views.py

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import logging
import socket

from smtplib import SMTPException
from urllib import quote
from functools import wraps

from django.core.mail import send_mail
from django.http import HttpResponse, HttpResponseBadRequest
from django.shortcuts import redirect
from django.template.loader import render_to_string
from django.utils.translation import ugettext as _
from django.core.urlresolvers import reverse
from django.contrib.auth.decorators import login_required
from django.contrib import messages
from django.db import transaction
from django.contrib.auth import logout as auth_logout
from django.utils.http import urlencode
from django.http import HttpResponseRedirect, HttpResponseBadRequest
from django.db.utils import IntegrityError
from django.contrib.auth.views import password_change
from django.core.exceptions import ValidationError

from astakos.im.models import AstakosUser, Invitation, ApprovalTerms
from astakos.im.activation_backends import get_backend, SimpleBackend
from astakos.im.util import get_context, prepare_response, set_cookie, get_query
from astakos.im.forms import *
from astakos.im.functions import send_greeting, send_feedback, SendMailError
from astakos.im.settings import DEFAULT_CONTACT_EMAIL, DEFAULT_FROM_EMAIL, COOKIE_NAME, COOKIE_DOMAIN, IM_MODULES, SITENAME, LOGOUT_NEXT
from astakos.im.functions import invite as invite_func

logger = logging.getLogger(__name__)

def render_response(template, tab=None, status=200, reset_cookie=False, context_instance=None, **kwargs):
    """
    Calls ``django.template.loader.render_to_string`` with an additional ``tab``
    keyword argument and returns an ``django.http.HttpResponse`` with the
    specified ``status``.
    """
    if tab is None:
        tab = template.partition('_')[0].partition('.html')[0]
    kwargs.setdefault('tab', tab)
    html = render_to_string(template, kwargs, context_instance=context_instance)
    response = HttpResponse(html, status=status)
    if reset_cookie:
        set_cookie(response, context_instance['request'].user)
    return response


def requires_anonymous(func):
    """
    Decorator checkes whether the request.user is not Anonymous and in that case
    redirects to `logout`.
    """
    @wraps(func)
    def wrapper(request, *args):
        if not request.user.is_anonymous():
            next = urlencode({'next': request.build_absolute_uri()})
            logout_uri = reverse(logout) + '?' + next
            return HttpResponseRedirect(logout_uri)
        return func(request, *args)
    return wrapper

def signed_terms_required(func):
    """
    Decorator checkes whether the request.user is Anonymous and in that case
    redirects to `logout`.
    """
    @wraps(func)
    def wrapper(request, *args, **kwargs):
        if request.user.is_authenticated() and not request.user.signed_terms():
            params = urlencode({'next': request.build_absolute_uri(),
                              'show_form':''})
            terms_uri = reverse('latest_terms') + '?' + params
            return HttpResponseRedirect(terms_uri)
        return func(request, *args, **kwargs)
    return wrapper

@signed_terms_required
def index(request, login_template_name='im/login.html', profile_template_name='im/profile.html', extra_context={}):
    """
    If there is logged on user renders the profile page otherwise renders login page.

    **Arguments**

    ``login_template_name``
        A custom login template to use. This is optional; if not specified,
        this will default to ``im/login.html``.

    ``profile_template_name``
        A custom profile template to use. This is optional; if not specified,
        this will default to ``im/profile.html``.

    ``extra_context``
        An dictionary of variables to add to the template context.

    **Template:**

    im/profile.html or im/login.html or ``template_name`` keyword argument.

    """
    template_name = login_template_name
    if request.user.is_authenticated():
        return HttpResponseRedirect(reverse('astakos.im.views.edit_profile'))
    return render_response(template_name,
                           login_form = LoginForm(request=request),
                           context_instance = get_context(request, extra_context))

@login_required
@signed_terms_required
@transaction.commit_manually
def invite(request, template_name='im/invitations.html', extra_context={}):
    """
    Allows a user to invite somebody else.

    In case of GET request renders a form for providing the invitee information.
    In case of POST checks whether the user has not run out of invitations and then
    sends an invitation email to singup to the service.

    The view uses commit_manually decorator in order to ensure the number of the
    user invitations is going to be updated only if the email has been successfully sent.

