PHP-AJAX登录无法正常工作

Question

I'm currently working on a AJAX login system, but it doesn't send any response back. It only sends a response back when I exit("error here") the script, but I want to return a JSON response.

My form:

<div id="account" class="modal" role="dialog">
    <div class="modal-dialog">
        <form method="post" id="login-form">
            <div class="modal-content">
                <div class="modal-header">
                    <h4 class="modal-title">Sign in</h4>
                </div>
                <div class="modal-body">
                        <p>
                            Email address:<br />
                            <input type="email" class="form-control" placeholder="Email address" name="user_email" id="user_email" />
                        </p>
                        <p>
                            Password:<br />
                            <input type="password" class="form-control" placeholder="Password" name="password" id="password" />
                        </p>
                    </form>
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
                    <button type="submit" class="btn btn-default" name="btn-login" id="btn-login">LOGIN</button>
                </div>
            </div>
        </form>
    </div>
</div>

My JavaScript:

    $("#btn-login").click(function(e) {
        alert('submit');
        var data = $("#login-form").serialize();
        alert(data);
        $.ajax({
            url: 'ajax.php',
            type: 'POST',
            data: data,
            success: function(response) {
                var data = response.responseText;
                var resp = $.parseJSON(data);

                if (resp.error) {
                    alert('error: ' + response);
                } else {
                    alert('success: ' + response);
                }
            }
        });
        event.preventDefault();
    });

My PHP:

if(isset($_POST['user_email']) && is_ajax()) {
    $engine->expireLoginAttempts();
    $engine->expireLoginBan();

    if(!$engine->isLoginBanned()) {
        $email = strip_tags($_POST['user_email']);
        $password = strip_tags($_POST['password']);

        if($engine->doLogin($email,$password)) {
            $engine->expireBan();

            if($maintenanc['value'] == '1' && !$engine->isStaff()) {
                echo json_encode(array(
                    'success' => '0',
                    'message' => 'You can\'t login using a regular account because the site is currently under maintenance.'
                ));
            } elseif($engine->isBanned() && !$engine->isOwner()) {
                // Account banned; notify and give a timestamp + reason
                $stmt = $engine->runQuery("SELECT timestamp, expiration, reason FROM banned WHERE user_id=:user_id");
                $stmt->execute(array(':user_id'=>$_SESSION['user_id']));
                $userRow = $stmt->fetch(PDO::FETCH_ASSOC);
                $blockdate1 = strtotime('+' . $userRow['expiration'], strtotime($userRow['timestamp']));
                $blockdate2 = date('d-m-Y H:i:s', $blockdate1);

                echo json_encode(array(
                    'success' => '0',
                    'message' => 'This account is suspended until ' . $blockdate2 . ' because of the following reason: ' . $userRow['reason'] . '.'
                ));
            } else {
                echo json_encode(array(
                    'success' => '1',
                    'message' => $_SESSION['user_name'];
                ));
            }
        } else {
            // Create login attempt if the account exists and the ip is different from the register ip
            $stmt = $engine->runQuery("SELECT user_email, user_id, user_ip FROM users WHERE user_email=:email");
            $stmt->execute(array(':email'=>$email));
            $userRow = $stmt->fetch(PDO::FETCH_ASSOC);
            if($stmt->rowCount() == 1 && $userRow['user_ip'] !== $_SERVER["REMOTE_ADDR"]) {
                $engine->createLoginAttempt($userRow['user_id'], $_SERVER["REMOTE_ADDR"]);
            }

            // Bruteforce attack suspected, bans the ip after 10 attempts from an unknown ip
            $attemptban = $engine->runQuery("SELECT * FROM loginattempt WHERE ip=:ip");
            $attemptban->execute(array(':ip'=>$_SERVER["REMOTE_ADDR"]));
            if($attemptban->rowCount() > 4) {
                if($engine->loginban()) {
                    $engine->deleteLoginAttempts($_SERVER["REMOTE_ADDR"]);
                }
            }

            echo json_encode(array(
                'success' => '0',
                'message' => 'Emailaddress and/or password invalid.'
            ));
        }   
    }
}

Does anybody know what I'm doing wrong? I've tried exiting the json_encode, putting exit() after each json_encode but none seem to work.. Any help is greatly appreciated!

Answer 1

Try add something to the else and see what's happened.

if(!$engine->isLoginBanned()){
    ...
} else {
    // Try add something here and see what's happen, eg.
    echo json_encode(array(
        'success' => '0',
        'message' => 'Sorry, isLoginBanned';
    ));
}

</div>