forms.py

# coding: utf-8
from django import forms

class Invite(forms.Form):
    email = forms.EmailField(required=True)

models.py

# coding: utf-8
from django.db import models
from django.contrib.auth.models import User


class Key(models.Model):
    user = models.ForeignKey(User)
    key = models.CharField(max_length=125)
    email = models.EmailField()
    expired = models.BooleanField(default=False)

utils.py

# coding: utf-8
from django.shortcuts import render_to_response
from django.template import RequestContext

def render(template):
    def render_with_decorator(view_func):
        def wrapper(*args, **kwargs):
            request = args[0]
            context = view_func(*args, **kwargs)

            if isinstance(context, dict):
                    return render_to_response(
                        template,
                        context,
                        context_instance = RequestContext(request),
                    )
            else:
                return context
        return wrapper
    return render_with_decorator

views.py

# coding: utf-8
from django.core.mail import EmailMessage
from uuid import uuid4
from utils import render
import forms
from models import Key

def gen_key(user):
    key = uuid4().hex
    while Key.objects.filter(user=user, key=key):
        key = uuid4().hex
    return key

@login_required
@render('users/invite.html')
def invite(request):
    if request.method == 'POST':
        form = forms.Invite(request.POST)
        invites_count = request.user.get_profile().invites
        if invites_count == 0:
            return redirect('/')

        if form.is_valid():
            email = form.cleaned_data['email']
            if User.objects.filter(email=email) or Key.objects.filter(email=email):
                return redirect('/')
            key = Key(user=request.user, key=gen_key(request.user), email=email)
            current_site = Site.objects.get_current()
            content = render_to_string('users/invite_msg.html', dict(user=request.user, key=key, site=current_site))
            key.save()

            msg = EmailMessage('Zaproszenie do serialowo.tv', content, '[email protected]', [email])
            msg.content_subtype = "html"
            msg.send()

            request.user.get_profile().invites = invites_count - 1
            request.user.get_profile().save()

            return redirect('/')

    else:
        form = forms.Invite()

    return dict(form=form)