zulip/zephyr/views.py

from django.conf import settings
from django.contrib.auth import authenticate, login
from django.contrib.auth.decorators import login_required
from django.core.urlresolvers import reverse
from django.http import HttpResponseRedirect
from django.shortcuts import render_to_response, redirect
from django.template import RequestContext, loader
from django.utils.timezone import now
from django.core.exceptions import ValidationError
from django.core import validators
from django.contrib.auth.views import login as django_login_page, \
    logout_then_login as django_logout_then_login
from django.db.models import Q, F
from django.core.mail import send_mail, mail_admins
from zephyr.models import Message, UserProfile, Stream, Subscription, \
    Recipient, get_huddle, Realm, UserMessage, \
    PreregistrationUser, get_client, MitUser, User, UserActivity, \
    MAX_SUBJECT_LENGTH, MAX_MESSAGE_LENGTH, get_stream, UserPresence, \
    get_recipient, valid_stream_name
from zephyr.lib.actions import do_add_subscription, do_remove_subscription, \
    do_change_password, create_mit_user_if_needed, do_change_full_name, \
    do_change_enable_desktop_notifications, do_change_enter_sends, \
    do_activate_user, add_default_subs, do_create_user, check_send_message, \
    log_subscription_property_change, internal_send_message, \
    create_stream_if_needed, gather_subscriptions, subscribed_to_stream, \
    update_user_presence, set_stream_color, get_stream_colors, update_message_flags, \
    recipient_for_emails, extract_recipients
from zephyr.forms import RegistrationForm, HomepageForm, ToSForm, is_unique, \
    is_inactive, isnt_mit
from django.views.decorators.csrf import csrf_exempt

from zephyr.decorator import require_post, \
    authenticated_api_view, authenticated_json_post_view, \
    has_request_variables, POST, authenticated_json_view, \
    to_non_negative_int, json_to_dict, json_to_list, json_to_bool, \
    JsonableError, RequestVariableMissingError, get_user_profile_by_email, \
    get_user_profile_by_user_id
from zephyr.lib.query import last_n
from zephyr.lib.avatar import gravatar_hash
from zephyr.lib.response import json_success, json_error, json_response
from zephyr.lib.timestamp import timestamp_to_datetime, datetime_to_timestamp
from zephyr.lib.cache import cache_with_key

from zephyr import tornado_callbacks

from confirmation.models import Confirmation

import datetime
import simplejson
import re
import urllib
import time
import requests
import os
import base64
from collections import defaultdict
from zephyr.lib import bugdown

def list_to_streams(streams_raw, user_profile, autocreate=False, invite_only=False):
    """Converts plaintext stream names to a list of Streams, validating input in the process

    For each stream name, we validate it to ensure it meets our requirements for a proper
    stream name: that is, that it is shorter than 30 characters and passes valid_stream_name.

    We also ensure the stream is visible to the user_profile who made the request; a call
    to list_to_streams will fail if one of the streams is invite_only and user_profile
    is not already on the stream.

    This function in autocreate mode should be atomic: either an exception will be raised
    during a precheck, or all the streams specified will have been created if applicable.

    @param streams_raw The list of stream names to process
    @param user_profile The user for whom we are retreiving the streams
    @param autocreate Whether we should create streams if they don't already exist
    @param invite_only Whether newly created streams should have the invite_only bit set
    """
    streams = []
    # Validate all streams, getting extant ones, then get-or-creating the rest.
    stream_set = set(stream_name.strip() for stream_name in streams_raw)
    rejects = []
    for stream_name in stream_set:
        if len(stream_name) > Stream.MAX_NAME_LENGTH:
            raise JsonableError("Stream name (%s) too long." % (stream_name,))
        if not valid_stream_name(stream_name):
            raise JsonableError("Invalid stream name (%s)." % (stream_name,))
        stream = get_stream(stream_name, user_profile.realm)

        if stream is None:
            rejects.append(stream_name)
        else:
            streams.append(stream)
            # Verify we can access the stream
            if stream.invite_only and not subscribed_to_stream(user_profile, stream):
                raise JsonableError("Unable to access invite-only stream (%s)." % stream.name)
    if autocreate:
        for stream_name in rejects:
            stream, created = create_stream_if_needed(user_profile.realm,
                                                 stream_name,
                                                 invite_only=invite_only)
            streams.append(stream)
    elif rejects:
        raise JsonableError("Stream(s) (%s) do not exist" % ", ".join(rejects))

    return streams

def send_signup_message(sender, signups_stream, user_profile, internal=False):
    if internal:
        # When this is done using manage.py vs. the web interface
        internal_blurb = " **INTERNAL SIGNUP** "
    else:
        internal_blurb = " "

