Question

点击提交后，

登录表单错误500 嗨，大家好，我们在php课程中有一个小组作业，我们应该在PHP和MySQL中设计一个登录系统。我们编写了表单，PHP脚本，创建了数据库，并且一切正常，除了当您按下提交按钮时输入在数据库中指定的用户名和密码时，它使我们进入500内部错误页面。该代码位于/ login文件夹中名为index.php的文件中，它应授予对父文件夹中文件的访问权限。就是这样：

<?php
// Initialize the session
session_start();


// Check if the user is already logged in, if yes then redirect him to welcome page
if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){
    header("location:../accessgranted.php");
    exit;
}

// Include config file
require_once "db.php";

// Define variables and initialize with empty values
$username = $password = "";
$username_err = $password_err = "";
$username_ph = "Enter Username";
$password_ph = "Enter password";

// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){

    // Check if username is empty quoted th trim function because it caused the same 500 error when trying to run the login page
    if(empty/*(trim*/($_POST["username"]/*)*/)){
        $username_err = "Entrez votre nom d'utilisateur";
    } else{
        $username = trim($_POST["username"]);
    }

    // Check if password is empty
    if(empty/*(trim*/($_POST["password"]/*)*/)){
        $password_err = "Entrez votre mot de passe";
    } else{
        $password = trim($_POST["password"]);
    }

    // Validate credentials
    if(!empty($username) && !empty($password)){
        // Prepare a select statement
        $sql = "SELECT id, username, password FROM Users WHERE username = ?";

        if($stmt = mysqli_prepare($con, $sql)){

            // Bind variables to the prepared statement as parameters
            mysqli_stmt_bind_param($stmt, "s", $param_username);

            // Set parameters
            $param_username = $username;

            // Attempt to execute the prepared statement
            if(mysqli_stmt_execute($stmt)){


                // Store result
                mysqli_stmt_store_result($stmt);

                // Check if username exists, if yes then verify password
                if(mysqli_stmt_num_rows($stmt) == 1){                    
                    // Bind result variables
                    mysqli_stmt_bind_result($stmt, $id, $username, $hashed_password);

                    if(mysqli_stmt_fetch($stmt)){

                        if(password_verify($password, $hashed_password)){

                            // Password is correct, so start a new session
                            session_start();

                            // Store data in session variables
                            $_SESSION["loggedin"] = true;
                            $_SESSION["id"] = $id;
                            $_SESSION["username"] = $username;                            

                            // Redirect user to welcome page
                            header("location: ../accessgranted.php");

                        } else{
                            // Display an error message if password is not valid
                            $password_err = "The password you entered was not valid.";
                        }
                    }//added
                } else{
                    // Display an error message if username doesn't exist
                    $username_err = "No account found with that username.";
                }
            } else{
                echo "Oops! Something went wrong. Please try again later.";
            } 
        }

        // Close statement
        mysqli_stmt_close($stmt);
    }

    // Close connection
    mysqli_close($con);
}

?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Login</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
    <style type="text/css">
        body{ font: 14px sans-serif; }
        .wrapper{ width: 350px; padding: 20px; }
    </style>
</head>
<body>
   <center> 
        <h1>Connection</h1>
        <h2>Login Assignment</h2>
        <div class="wrapper">
        <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
            <div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
                <p align="left">Username</p>
                <input type="text" name="username" class="form-control" value="<?php echo $username; ?>" placeholder="<?= $username_ph?>">
                <span class="help-block"><?php echo $username_err; ?></span>
            </div>    
            <div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
                <p align="left">Password</p>
                <input type="password" name="password" class="form-control" placeholder="<?= $password_ph?>" align="left">
                <span class="help-block"><?php echo $password_err; ?></span>
            </div>
            <div class="form-group">
                <input type="submit" class="btn btn-primary" value="Login">
            </div>
            <p>Don't have an account? <a href="register.php">Sign up now</a>.</p>
        </form>
    </div>  </center>  
</body>
</html>

我们必须在周日之前移交它，以便您的帮助将不胜感激

Answer 1

每当您遇到500错误时，由于忘记了逗号，点，方括号，SQL查询等等，您在语法上都会犯错误

Answer 2

检查error_reporting文件中的display_errors，display_startup_errors和php.ini设置。它们应分别设置为E_ALL和"On"。您还可以在脚本的开头更改这些设置（display_startup_errors除外）以在运行时进行设置。

error_reporting(E_ALL);
ini_set('display_errors', 'On');

然后，重新启动服务器。

并检查脚本中引起的错误。

登录表单，单击提交后错误500

2 个答案: