我使用PHP和bootstrap构建了一个简单的用户注册和登录系统。我是一名静态设计师，所以PHP对我来说是一个新手，我到目前为止都在努力学习语法和逻辑，但我很享受。我实际上从在线某处复制了PHP代码，但将其修改为我的项目。
用户登录后，他将被定向到他的个人资料页面profile.php
一旦进入个人资料页面，我希望它说欢迎＆＃34;名字＆＃34;。目前它说欢迎＆＃34;用户名＆＃34;。所以在这段代码的某处，我认为$ username变量正在会话中保存。
我已经读过如何做到这一点，我认为逻辑是 - 应该创建会话 - 凭证应该保存在会话内的数组中 - 然后你就这样调用firstname变量：
<?php echo $_SESSION['firstname']; ?>
这是我的login.php代码：
<?php include('../header/header.php') ?>
<div class="container headingsrow">
<div class="row">
<div class="col-6 offset-3">
<h2>Login</h2>
<p>Already have an account set up? Log in with your details below:</p>
<form method="post" action="login.php">
<?php include('errors.php'); ?>
<div class="form-group">
<input type="text" name="username" value="<?php echo $username; ?>" class="form-control" id="inputUsername" placeholder="Email address">
</div>
<div class="form-group">
<input type="password" name="password" value="<?php echo $username; ?>" class="form-control" id="inputPassword" placeholder="Password">
</div>
<button type="submit" class="btn btn-primary register" name="login_user">Login <i class="fas fa-sign-in-alt"></i></button>
<a href="#"><p>Forgotten your password? </p></a><br><br>
</form>
</div>
</div>
这是我的header.php代码：
<?php
session_start();
//After Login
$_SESSION['id'] = 1;
// initializing variables
$firstname = "";
$lastname = "";
$username = "";
$email = "";
$telnumber = "";
$addressline1 = "";
$addressline2 = "";
$city = "";
$postcode = "";
$errors = array();
// connect to the database
$db = mysqli_connect('localhost', 'root', '', 'registration');
// REGISTER USER
if (isset($_POST['reg_user'])) {
// receive all input values from the form
$firstname = mysqli_real_escape_string($db, $_POST['firstname']);
$lastname = mysqli_real_escape_string($db, $_POST['lastname']);
$username = mysqli_real_escape_string($db, $_POST['username']);
$email = mysqli_real_escape_string($db, $_POST['email']);
$telnumber = mysqli_real_escape_string($db, $_POST['telnumber']);
$addressline1 = mysqli_real_escape_string($db, $_POST['addressline1']);
$addressline2 = mysqli_real_escape_string($db, $_POST['addressline2']);
$city = mysqli_real_escape_string($db, $_POST['city']);
$postcode = mysqli_real_escape_string($db, $_POST['postcode']);
$password_1 = mysqli_real_escape_string($db, $_POST['password_1']);
$password_2 = mysqli_real_escape_string($db, $_POST['password_2']);
// form validation: ensure that the form is correctly filled ...
// by adding (array_push()) corresponding error unto $errors array
if (empty($firstname)) { array_push($errors, "First Name is required"); }
if (empty($lastname)) { array_push($errors, "Last Name is required"); }
if (empty($username)) { array_push($errors, "Username is required"); }
if (empty($email)) { array_push($errors, "Email is required"); }
if (empty($telnumber)) { array_push($errors, "Telephone number is required"); }
if (empty($addressline1)) { array_push($errors, "Address line 1 is required"); }
if (empty($addressline2)) { array_push($errors, "Address line 2 is required"); }
if (empty($city)) { array_push($errors, "City is required"); }
if (empty($postcode)) { array_push($errors, "Post code is required"); }
if (empty($password_1)) { array_push($errors, "Password is required"); }
if ($password_1 != $password_2) {
array_push($errors, "The two passwords do not match");
}
// first check the database to make sure
// a user does not already exist with the same username and/or email
$user_check_query = "SELECT * FROM users WHERE username='$username' OR email='$email' LIMIT 1";
$result = mysqli_query($db, $user_check_query);
$user = mysqli_fetch_assoc($result);
if ($user) { // if user exists
if ($user['username'] === $username) {
array_push($errors, "Username already exists");
}
if ($user['email'] === $email) {
array_push($errors, "email already exists");
}
}
// Finally, register user if there are no errors in the form
if (count($errors) == 0) {
$password = md5($password_1);//encrypt the password before saving in the database
$query = "INSERT INTO users (firstname, lastname, username, email, telnumber, addressline1, addressline2, city, postcode, password)
VALUES('$firstname', '$lastname', '$username', '$email', '$telnumber', '$addressline1', '$addressline2', '$city', '$postcode', '$password')";
mysqli_query($db, $query);
$_SESSION['username'] = $username;
$_SESSION['success'] = "You are now logged in";
header('location: index.php');
}
}
// ...
