Untitled

def user_login(request):
    if request.method == 'POST':
        username = request.POST.get('username')
        password = request.POST.get('password')

        user = authenticate(username=username, password=password)
        if user:
            if user.is_active:
                login(request, user)
                return HttpResponseRedirect('/friends_plans/users/', {'username': username, })
            else:
                return HttpResponse("Your account is disabled")
        else:
            print "Invalid login details: {0}, {1}".format(username, password)
            return HttpResponse("Invalid login details supplied.")
    else:
        return render(request, 'friends_plans/index.html', {})

{% load staticfiles %}
<html >
<head >
    <title> Friends' Plans </title>
    <meta charset ="utf -8" />
    <link rel="stylesheet" href="{% static 'css/friends_plans.css' %}">
</head >
<body >
    <div id ="container">
        <div id ="header">
            <ul id ="menu">
                <span><a id="firstbutton" href ="" >Friends' Plans</a> </span>
                <span><a id="helpbutton" href ="" >HELP</a></span>
            </ul>
        </div>
        <div id ="left">
            <form id="login_form" method="post" action="">
                {% csrf_token %}

                Username: <input type ="text" name ="username" value="" size="50" /> <br />
                Password: <input type ="password" name ="password" value="" size="50"/> <br />
                <input type ="submit" value="submit" />
            </form>
            {% if user.is_authenticated %}
            <a href="/friends_plans/logout/">Logout</a>
            {% else %}
            <a href="/friends_plans/register/">Register here</a><br />
            {% endif %}
        </div>
        <div id ="right">
            <h1 id="welcome">Welcome to Friends' Plans</h1>
            <img class="cat" src={% static 'images/cat4.jpg' %} />
            <img class="cat" src={% static 'images/cat2.jpg' %} />
            <img class="cat" src={% static 'images/cat3.jpg' %} />
            <img class="cat" src={% static 'images/cat6.jpg' %} />
            <img class="cat" src={% static 'images/cat5.jpg' %} />
            <img class="cat" src={% static 'images/cat1.jpg' %} />
        </div>
        <div id ="footer"> Copyright </div>
    </div>
</body>
</html>

from django import forms

class LoginForm(forms.Form):
    username = forms.CharField(label=u'Имя пользователя')
    password = forms.CharField(label=u'Пароль')
    next = forms.CharField(widget=forms.HiddenInput(), required=False)

from .forms import LoginForm

def user_login(request):
    if request.method == 'POST':
        form = LoginForm(request.POST)
        if form.is_valid():
            username = form.cleaned_data['username']
            password = form.cleaned_data['password']

            user = authenticate(username=username, password=password)
            if user and user.is_active:
                login(request, user)
                return HttpResponseRedirect('/friends_plans/users/', {'username': username, })
            else:
                form.add_error(None, 'Unknown or disabled account')
                return render(request, 'friends_plans/index.html', {'form': form})
        else:
            return render(request, 'friends_plans/index.html', {'form': form})
    else:
        return render(request, 'friends_plans/index.html', {'form': LoginForm()})

...
{% for error in form.non_field_errors %}
    <span class="error-message">{{ error }}</span>
{% endfor %}
<form id="login_form" method="post" action="">
    {% csrf_token %}
    {% form.as_p %}
</form>
...

from django.contrib import messages

def user_login(request):
    if request.method == 'POST':
        username = request.POST.get('username')
        password = request.POST.get('password')

        user = authenticate(username=username, password=password)
        if user:
            if user.is_active:
                login(request, user)
                return HttpResponseRedirect('/friends_plans/users/', {'username': username, })
            else:
                messages.error(request, 'Your account is disabled')
                return render(request, 'friends_plans/index.html', {})
        else:
            print "Invalid login details: {0}, {1}".format(username, password)
            messages.error(request, 'Invalid login details supplied.')
            return render(request, 'friends_plans/index.html', {})
    else:
        return render(request, 'friends_plans/index.html', {})

...
{% for message in messages %}
<div class="message {{ message.tags }}">
    {{ message }}
</div>
{% endfor %}
<form id="login_form" method="post" action="">
...