views.py

        return HttpResponse(json.dumps({'success': False,
                                        'error': 'Valid e-mail address required.'}))

    if len(User.objects.filter(email=new_email)) != 0:
        ## CRITICAL TODO: Handle case sensitivity for e-mails
        return HttpResponse(json.dumps({'success': False,
                                        'error': 'An account with this e-mail already exists.'}))

    pec_list = PendingEmailChange.objects.filter(user=request.user)
    if len(pec_list) == 0:
        pec = PendingEmailChange()
        pec.user = user
    else:
        pec = pec_list[0]

    pec.new_email = request.POST['new_email']
    pec.activation_key = uuid.uuid4().hex
    pec.save()

    if pec.new_email == user.email:
        pec.delete()
        return HttpResponse(json.dumps({'success': False,
                                        'error': 'Old email is the same as the new email.'}))

    d = {'key': pec.activation_key,
         'old_email': user.email,
         'new_email': pec.new_email}

    subject = render_to_string('emails/email_change_subject.txt', d)
    subject = ''.join(subject.splitlines())
    message = render_to_string('emails/email_change.txt', d)

    res = send_mail(subject, message, settings.DEFAULT_FROM_EMAIL, [pec.new_email])

    return HttpResponse(json.dumps({'success': True}))


@ensure_csrf_cookie
def confirm_email_change(request, key):
    ''' User requested a new e-mail. This is called when the activation
    link is clicked. We confirm with the old e-mail, and update
    '''
    try:
        pec = PendingEmailChange.objects.get(activation_key=key)
    except PendingEmailChange.DoesNotExist:
        return render_to_response("invalid_email_key.html", {})

    user = pec.user
    d = {'old_email': user.email,
         'new_email': pec.new_email}

    if len(User.objects.filter(email=pec.new_email)) != 0:
        return render_to_response("email_exists.html", d)

    subject = render_to_string('emails/email_change_subject.txt', d)
    subject = ''.join(subject.splitlines())
    message = render_to_string('emails/confirm_email_change.txt', d)
    up = UserProfile.objects.get(user=user)
    meta = up.get_meta()
    if 'old_emails' not in meta:
        meta['old_emails'] = []
    meta['old_emails'].append([user.email, datetime.datetime.now().isoformat()])
    up.set_meta(meta)
    up.save()
    # Send it to the old email...
    user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
    user.email = pec.new_email
    user.save()
    pec.delete()
    # And send it to the new email...
    user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)

    return render_to_response("email_change_successful.html", d)


@ensure_csrf_cookie
def change_name_request(request):
    ''' Log a request for a new name. '''
    if not request.user.is_authenticated:
        raise Http404

    try:
        pnc = PendingNameChange.objects.get(user=request.user)
    except PendingNameChange.DoesNotExist:
        pnc = PendingNameChange()
    pnc.user = request.user
    pnc.new_name = request.POST['new_name']
    pnc.rationale = request.POST['rationale']
    if len(pnc.new_name) < 2:
        return HttpResponse(json.dumps({'success': False, 'error': 'Name required'}))
    pnc.save()

    # The following automatically accepts name change requests. Remove this to
    # go back to the old system where it gets queued up for admin approval.
    accept_name_change_by_id(pnc.id)

    return HttpResponse(json.dumps({'success': True}))


@ensure_csrf_cookie
def pending_name_changes(request):
    ''' Web page which allows staff to approve or reject name changes. '''
    if not request.user.is_staff:
        raise Http404

    changes = list(PendingNameChange.objects.all())
    js = {'students': [{'new_name': c.new_name,
                        'rationale': c.rationale,
                        'old_name': UserProfile.objects.get(user=c.user).name,
                        'email': c.user.email,
                        'uid': c.user.id,
                        'cid': c.id} for c in changes]}
    return render_to_response('name_changes.html', js)


@ensure_csrf_cookie
def reject_name_change(request):
    ''' JSON: Name change process. Course staff clicks 'reject' on a given name change '''
    if not request.user.is_staff:
        raise Http404

    try:
        pnc = PendingNameChange.objects.get(id=int(request.POST['id']))
    except PendingNameChange.DoesNotExist:
        return HttpResponse(json.dumps({'success': False, 'error': 'Invalid ID'}))

    pnc.delete()
    return HttpResponse(json.dumps({'success': True}))


def accept_name_change_by_id(id):
    try:
        pnc = PendingNameChange.objects.get(id=id)
    except PendingNameChange.DoesNotExist:
        return HttpResponse(json.dumps({'success': False, 'error': 'Invalid ID'}))

    u = pnc.user
    up = UserProfile.objects.get(user=u)

    # Save old name
    meta = up.get_meta()
    if 'old_names' not in meta:
        meta['old_names'] = []
    meta['old_names'].append([up.name, pnc.rationale, datetime.datetime.now().isoformat()])
    up.set_meta(meta)

    up.name = pnc.new_name
    up.save()
    pnc.delete()

    return HttpResponse(json.dumps({'success': True}))


@ensure_csrf_cookie
def accept_name_change(request):
    ''' JSON: Name change process. Course staff clicks 'accept' on a given name change

    We used this during the prototype but now we simply record name changes instead
    of manually approving them. Still keeping this around in case we want to go
    back to this approval method.
    '''
    if not request.user.is_staff:
        raise Http404

    return accept_name_change_by_id(int(request.POST['id']))


def _get_news(top=None):
    "Return the n top news items on settings.RSS_URL"

    feed_data = cache.get("students_index_rss_feed_data")
    if feed_data is None:
        if hasattr(settings, 'RSS_URL'):
            feed_data = urllib.urlopen(settings.RSS_URL).read()
        else:
            feed_data = render_to_string("feed.rss", None)
        cache.set("students_index_rss_feed_data", feed_data, settings.RSS_TIMEOUT)

    feed = feedparser.parse(feed_data)
    entries = feed['entries'][0:top]  # all entries if top is None
    for entry in entries:
        soup = BeautifulSoup(entry.description)
        entry.image = soup.img['src'] if soup.img else None
        entry.summary = soup.getText()

    return entries