    If the user isn't logged in, redirects to settings.LOGIN_URL.

    **Arguments**

    ``template_name``
        A custom template to use. This is optional; if not specified,
        this will default to ``im/invitations.html``.

    ``extra_context``
        An dictionary of variables to add to the template context.

    **Template:**

    im/invitations.html or ``template_name`` keyword argument.

    **Settings:**

    The view expectes the following settings are defined:

    * LOGIN_URL: login uri
    * ASTAKOS_DEFAULT_CONTACT_EMAIL: service support email
    * ASTAKOS_DEFAULT_FROM_EMAIL: from email
    """
    status = None
    message = None
    form = InvitationForm()
    
    inviter = request.user
    if request.method == 'POST':
        form = InvitationForm(request.POST)
        if inviter.invitations > 0:
            if form.is_valid():
                try:
                    invitation = form.save()
                    invite_func(invitation, inviter)
                    status = messages.SUCCESS
                    message = _('Invitation sent to %s' % invitation.username)
                except SendMailError, e:
                    status = messages.ERROR
                    message = e.message
                    transaction.rollback()
                except BaseException, e:
                    status = messages.ERROR
                    message = _('Something went wrong.')
                    logger.exception(e)
                    transaction.rollback()
                else:
                    transaction.commit()
        else:
            status = messages.ERROR
            message = _('No invitations left')
    messages.add_message(request, status, message)

    sent = [{'email': inv.username,
             'realname': inv.realname,
             'is_consumed': inv.is_consumed}
             for inv in request.user.invitations_sent.all()]
    kwargs = {'inviter': inviter,
              'sent':sent}
    context = get_context(request, extra_context, **kwargs)
    return render_response(template_name,
                           invitation_form = form,
                           context_instance = context)

@login_required
@signed_terms_required
def edit_profile(request, template_name='im/profile.html', extra_context={}):
    """
    Allows a user to edit his/her profile.

    In case of GET request renders a form for displaying the user information.
    In case of POST updates the user informantion and redirects to ``next``
    url parameter if exists.

    If the user isn't logged in, redirects to settings.LOGIN_URL.

    **Arguments**

    ``template_name``
        A custom template to use. This is optional; if not specified,
        this will default to ``im/profile.html``.

    ``extra_context``
        An dictionary of variables to add to the template context.

    **Template:**

    im/profile.html or ``template_name`` keyword argument.

    **Settings:**

    The view expectes the following settings are defined:

    * LOGIN_URL: login uri
    """
    form = ProfileForm(instance=request.user)
    extra_context['next'] = request.GET.get('next')
    reset_cookie = False
    if request.method == 'POST':
        form = ProfileForm(request.POST, instance=request.user)
        if form.is_valid():
            try:
                prev_token = request.user.auth_token
                user = form.save()
                reset_cookie = user.auth_token != prev_token
                form = ProfileForm(instance=user)
                next = request.POST.get('next')
                if next:
                    return redirect(next)
                msg = _('Profile has been updated successfully')
                messages.add_message(request, messages.SUCCESS, msg)
            except ValueError, ve:
                messages.add_message(request, messages.ERROR, ve)
    return render_response(template_name,
                           reset_cookie = reset_cookie,
                           profile_form = form,
                           context_instance = get_context(request,
                                                          extra_context))

def signup(request, template_name='im/signup.html', on_success='im/signup_complete.html', extra_context={}, backend=None):
    """
    Allows a user to create a local account.

    In case of GET request renders a form for providing the user information.
    In case of POST handles the signup.

    The user activation will be delegated to the backend specified by the ``backend`` keyword argument
    if present, otherwise to the ``astakos.im.activation_backends.InvitationBackend``
    if settings.ASTAKOS_INVITATIONS_ENABLED is True or ``astakos.im.activation_backends.SimpleBackend`` if not
    (see activation_backends);
    
    Upon successful user creation if ``next`` url parameter is present the user is redirected there
    otherwise renders the same page with a success message.
    
    On unsuccessful creation, renders ``template_name`` with an error message.
    
    **Arguments**
    
    ``template_name``
        A custom template to render. This is optional;
        if not specified, this will default to ``im/signup.html``.


