def user_login(request):
context = {}
if request.method == "POST":
    username = request.POST['username']
    password = request.POST["password"]
    user = authenticate(request,username=username,password=password)
    if user.is_authenticated:
        print("1")
        login(request, user)
        if request.GET.get('next',None):
            print("2")
            return HttpResponseRedirect(request.GET['next'])
        return HttpResponseRedirect(reverse('success'))
    else:
        print("3")
        context["error"] = "nieprawidlowe dane"
        return render(request,'auth/login.html',context)
else:
    print("4")
    return render(request,'auth/login.html',context)


 @login_required(login_url="/login/")
def success(request):
    c = {}
    c['user'] = request.user
    return render(request,'auth/success.html',c)

{% extends 'main.html' %}
{% block article %}
<p>User <b>{{ user.username }}</b> jestes zalogowony</p>
<form method="post" action="/logout/">
        {% csrf_token %}
        <input type="submit" value="Logout">
</form>
{% endblock %}