    internal_send_message(sender,
            "stream", signups_stream, user_profile.realm.domain,
            "%s <`%s`> just signed up for Humbug!%s(total: **%i**)" % (
                user_profile.full_name,
                user_profile.user.email,
                internal_blurb,
                UserProfile.objects.filter(realm=user_profile.realm,
                                           user__is_active=True).count(),
                )
            )

def notify_new_user(user_profile, internal=False):
    send_signup_message("humbug+signups@humbughq.com", "signups", user_profile, internal)

class PrincipalError(JsonableError):
    def __init__(self, principal):
        self.principal = principal

    def to_json_error_msg(self):
        return ("User not authorized to execute queries on behalf of '%s'"
                % (self.principal,))

def principal_to_user_profile(agent, principal):
    principal_doesnt_exist = False
    try:
        principal_user_profile = get_user_profile_by_email(principal)
    except UserProfile.DoesNotExist:
        principal_doesnt_exist = True

    if (principal_doesnt_exist
        or agent.realm.domain == 'mit.edu'
        or agent.realm != principal_user_profile.realm):
        # We have to make sure we don't leak information about which users
        # are registered for Humbug in a different realm.  We could do
        # something a little more clever and check the domain part of the
        # principal to maybe give a better error message
        raise PrincipalError(principal)

    return principal_user_profile

@require_post
def accounts_register(request):
    key = request.POST['key']
    confirmation = Confirmation.objects.get(confirmation_key=key)
    prereg_user = confirmation.content_object
    email = prereg_user.email
    mit_beta_user = isinstance(confirmation.content_object, MitUser)

    # If someone invited you, you are joining their realm regardless
    # of your e-mail address.
    #
    # MitUsers can't be referred and don't have a referred_by field.
    if not mit_beta_user and prereg_user.referred_by:
        domain = prereg_user.referred_by.realm.domain
    else:
        domain = email.split('@')[-1]

    try:
        if mit_beta_user:
            # MIT users already exist, but are supposed to be inactive.
            is_inactive(email)
        else:
            # Other users should not already exist at all.
            is_unique(email)
    except ValidationError:
        return HttpResponseRedirect(reverse('django.contrib.auth.views.login') + '?email=' + urllib.quote_plus(email))

    if request.POST.get('from_confirmation'):
        form = RegistrationForm()
    else:
        form = RegistrationForm(request.POST)
        if form.is_valid():
            password   = form.cleaned_data['password']
            full_name  = form.cleaned_data['full_name']
            short_name = email.split('@')[0]
            (realm, _) = Realm.objects.get_or_create(domain=domain)

            # FIXME: sanitize email addresses and fullname
            if mit_beta_user:
                user = User.objects.get(email=email)
                do_activate_user(user)
                do_change_password(user, password)
                user_profile = user.userprofile
                do_change_full_name(user_profile, full_name)
            else:
                user_profile = do_create_user(email, password, realm, full_name, short_name)
                # We want to add the default subs list iff there were no subs
                # specified when the user was invited.
                streams = prereg_user.streams.all()
                if len(streams) == 0:
                    add_default_subs(user_profile)
                else:
                    for stream in streams:
                        do_add_subscription(user_profile, stream)
                if prereg_user.referred_by is not None:
                    # This is a cross-realm private message.
                    internal_send_message("humbug+signups@humbughq.com",
                            "private", prereg_user.referred_by.user.email, user_profile.realm.domain,
                            "%s <`%s`> accepted your invitation to join Humbug!" % (
                                user_profile.full_name,
                                user_profile.user.email,
                                )
                            )

            notify_new_user(user_profile)

            login(request, authenticate(username=email, password=password))
            return HttpResponseRedirect(reverse('zephyr.views.home'))

    return render_to_response('zephyr/register.html',
        { 'form': form, 'company_name': domain, 'email': email, 'key': key },
        context_instance=RequestContext(request))

@login_required(login_url = settings.HOME_NOT_LOGGED_IN)
def accounts_accept_terms(request):
    email = request.user.email
    company_name = email.split('@')[-1]
    if request.method == "POST":
        form = ToSForm(request.POST)
        if form.is_valid():
            full_name = form.cleaned_data['full_name']
            send_mail('Terms acceptance for ' + full_name,
                    loader.render_to_string('zephyr/tos_accept_body.txt',
                        {'name': full_name,
                         'email': email,
                         'ip': request.META['REMOTE_ADDR'],
                         'browser': request.META['HTTP_USER_AGENT']}),
                        "humbug@humbughq.com",
                        ["all@humbughq.com"])
            do_change_full_name(request.user.userprofile, full_name)
            return redirect(home)

    else:
        form = ToSForm()
    return render_to_response('zephyr/accounts_accept_terms.html',
        { 'form': form, 'company_name': company_name, 'email': email },
        context_instance=RequestContext(request))