    ``on_success``
        A custom template to render in case of success. This is optional;
        if not specified, this will default to ``im/signup_complete.html``.

    ``extra_context``
        An dictionary of variables to add to the template context.

    **Template:**
    
    im/signup.html or ``template_name`` keyword argument.
    im/signup_complete.html or ``on_success`` keyword argument. 
    """
    if request.user.is_authenticated():
        return HttpResponseRedirect(reverse('astakos.im.views.index'))
    
    provider = get_query(request).get('provider', 'local')
    try:
        if not backend:
            backend = get_backend(request)
        form = backend.get_signup_form(provider)
    except Exception, e:
        form = SimpleBackend(request).get_signup_form(provider)
        messages.add_message(request, messages.ERROR, e)
    if request.method == 'POST':
        if form.is_valid():
            user = form.save(commit=False)
            try:
                result = backend.handle_activation(user)
                status = messages.SUCCESS
                message = result.message
                user.save()
                if user and user.is_active:
                    next = request.POST.get('next', '')
                    return prepare_response(request, user, next=next)
                messages.add_message(request, status, message)
                return render_response(on_success,
                                       context_instance=get_context(request, extra_context))
            except SendMailError, e:
                status = messages.ERROR
                message = e.message
                messages.add_message(request, status, message)
            except BaseException, e:
                status = messages.ERROR
                message = _('Something went wrong.')
                messages.add_message(request, status, message)
                logger.exception(e)
    return render_response(template_name,
                           signup_form = form,
                           provider = provider,
                           context_instance=get_context(request, extra_context))

@login_required
@signed_terms_required
def feedback(request, template_name='im/feedback.html', email_template_name='im/feedback_mail.txt', extra_context={}):
    """
    Allows a user to send feedback.

    In case of GET request renders a form for providing the feedback information.
    In case of POST sends an email to support team.

    If the user isn't logged in, redirects to settings.LOGIN_URL.

    **Arguments**

    ``template_name``
        A custom template to use. This is optional; if not specified,
        this will default to ``im/feedback.html``.

    ``extra_context``
        An dictionary of variables to add to the template context.

    **Template:**

    im/signup.html or ``template_name`` keyword argument.

    **Settings:**

    * LOGIN_URL: login uri
    * ASTAKOS_DEFAULT_CONTACT_EMAIL: List of feedback recipients
    """
    if request.method == 'GET':
        form = FeedbackForm()
    if request.method == 'POST':
        if not request.user:
            return HttpResponse('Unauthorized', status=401)

        form = FeedbackForm(request.POST)
        if form.is_valid():
            msg = form.cleaned_data['feedback_msg'],
            data = form.cleaned_data['feedback_data']
            try:
                send_feedback(msg, data, request.user, email_template_name)
            except SendMailError, e:
                message = e.message
                status = messages.ERROR
            else:
                message = _('Feedback successfully sent')
                status = messages.SUCCESS
            messages.add_message(request, status, message)
    return render_response(template_name,
                           feedback_form = form,
                           context_instance = get_context(request, extra_context))

def logout(request, template='registration/logged_out.html', extra_context={}):
    """
    Wraps `django.contrib.auth.logout` and delete the cookie.
    """
    auth_logout(request)
    response = HttpResponse()
    response.delete_cookie(COOKIE_NAME, path='/', domain=COOKIE_DOMAIN)
    next = request.GET.get('next')
    if next:
        response['Location'] = next
        response.status_code = 302
        return response
    elif LOGOUT_NEXT:
        response['Location'] = LOGOUT_NEXT
        response.status_code = 301
        return response
    messages.add_message(request, messages.SUCCESS, _('You have successfully logged out.'))
    context = get_context(request, extra_context)
    response.write(render_to_string(template, context_instance=context))
    return response

@transaction.commit_manually
def activate(request, email_template_name='im/welcome_email.txt', on_failure='im/signup.html'):
    """
    Activates the user identified by the ``auth`` request parameter, sends a welcome email
    and renews the user token.