// LOGIN USER
if (isset($_POST['login_user'])) {
$username = mysqli_real_escape_string($db, $_POST['username']);
$password = mysqli_real_escape_string($db, $_POST['password']);
if (empty($username)) {
array_push($errors, "Username is required");
}
if (empty($password)) {
array_push($errors, "Password is required");
}
if (count($errors) == 0) {
$password = md5($password);
$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
$results = mysqli_query($db, $query);
if (mysqli_num_rows($results) == 1) {
$_SESSION['username'] = $username;
//$_SESSION['success'] = "You are now logged in" ;
header('location: profile.php');
}else {
array_push($errors, "Wrong username/password combination");
}
}
}
?>
<!doctype html>
<html lang="en">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<link rel="stylesheet" type="text/css" href="../assets/css/style.css">
<script defer src="https://use.fontawesome.com/releases/v5.0.8/js/all.js"></script>
<title>Prospect Job Vacancies</title>
</head>
<body>
<!-- start of Navbar -->
<div class="container menubg">
<div class="row">
<div class="col">
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="http://vacancies.prospect.local/index.php"><img src="../assets/img/prospect_logo.jpg" class="logo"></a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item">
<a href="http://vacancies.prospect.local/index.php"><button type="submit" name="home" class="btn btn-primary">Home <i class="fas fa-home"></i></i></button></a>
<!-- <a class="nav-link" href="http://vacancies.prospect.local/registration/register.php">Register <span class="sr-only">(current)</span></a> -->
</li>
<li class="nav-item">
<?php
if(isset($_SESSION['username'])){
echo "<a href=\"http://vacancies.prospect.local/registration/profile.php\"><button type=\"submit\" name=\"home\" class=\"btn btn-primary\">My Account <i class=\"far fa-user\"></i></button></a>";
}else{
echo "<a href=\"http://vacancies.prospect.local/registration/register.php\"><button type=\"submit\" name=\"home\" class=\"btn btn-primary\">Register <i class=\"fas fa-user-plus\"></i></i></i></button></a>";
}
;?>
</li>
<li class="nav-item">
<?php
if(isset($_SESSION['username'])){
echo "<a href=\"http://vacancies.prospect.local/logout.php\"><button type=\"submit\" name=\"logout\" class=\"btn btn-primary\">Logout <i class=\"fas fa-sign-in-alt\"></i></button></a>";
}else{
echo "<a href=\"http://vacancies.prospect.local/registration/login.php\"><button type=\"submit\" name=\"login\" class=\"btn btn-primary\">Login <i class=\"fas fa-sign-in-alt\"></i></button></a>";
}
;?>
<!-- <a class="nav-link" href="http://vacancies.prospect.local/registration/register.php">Register <span class="sr-only">(current)</span></a> -->
</li>
<!-- <a class="nav-link" href="http://vacancies.prospect.local/registration/register.php">Register <span class="sr-only">(current)</span></a> -->
</ul>
<span class="navbar-text">
<a href="https://www.prospect.org.uk/"><i class="fas fa-sign-out-alt"></i> Return to main Prospect website</a>
</span>
</div>
</nav>
<!-- //end of Navbar -->
</div>
</div>
</div>
<!-- end of top menu div -->
<div class="container-fluid jobbg">
<div class="row">
<div class="col">
<div class="container title">
<div class="row">
<div class="col">
<h1 class="jobheading">Job opportunities with Prospect</h1>
</div>
</div>
</div>
</div>
</div>
</div>
所以当我在我的profile.php代码中更改此部分时：
<?php echo $_SESSION['username']; ?>
到
<?php echo $_SESSION['firstname']; ?>
我收到此错误：
Welcome
Notice: Undefined index: firstname in
C:\xampp\htdocs\vacancies\registration\profile.php on line 46
array(2) { ["id"]=> int(1) ["username"]=> string(11) "bum@bum.com" }
最终我希望它说欢迎＆＃34;名字＆＃34;。
答案 0 :(得分：0)
所有这些意味着 $ _ SESSION ['firstname'] 未定义，在这种情况下，您忘记为 $ _ SESSION ['firstname'] 分配值用户登录。
你的header.php中的：
{{1}}
答案 1 :(得分：-1)
您尝试在此处添加$_SESSION['firstname']
if (count($errors) == 0) {
$password = md5($password);
$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
$results = mysqli_query($db, $query);
if (mysqli_num_rows($results) == 1) {
$_SESSION['username'] = $username;
$_SESSION['firstname'] = "HERE YOUR FIRST NAME";
// $_SESSION['success'] = "You are now logged in";
header('location: profile.php');
} else {
array_push($errors, "Wrong username/password combination");
}
}