@authenticated_json_post_view
@has_request_variables
def json_invite_users(request, user_profile, invitee_emails=POST):
    # Validation
    if settings.ALLOW_REGISTER == False:
        try:
            isnt_mit(user_profile.user.email)
        except ValidationError:
            return json_error("Invitations are not enabled for MIT at this time.")

    if not invitee_emails:
        return json_error("You must specify at least one email address.")

    invitee_emails = set(re.split(r'[, \n]', invitee_emails))

    stream_names = request.POST.getlist('stream')
    if not stream_names:
        return json_error("You must specify at least one stream for invitees to join.")

    streams = []
    for stream_name in stream_names:
        stream = get_stream(stream_name, user_profile.realm)
        if stream is None:
            return json_error("Stream does not exist: %s. No invites were sent." % stream_name)
        streams.append(stream)

    new_prereg_users = []
    errors = []
    skipped = []
    for email in invitee_emails:
        if email == '':
            continue

        if not validators.email_re.match(email):
            errors.append((email, "Invalid address."))
            continue

        if user_profile.realm.restricted_to_domain and \
                email.split('@', 1)[-1] != user_profile.realm.domain:
            errors.append((email, "Outside your domain."))
            continue

        # Redundant check in case earlier validation preventing MIT users from
        # inviting people fails.
        if settings.ALLOW_REGISTER == False:
            try:
                isnt_mit(email)
            except ValidationError:
                errors.append((email, "Invitations are not enabled for MIT at this time."))
                continue

        try:
            is_unique(email)
        except ValidationError:
            skipped.append((email, "Already has an account."))
            continue

        # The logged in user is the referrer.
        user = PreregistrationUser(email=email, referred_by=user_profile)

        # We save twice because you cannot associate a ManyToMany field
        # on an unsaved object.
        user.save()
        user.streams = streams
        user.save()

        new_prereg_users.append(user)

    if errors:
        return json_error(data={'errors': errors},
                          msg="Some emails did not validate, so we didn't send any invitations.")

    if skipped and len(skipped) == len(invitee_emails):
        # All e-mails were skipped, so we didn't actually invite anyone.
        return json_error(data={'errors': skipped},
                          msg="We weren't able to invite anyone.")

    # If we encounter an exception at any point before now, there are no unwanted side-effects,
    # since it is totally fine to have duplicate PreregistrationUsers
    for user in new_prereg_users:
        Confirmation.objects.send_confirmation(user, user.email,
                additional_context={'referrer': user_profile},
                subject_template_path='confirmation/invite_email_subject.txt',
                body_template_path='confirmation/invite_email_body.txt')

    if skipped:
        return json_error(data={'errors': skipped},
                          msg="Some of those addresses are already using Humbug, \
so we didn't send them an invitation. We did send invitations to everyone else!")
    else:
        return json_success()

def login_page(request, **kwargs):
    template_response = django_login_page(request, **kwargs)
    try:
        template_response.context_data['email'] = request.GET['email']
    except KeyError:
        pass
    return template_response

@require_post
def logout_then_login(request, **kwargs):
    return django_logout_then_login(request, kwargs)

def accounts_home(request):
    if request.method == 'POST':
        form = HomepageForm(request.POST)
        if form.is_valid():
            email = form.cleaned_data['email']
            user = PreregistrationUser()
            user.email = email
            user.save()
            Confirmation.objects.send_confirmation(user, user.email)
            return HttpResponseRedirect(reverse('send_confirm', kwargs={'email':user.email}))
        try:
            email = request.POST['email']
            # Note: We don't check for uniqueness
            is_inactive(email)
        except ValidationError:
            return HttpResponseRedirect(reverse('django.contrib.auth.views.login') + '?email=' + urllib.quote_plus(email))
    else:
        form = HomepageForm()
    return render_to_response('zephyr/accounts_home.html', {'form': form},
                              context_instance=RequestContext(request))

@login_required(login_url = settings.HOME_NOT_LOGGED_IN)
def home(request):
    # We need to modify the session object every two weeks or it will expire.
    # This line makes reloading the page a sufficient action to keep the
    # session alive.
    request.session.modified = True

    user_profile = get_user_profile_by_user_id(request.user.id)

    num_messages = UserMessage.objects.filter(user_profile=user_profile).count()

    # Brand new users get the tutorial.
    # Compute this here, before we set user_profile.pointer below.
    needs_tutorial = settings.TUTORIAL_ENABLED and user_profile.pointer == -1

    if user_profile.pointer == -1 and num_messages > 0:
        # Put the new user's pointer at the bottom
        #
        # This improves performance, because we limit backfilling of messages
        # before the pointer.  It's also likely that someone joining an
        # organization is interested in recent messages more than the very
        # first messages on the system.

        max_id = (UserMessage.objects.filter(user_profile=user_profile)
                                     .order_by('message')
                                     .reverse()[0]).message_id
        user_profile.pointer = max_id
        user_profile.last_pointer_updater = request.session.session_key

