我。 学习起来可能比许多人一旦已经掌握了在哪里寻找答案以及如何阅读文档的困难要难得多。
首先,请,请,请,请使用mysqli
功能,而不是mysql
人。 此扩展程序已更新是有原因的。 或者,甚至更好的方法是,使用PDO或其他类似的适配器,这样,如果您决定超出此分配范围,则代码将更安全,更易于编写和以后维护。
此外,参数化查询! 立即开始使用它们,而忘了mysql_real_escape_string
对您来说将是一个美好的世界。
其次,请查看为什么使用md5哈希存储密码是个坏主意。 即使是这样的作业,您也应该练习使用安全和标准的编码方法,以便在前进时养成良好的习惯。
我已经删除了“ connection.php”文件的用法,并对数据库的结构进行了一些假设,以便为您提供有效的代码片段。 您可以使用以下代码在很多方面进行优化和改进,但确实可以达到预期的效果。
<?php
session_start();
//make sure you never do this in production
//you should store your connection usernames and passwords outside the web root
//to make unintentional disclosure of them harder
$mysqli = new mysqli( 'localhost', 'username', 'password', 'dpuploaden' );
if( mysqli_connect_errno() ){
//in real production code, this would be insecure as you shouldn't give away error information
//that could allow an attacker to gain more knowledge about your systems if at all possible
exit( printf( "Kan geen verbinding met de database: %s\n", mysqli_connect_error() ) );
}
if( isset( $_POST[ 'btn-login' ] ) ){
$email = $_POST[ 'email' ];
$upass = $_POST[ 'pass' ];
$id = NULL;
$password = NULL;
$soortgebruiker = NULL;
if( $stmt = $mysqli->prepare( 'SELECT `gebruiker_id`, `password`, `soortgebruiker` FROM `tblgebruikers` WHERE `email` = ?' ) ){
$stmt->bind_param( 's', $email );
$stmt->execute();
$stmt->bind_result( $id, $password, $soortgebruiker );
$stmt->fetch();
$stmt->close();
//please do not ever use md5 has a password hashing solution in real code
//look up the php function password_hash, or if you have PHP < 5.5.0 bcrypt
//for their proper usage, or better yet, seek out a library that implements
//this kind of login code and just use it
//roll your own is always a bad idea when it comes to security and, even with
//a lot of experience and information under your belt, it is all too easy to make mistakes
if( $row[ 'password' ] === md5( $upass ) ){
$_SESSION[ 'user' ] = $id;
$_SESSION[ 'soortgebruiker' ] = $soortgebruiker;
}
else
exit( "Foute gegevens. Probeer opnieuw." );
}
else{
exit( 'Fout retrieveing informatie.' );
}
}
if( isset( $_SESSION[ 'user' ] ) && $_SESSION[ 'user' ] != '' ){
if( $_SESSION[ 'soortgebruiker' ] === 'student' ){
header( "Location: index.php" );
exit;
}
else if( $_SESSION[ 'soortgebruiker' ] === 'docent' ){
header( "Location: index2.php" );
exit;
}
}
//output login page here
?>
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