    The view uses commit_manually decorator in order to ensure the user state will be updated
    only if the email will be send successfully.
    """
    token = request.GET.get('auth')
    next = request.GET.get('next')
    try:
        user = AstakosUser.objects.get(auth_token=token)
    except AstakosUser.DoesNotExist:
        return HttpResponseBadRequest(_('No such user'))
    
    try:
        local_user = AstakosUser.objects.get(email=user.email, is_active=True)
    except AstakosUser.DoesNotExist:
        user.is_active = True
        user.email_verified = True
        try:
            user.save()
        except ValidationError, e:
            return HttpResponseBadRequest(e)
    else:
        # switch the existing account to shibboleth one
        local_user.provider = 'shibboleth'
        local_user.set_unusable_password()
        local_user.third_party_identifier = user.third_party_identifier
        try:
            local_user.save()
        except ValidationError, e:
            return HttpResponseBadRequest(e)
        user.delete()
        user = local_user
    
    try:
        send_greeting(user, email_template_name)
        response = prepare_response(request, user, next, renew=True)
        transaction.commit()
        return response
    except SendMailError, e:
        message = e.message
        messages.add_message(request, messages.ERROR, message)
        transaction.rollback()
        return render_response(on_failure)
    except BaseException, e:
        status = messages.ERROR
        message = _('Something went wrong.')
        messages.add_message(request, messages.ERROR, message)
        logger.exception(e)
        transaction.rollback()
        return signup(request, on_failure)

def approval_terms(request, term_id=None, template_name='im/approval_terms.html', extra_context={}):
    term = None
    terms = None
    if not term_id:
        try:
            term = ApprovalTerms.objects.order_by('-id')[0]
        except IndexError:
            pass
    else:
        try:
             term = ApprovalTerms.objects.get(id=term_id)
        except ApprovalTermDoesNotExist, e:
            pass

    if not term:
        return HttpResponseRedirect(reverse('astakos.im.views.index'))
    f = open(term.location, 'r')
    terms = f.read()

    if request.method == 'POST':
        next = request.POST.get('next')
        if not next:
            next = reverse('astakos.im.views.index')
        form = SignApprovalTermsForm(request.POST, instance=request.user)
        if not form.is_valid():
            return render_response(template_name,
                           terms = terms,
                           approval_terms_form = form,
                           context_instance = get_context(request, extra_context))
        user = form.save()
        return HttpResponseRedirect(next)
    else:
        form = None
        if request.user.is_authenticated() and not request.user.signed_terms():
            form = SignApprovalTermsForm(instance=request.user)
        return render_response(template_name,
                               terms = terms,
                               approval_terms_form = form,
                               context_instance = get_context(request, extra_context))

@signed_terms_required
def change_password(request):
    return password_change(request, post_change_redirect=reverse('astakos.im.views.edit_profile'))

@transaction.commit_manually
def change_email(request, activation_key=None,
                 email_template_name='registration/email_change_email.txt',
                 form_template_name='registration/email_change_form.html',
                 confirm_template_name='registration/email_change_done.html',
                 extra_context={}):
    if activation_key:
        try:
            user = EmailChange.objects.change_email(activation_key)
            if request.user.is_authenticated() and request.user == user:
                msg = _('Email changed successfully.')
                messages.add_message(request, messages.SUCCESS, msg)
                auth_logout(request)
                response = prepare_response(request, user)
                transaction.commit()
                return response
        except ValueError, e:
            messages.add_message(request, messages.ERROR, e)
        return render_response(confirm_template_name,
                               modified_user = user if 'user' in locals() else None,
                               context_instance = get_context(request,
                                                              extra_context))
    
    if not request.user.is_authenticated():
        path = quote(request.get_full_path())
        url = request.build_absolute_uri(reverse('astakos.im.views.index'))
        return HttpResponseRedirect(url + '?next=' + path)
    form = EmailChangeForm(request.POST or None)
    if request.method == 'POST' and form.is_valid():
        try:
            ec = form.save(email_template_name, request)
        except SendMailError, e:
            status = messages.ERROR
            msg = e
            transaction.rollback()
        except IntegrityError, e:
            status = messages.ERROR
            msg = _('There is already a pending change email request.')
        else:
            status = messages.SUCCESS
            msg = _('Change email request has been registered succefully.\
                    You are going to receive a verification email in the new address.')
            transaction.commit()
        messages.add_message(request, status, msg)
    return render_response(form_template_name,
                           form = form,
                           context_instance = get_context(request,
                                                          extra_context))