    # Populate personals autocomplete list based on everyone in your
    # realm.  Later we might want a 2-layer autocomplete, where we
    # consider specially some sort of "buddy list" who e.g. you've
    # talked to before, but for small organizations, the right list is
    # everyone in your realm.
    people = [{'email'     : profile.user.email,
               'full_name' : profile.full_name}
              for profile in
              UserProfile.objects.select_related().filter(realm=user_profile.realm)]

    # Pass parameters to the client-side JavaScript code.
    # These end up in a global JavaScript Object named 'page_params'.
    page_params = simplejson.encoder.JSONEncoderForHTML().encode(dict(
        debug_mode            = settings.DEBUG,
        poll_timeout          = settings.POLL_TIMEOUT,
        have_initial_messages = num_messages > 0,
        stream_list           = gather_subscriptions(user_profile),
        people_list           = people,
        initial_pointer       = user_profile.pointer,
        fullname              = user_profile.full_name,
        email                 = user_profile.user.email,
        domain                = user_profile.realm.domain,
        enter_sends           = user_profile.enter_sends,
        needs_tutorial        = needs_tutorial,
        desktop_notifications_enabled =
            user_profile.enable_desktop_notifications,
    ))

    try:
        isnt_mit(user_profile.user.email)
        show_invites = True
    except ValidationError:
        show_invites = settings.ALLOW_REGISTER

    return render_to_response('zephyr/index.html',
                              {'user_profile': user_profile,
                               'page_params' : page_params,
                               'email_hash'  : gravatar_hash(user_profile.user.email),
                               'show_debug':
                                   settings.DEBUG and ('show_debug' in request.GET),
                               'show_invites': show_invites
                               },
                              context_instance=RequestContext(request))

@authenticated_api_view
def api_update_pointer(request, user_profile):
    return update_pointer_backend(request, user_profile)

@authenticated_json_post_view
def json_update_pointer(request, user_profile):
    return update_pointer_backend(request, user_profile)

@has_request_variables
def update_pointer_backend(request, user_profile,
                           pointer=POST(converter=to_non_negative_int)):
    if pointer <= user_profile.pointer:
        return json_success()

    user_profile.pointer = pointer
    user_profile.save(update_fields=["pointer"])

    if request.client.name.lower() in ['android', 'iphone']:
        # TODO (leo)
        # Until we handle the new read counts in the mobile apps natively,
        # this is a shim that will mark as read any messages up until the
        # pointer move
        UserMessage.objects.filter(user_profile=user_profile,
                                   message__id__lte=pointer,
                                   flags=~UserMessage.flags.read)        \
                           .update(flags=F('flags').bitor(UserMessage.flags.read))

    if settings.TORNADO_SERVER:
        tornado_callbacks.send_notification(dict(
            type            = 'pointer_update',
            user            = user_profile.id,
            new_pointer     = pointer))

    return json_success()

@authenticated_json_post_view
def json_get_old_messages(request, user_profile):
    return get_old_messages_backend(request, user_profile=user_profile,
                                    apply_markdown=True)

@authenticated_api_view
@has_request_variables
def api_get_old_messages(request, user_profile,
                         apply_markdown=POST(default=False,
                                             converter=simplejson.loads)):
    return get_old_messages_backend(request, user_profile=user_profile,
                                    apply_markdown=apply_markdown)

class BadNarrowOperator(Exception):
    def __init__(self, desc):
        self.desc = desc

    def to_json_error_msg(self):
        return 'Invalid narrow operator: ' + self.desc

class NarrowBuilder(object):
    def __init__(self, user_profile):
        self.user_profile = user_profile

    def __call__(self, query, operator, operand):
        # We have to be careful here because we're letting users call a method
        # by name! The prefix 'by_' prevents it from colliding with builtin
        # Python __magic__ stuff.
        method_name = 'by_' + operator.replace('-', '_')
        if method_name == 'by_search':
            return self.do_search(query, operand)
        method = getattr(self, method_name, None)
        if method is None:
            raise BadNarrowOperator('unknown operator ' + operator)
        return query.filter(method(operand))

    def by_is(self, operand):
        if operand == 'private-message':
            return (Q(message__recipient__type=Recipient.PERSONAL) |
                    Q(message__recipient__type=Recipient.HUDDLE))
        raise BadNarrowOperator("unknown 'is' operand " + operand)

    def by_stream(self, operand):
        stream = get_stream(operand, self.user_profile.realm)
        if stream is None:
            raise BadNarrowOperator('unknown stream ' + operand)
        recipient = get_recipient(Recipient.STREAM, type_id=stream.id)
        return Q(message__recipient=recipient)

    def by_subject(self, operand):
        return Q(message__subject__iexact=operand)

