Php、MySql 和 Webform

Question

我已经尝试解决这个问题两天多了，我正在遵循 YouTube 教程，并为我的 Android 应用程序进行基本登录，但在此之前我想测试 .php 脚本。

我认为当我按下登录按钮时应该会成功，但我收到无效的凭据，并且我知道用户名和密码是正确的

下面是我的login.php脚本。

require("config.inc.php");

if (!empty($_POST)) {
    //gets user's info based off of a username.
    $query = "SELECT id, username, passwrd
            FROM application_users
            WHERE
                username = :username
        ";
    $query_params = array(
        ':username' => $_POST['username']
    );

    try {
        $stmt   = $db->prepare($query);
        $result = $stmt->execute($query_params);
    }
    catch (PDOException $ex) {
        // For testing, you could use a die and message.
        //die("Failed to run query: " . $ex->getMessage());

        //or just use this use this one to product JSON data:
        $response["success"] = 0;
        $response["message"] = "Database Error1. Please Try Again!";
        die(json_encode($response));

    }

    //This will be the variable to determine whether or not the user's information is correct.
    //we initialize it as false.
    $validated_info = false;

    //fetching all the rows from the query
    $row = $stmt->fetch();
    echo $row;
    if ($row) {
        //if we encrypted the password, we would unencrypt it here, but in our case we just
        //compare the two passwords
        if ($_POST['password'] === $row['password']) {
            $login_ok = true;
        }
    }

    // If the user logged in successfully, then we send them to the private members-only page
    // Otherwise, we display a login failed message and show the login form again
    if ($login_ok) {
        $response["success"] = 1;
        $response["message"] = "Login successful!";
        die(json_encode($response));
    } else {
        $response["success"] = 0;
        $response["message"] = "Invalid Credentials!";
        die(json_encode($response));
    }
} else {
?>
    <h1>Login</h1>
    <form action="login.php" method="post">
        Username:<br />
        <input type="text" name="username" placeholder="username" />
        <br /><br />
        Password:<br />
        <input type="password" name="password" placeholder="password" value="" />
        <br /><br />
        <input type="submit" value="Login" />
    </form>
    <a href="register.php">Register</a>
    </form>
<?php

}？>

因此，当脚本加载并且我从远程 MYSQL 服务器输入值时，该消息将作为无效凭据返回。我只是想在转到 android 部分之前确保我的登录成功，这将是本身就是一件大事。

Answer 1

我还没有机会用真实的数据库来测试它，但这应该可行。您仍然需要在文件顶部添加 require("config.inc.php");，并且我添加了自定义数据库连接。我还使用 PDO，因此查询可能看起来与您目前使用的有所不同。

<?php
// Database connection
try
{
    $db = new PDO('mysql:host=localhost;dbname=mydatabase', 'myusername', 'mypassword');
    $db->exec('SET CHARACTER SET UTF8');
}
catch (Exception $e)
{
    //Message in case of error when connecting to the database
    die('Erreur : ' . $e->getMessage());
}
// *** End database connection




$username = ""; // Initialize value in order to keep its value so the user can still see it in his form

if (isset($_POST['login'])) { // if the "login" button is pressed
    $username = $_POST['username']; // retrieve username value from the form
    $password = $_POST['password']; // retrieve password value from the form

    /* 
    *   If a username is unique then a way to do it is to count how many times
    *  the couple with this username and this password appears in our database.
    */
    $query = $db->prepare("SELECT COUNT(*) userAmount ".
                            "FROM application_users ".
                            "WHERE username = $username ".
                            "AND password = $password;");

    $query->execute();
    $query->closeCursor();

    $resultAmount = $query->fetch();
    if ($resultAmount['userAmount'] == 0){ // If the couple username-password is unfound
        $message = "Username or password unknown";
    } else {
        $message("Login successful");
    }
}
?>


<h1>Login</h1>
<form action="login.php" method="post">
    Username:<br />
    <input type="text" name="username" placeholder="username" value="<?php echo($username); ?>" />
    <br/><br/>
    Password:<br/>
    <input type="password" name="password" placeholder="password" value="" />
    <br/><br/>
    <input type="submit" name="login" value="Login" />
<a href="register.php">Register</a>
</form>