Python/Django:如何在无效登录时显示错误消息？

Question

我正在尝试登录我的Django(2.0)网站,到目前为止我已经登录了现有帐户.我正在使用内置登录功能.

现在,我想在您输入无效帐户时显示错误消息,例如"无效的用户名或密码!".但我不知道该如何解决这个问题.

现在它只是在您输入无效帐户时刷新登录页面.任何帮助表示赞赏!

的login.html

{% block title %}Login{% endblock %}

{% block content %}
  <h2>Login</h2>
  <form method="post">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">Login</button>
  </form>
{% endblock %}

登录视图

def login(request):
    if request.method == 'POST':
        form = AuthenticationForm(request.POST)
        username = request.POST['username']
        password = request.POST['password']
        user = authenticate(username=username, password=password)

        if user is not None:
            if user.is_active:
                auth_login(request, user)
                return redirect('index')

    else:
        form = AuthenticationForm()
    return render(request, 'todo/login.html', {'form': form})

Answer 1

在您的模板中

   {% for message in messages %}

                    <div class="alert alert-success">
                        <a class="close" href="#" data-dismiss="alert">×</a>

                        {{ message }}

                    </div>
            {% endfor %}

鉴于

from django.contrib import messages

def login(request):
    if request.method == 'POST':
        form = AuthenticationForm(request.POST)
        username = request.POST['username']
        password = request.POST['password']
        user = authenticate(username=username, password=password)

        if user is not None:
            if user.is_active:
                auth_login(request, user)
                return redirect('index')
        else:
            messages.error(request,'username or password not correct')
            return redirect('login')

    else:
        form = AuthenticationForm()
    return render(request, 'todo/login.html', {'form': form})

Answer 2

您应该只在模板中添加:

{% block title %}Login{% endblock %}

{% block content %}
<h2>Login</h2>

{% if form.errors %}
    <p>username or password not correct</p>
{% endif %}

<form method="post">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">Login</button>
</form>
{% endblock %}