    def by_sender(self, operand):
        return Q(message__sender__user__email__iexact=operand)

    def by_pm_with(self, operand):
        if ',' in operand:
            # Huddle
            try:
                emails = [e.strip() for e in operand.split(',')]
                recipient = recipient_for_emails(emails, False,
                    self.user_profile, self.user_profile)
            except ValidationError:
                raise BadNarrowOperator('unknown recipient ' + operand)
            return Q(message__recipient=recipient)
        else:
            # Personal message
            self_recipient = get_recipient(Recipient.PERSONAL, type_id=self.user_profile.id)
            if operand == self.user_profile.user.email:
                # Personals with self
                return Q(message__recipient__type=Recipient.PERSONAL,
                         message__sender=self.user_profile, message__recipient=self_recipient)

            # Personals with other user; include both directions.
            try:
                narrow_profile = get_user_profile_by_email(operand)
            except UserProfile.DoesNotExist:
                raise BadNarrowOperator('unknown user ' + operand)

            narrow_recipient = get_recipient(Recipient.PERSONAL, narrow_profile.id)
            return ((Q(message__sender=narrow_profile) & Q(message__recipient=self_recipient)) |
                    (Q(message__sender=self.user_profile) & Q(message__recipient=narrow_recipient)))

    def do_search(self, query, operand):
        if "postgres" in settings.DATABASES["default"]["ENGINE"]:
            sql = "search_tsvector @@ plainto_tsquery('pg_catalog.english', %s)"
            return query.extra(where=[sql], params=[operand])
        else:
            for word in operand.split():
                query = query.filter(Q(message__content__icontains=word) |
                                     Q(message__subject__icontains=word))
            return query


def narrow_parameter(json):
    # FIXME: A hack to support old mobile clients
    if json == '{}':
        return None

    data = json_to_list(json)
    for elem in data:
        if not isinstance(elem, list):
            raise ValueError("element is not a list")
        if (len(elem) != 2
            or any(not isinstance(x, str) and not isinstance(x, unicode)
                   for x in elem)):
            raise ValueError("element is not a string pair")
    return data

def get_public_stream(request, stream, realm):
    if not valid_stream_name(stream):
        raise JsonableError("Invalid stream name")
    stream = get_stream(stream, realm)
    if stream is None:
        raise JsonableError("Stream does not exist")
    if not stream.is_public():
        raise JsonableError("Stream is not public")
    return stream

@has_request_variables
def get_old_messages_backend(request, anchor = POST(converter=int),
                             num_before = POST(converter=to_non_negative_int),
                             num_after = POST(converter=to_non_negative_int),
                             narrow = POST('narrow', converter=narrow_parameter, default=None),
                             stream = POST(default=None),
                             user_profile=None, apply_markdown=True):
    if stream is not None:
        stream = get_public_stream(request, stream, user_profile.realm)
        recipient = get_recipient(Recipient.STREAM, stream.id)
        query = UserMessage.objects.select_related('message').filter(message__recipient=recipient,
                                                                     user_profile=user_profile) \
                                                    .order_by('id')
    else:
        query = UserMessage.objects.select_related().filter(user_profile=user_profile) \
                                                    .order_by('id')

    if narrow is not None:
        build = NarrowBuilder(user_profile)
        for operator, operand in narrow:
            query = build(query, operator, operand)

    # We add 1 to the number of messages requested to ensure that the
    # resulting list always contains the anchor message
    if num_before != 0 and num_after == 0:
        num_before += 1
        messages = last_n(num_before, query.filter(message__id__lte=anchor))
    elif num_before == 0 and num_after != 0:
        num_after += 1
        messages = query.filter(message__id__gte=anchor)[:num_after]
    else:
        num_after += 1
        messages = (last_n(num_before, query.filter(message__id__lt=anchor))
                    + list(query.filter(message__id__gte=anchor)[:num_after]))

    message_list = [dict(umessage.message.to_dict(apply_markdown),
                         **umessage.flags_dict())
                     for umessage in messages]
    ret = {'messages': message_list,
           "result": "success",
           "msg": ""}
    return json_success(ret)

def generate_client_id():
    return base64.b16encode(os.urandom(16)).lower()

@authenticated_json_post_view
def json_get_profile(request, user_profile):
    return get_profile_backend(request, user_profile)

@authenticated_api_view
def api_get_profile(request, user_profile):
    return get_profile_backend(request, user_profile)

def get_profile_backend(request, user_profile):
    result = dict(pointer        = user_profile.pointer,
                  client_id      = generate_client_id(),
                  max_message_id = -1)

    messages = Message.objects.filter(usermessage__user_profile=user_profile).order_by('-id')[:1]
    if messages:
        result['max_message_id'] = messages[0].id

    return json_success(result)

@authenticated_json_post_view
@has_request_variables
def json_update_flags(request, user_profile, messages=POST('messages', converter=json_to_list),
                                            operation=POST('op'),
                                            flag=POST('flag'),
                                            all=POST('all', converter=json_to_bool, default=False)):
    update_message_flags(user_profile, operation, flag, messages, all)
    return json_success({'result': 'success',
                         'msg': ''})

@authenticated_api_view
def api_send_message(request, user_profile):
    return send_message_backend(request, user_profile)

@authenticated_json_post_view
def json_send_message(request, user_profile):
    return send_message_backend(request, user_profile)

@authenticated_json_post_view
@has_request_variables
def json_change_enter_sends(request, user_profile, enter_sends=POST('enter_sends', json_to_bool)):
    do_change_enter_sends(user_profile, enter_sends)
    return json_success()

# Currently tabbott/extra@mit.edu is our only superuser.  TODO: Make
# this a real superuser security check.
def is_super_user_api(request):
    return request.POST.get("api-key") in ["xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"]

def mit_to_mit(user_profile, email):
    # Are the sender and recipient both @mit.edu addresses?
    # We have to handle this specially, inferring the domain from the
    # e-mail address, because the recipient may not existing in Humbug
    # and we may need to make a stub MIT user on the fly.
    if not validators.email_re.match(email):
        return False

    if user_profile.realm.domain != "mit.edu":
        return False

    domain = email.split("@", 1)[1]
    return user_profile.realm.domain == domain

def create_mirrored_message_users(request, user_profile, recipients):
    if "sender" not in request.POST:
        return (False, None)

    sender_email = request.POST["sender"].strip().lower()
    referenced_users = set([sender_email])
    if request.POST['type'] == 'private':
        for email in recipients:
            referenced_users.add(email.lower())

    # Check that all referenced users are in our realm:
    for email in referenced_users:
        if not mit_to_mit(user_profile, email):
            return (False, None)

    # Create users for the referenced users, if needed.
    for email in referenced_users:
        create_mit_user_if_needed(user_profile.realm, email)

    sender = get_user_profile_by_email(sender_email)
    return (True, sender)

@authenticated_json_post_view
@has_request_variables
def json_tutorial_send_message(request, user_profile,
                               message_type_name = POST('type'),
                               subject_name = POST('subject', lambda x: x.strip(), None),
                               message_content=POST('content')):
    """
    This function, used by the onboarding tutorial, causes the
    Tutorial Bot to send you the message you pass in here.
    (That way, the Tutorial Bot's messages to you get rendered
     by the server and therefore look like any other message.)
    """
    sender_name = "humbug+tutorial@humbughq.com"
    if message_type_name == 'private':
        # For now, we discard the recipient on PMs; the tutorial bot
        # can only send to you.
        internal_send_message(sender_name,
                              "private",
                              user_profile.user.email,
                              "",
                              message_content,
                              realm=user_profile.realm)
        return json_success()
    elif message_type_name == 'stream':
        tutorial_stream_name = 'tutorial-%s' % user_profile.user.email.split('@')[0]
        tutorial_stream_name = tutorial_stream_name[:Stream.MAX_NAME_LENGTH]
        ## TODO: For open realms, we need to use the full name here,
        ## so that me@gmail.com and me@hotmail.com don't get the same stream.
        internal_send_message(sender_name,
                              "stream",
                              tutorial_stream_name,
                              subject_name,
                              message_content,
                              realm=user_profile.realm)
        return json_success()
    return json_error('Bad data passed in to tutorial_send_message')

# We do not @require_login for send_message_backend, since it is used
# both from the API and the web service.  Code calling
# send_message_backend should either check the API key or check that
# the user is logged in.
@has_request_variables
def send_message_backend(request, user_profile,
                         message_type_name = POST('type'),
                         message_to = POST('to', converter=extract_recipients),
                         forged = POST(default=False),
                         subject_name = POST('subject', lambda x: x.strip(), None),
                         message_content = POST('content')):
    client = request.client
    is_super_user = is_super_user_api(request)
    if forged and not is_super_user:
        return json_error("User not authorized for this query")

    if client.name == "zephyr_mirror":
        # Here's how security works for non-superuser mirroring:
        #
        # The message must be (1) a private message (2) that
        # is both sent and received exclusively by other users in your
        # realm which (3) must be the MIT realm and (4) you must have
        # received the message.
        #
        # If that's the case, we let it through, but we still have the
        # security flaw that we're trusting your Hesiod data for users
        # you report having sent you a message.
        if "sender" not in request.POST:
            return json_error("Missing sender")
        if message_type_name != "private" and not is_super_user:
            return json_error("User not authorized for this query")
        (valid_input, mirror_sender) = \
            create_mirrored_message_users(request, user_profile, message_to)
        if not valid_input:
            return json_error("Invalid mirrored message")
        if user_profile.realm.domain != "mit.edu":
            return json_error("Invalid mirrored realm")
        sender = mirror_sender
    else:
        sender = user_profile

    ret = check_send_message(sender, client, message_type_name, message_to,
                             subject_name, message_content, forged=forged,
                             forged_timestamp = request.POST.get('time'),
                             forwarder_user_profile=user_profile)
    if ret is not None:
        return json_error(ret)
    return json_success()

@authenticated_api_view
def api_get_public_streams(request, user_profile):
    return get_public_streams_backend(request, user_profile)

@authenticated_json_post_view
def json_get_public_streams(request, user_profile):
    return get_public_streams_backend(request, user_profile)

def get_public_streams_backend(request, user_profile):
    if user_profile.realm.domain == "mit.edu" and not is_super_user_api(request):
        return json_error("User not authorized for this query")

    # Only get streams someone is currently subscribed to
    subs_filter = Subscription.objects.filter(active=True).values('recipient_id')
    stream_ids = Recipient.objects.filter(
        type=Recipient.STREAM, id__in=subs_filter).values('type_id')
    streams = sorted(stream.name for stream in
                     Stream.objects.filter(id__in = stream_ids,
                                           realm=user_profile.realm,
                                           invite_only=False))
    return json_success({"streams": streams})

@authenticated_api_view
def api_list_subscriptions(request, user_profile):
    return list_subscriptions_backend(request, user_profile)

@authenticated_json_post_view
def json_list_subscriptions(request, user_profile):
    return list_subscriptions_backend(request, user_profile)

def list_subscriptions_backend(request, user_profile):
    return json_success({"subscriptions": gather_subscriptions(user_profile)})

@authenticated_api_view
def api_remove_subscriptions(request, user_profile):
    return remove_subscriptions_backend(request, user_profile)

@authenticated_json_post_view
def json_remove_subscriptions(request, user_profile):
    return remove_subscriptions_backend(request, user_profile)

@has_request_variables
def remove_subscriptions_backend(request, user_profile,
                                 streams_raw = POST("subscriptions", json_to_list)):

    streams = list_to_streams(streams_raw, user_profile)

    result = dict(removed=[], not_subscribed=[])
    for stream in streams:
        did_remove = do_remove_subscription(user_profile, stream)
        if did_remove:
            result["removed"].append(stream.name)
        else:
            result["not_subscribed"].append(stream.name)

    return json_success(result)

@authenticated_api_view
def api_add_subscriptions(request, user_profile):
    return add_subscriptions_backend(request, user_profile)

@authenticated_json_post_view
def json_add_subscriptions(request, user_profile):
    return add_subscriptions_backend(request, user_profile)

@has_request_variables
def add_subscriptions_backend(request, user_profile,
                              streams_raw = POST('subscriptions', json_to_list),
                              invite_only = POST('invite_only', json_to_bool, default=False),
                              principals = POST('principals', json_to_list, default=None),):

    stream_names = []
    for stream_name in streams_raw:
        stream_name = stream_name.strip()
        if len(stream_name) > Stream.MAX_NAME_LENGTH:
            return json_error("Stream name (%s) too long." % (stream_name,))
        if not valid_stream_name(stream_name):
            return json_error("Invalid stream name (%s)." % (stream_name,))
        stream_names.append(stream_name)

    if principals is not None:
        subscribers = set(principal_to_user_profile(user_profile, principal) for principal in principals)
    else:
        subscribers = [user_profile]

    streams = list_to_streams(streams_raw, user_profile, autocreate=True, invite_only=invite_only)
    private_streams = {}
    result = dict(subscribed=[], already_subscribed=[])

    result = dict(subscribed=defaultdict(list), already_subscribed=defaultdict(list))
    for stream in streams:
        for subscriber in subscribers:
            did_subscribe = do_add_subscription(subscriber, stream)
            if did_subscribe:
                result["subscribed"][subscriber.user.email].append(stream.name)
            else:
                result["already_subscribed"][subscriber.user.email].append(stream.name)
        private_streams[stream.name] = stream.invite_only

    # Inform the user if someone else subscribed them to stuff
    if principals and result["subscribed"]:
        for email, subscriptions in result["subscribed"].iteritems():
            if email == user_profile.user.email:
                # Don't send a Humbug if you invited yourself.
                continue

            if len(subscriptions) == 1:
                msg = ("Hi there!  We thought you'd like to know that %s just "
                       "subscribed you to the%s stream '%s'"
                       % (user_profile.full_name,
                          " **invite-only**" if private_streams[subscriptions[0]] else "",
                          subscriptions[0]))
            else:
                msg = ("Hi there!  We thought you'd like to know that %s just "
                       "subscribed you to the following streams: \n\n"
                       % (user_profile.full_name,))
                for stream in subscriptions:
                    msg += "* %s%s\n" % (
                        stream,
                        " (**invite-only**)" if private_streams[stream] else "")
            internal_send_message("humbug+notifications@humbughq.com",
                                  "private", email, "", msg)

    result["subscribed"] = dict(result["subscribed"])
    result["already_subscribed"] = dict(result["already_subscribed"])
    return json_success(result)

@authenticated_api_view
def api_get_members(request, user_profile):
    return get_members_backend(request, user_profile)

@authenticated_json_post_view
def json_get_members(request, user_profile):
    return get_members_backend(request, user_profile)

def get_members_backend(request, user_profile):
    members = [(profile.full_name, profile.user.email) for profile in \
                   UserProfile.objects.select_related().filter(realm=user_profile.realm)]
    return json_success({'members': members})

@authenticated_api_view
def api_get_subscribers(request, user_profile):
    return get_subscribers_backend(request, user_profile)

@authenticated_json_post_view
def json_get_subscribers(request, user_profile):
    return get_subscribers_backend(request, user_profile)

@has_request_variables
def get_subscribers_backend(request, user_profile, stream_name=POST('stream')):
    if user_profile.realm.domain == "mit.edu":
        return json_error("You cannot get subscribers in this realm")

    stream = get_stream(stream_name, user_profile.realm)
    if stream is None:
        return json_error("Stream does not exist: %s" % stream_name)

    if stream.invite_only and not subscribed_to_stream(user_profile, stream):
        return json_error("Unable to retrieve subscribers for invite-only stream")

    subscriptions = Subscription.objects.filter(recipient__type=Recipient.STREAM,
                                                recipient__type_id=stream.id,
                                                active=True).select_related()

    return json_success({'subscribers': [subscription.user_profile.user.email
                                         for subscription in subscriptions]})

@authenticated_json_post_view
@has_request_variables
def json_change_settings(request, user_profile, full_name=POST,
                         old_password=POST, new_password=POST,
                         confirm_password=POST,
                         # enable_desktop_notification needs to default to False
                         # because browsers POST nothing for an unchecked checkbox
                         enable_desktop_notifications=POST(converter=lambda x: x == "on",
                                                           default=False)):
    if new_password != "" or confirm_password != "":
        if new_password != confirm_password:
            return json_error("New password must match confirmation password!")
        if not authenticate(username=user_profile.user.email, password=old_password):
            return json_error("Wrong password!")
        do_change_password(user_profile.user, new_password)

    result = {}
    if user_profile.full_name != full_name and full_name.strip() != "":
        do_change_full_name(user_profile, full_name.strip())
        result['full_name'] = full_name

    if user_profile.enable_desktop_notifications != enable_desktop_notifications:
        do_change_enable_desktop_notifications(user_profile, enable_desktop_notifications)
        result['enable_desktop_notifications'] = enable_desktop_notifications

    return json_success(result)

@authenticated_json_post_view
@has_request_variables
def json_stream_exists(request, user_profile, stream=POST):
    return stream_exists_backend(request, user_profile, stream)

def stream_exists_backend(request, user_profile, stream_name):
    if not valid_stream_name(stream_name):
        return json_error("Invalid characters in stream name")
    stream = get_stream(stream_name, user_profile.realm)
    result = {"exists": bool(stream)}
    if stream is not None:
        recipient = get_recipient(Recipient.STREAM, stream.id)
        result["subscribed"] = Subscription.objects.filter(user_profile=user_profile,
                                                           recipient=recipient,
                                                           active=True).exists()
        return json_success(result) # results are ignored for HEAD requests
    return json_response(data=result, status=404)

def get_subscription_or_die(stream_name, user_profile):
    stream = get_stream(stream_name, user_profile.realm)
    if not stream:
        raise JsonableError("Invalid stream %s" % (stream.name,))
    recipient = get_recipient(Recipient.STREAM, stream.id)
    subscription = Subscription.objects.filter(user_profile=user_profile,
                                               recipient=recipient, active=True)

    if not subscription.exists():
        raise JsonableError("Not subscribed to stream %s" % (stream_name,))

    return subscription

def set_in_home_view(user_profile, stream_name, value):
    subscription = get_subscription_or_die(stream_name, user_profile)[0]

    subscription.in_home_view = value
    subscription.save(update_fields=["in_home_view"])

class SubscriptionProperties(object):
    """
    A class for managing GET and POST requests for subscription properties. The
    name for a request handler is <request type>_<property name>.

    Requests must have already been authenticated before being processed here.

    Requests that set or change subscription properties should typically log the
    change through log_event.
    """

    def __call__(self, request, user_profile, property):
        property_method = getattr(self, "%s_%s" % (request.method.lower(), property), None)
        if not property_method:
            return json_error("Unknown property or invalid verb for %s" % (property,))

        return property_method(request, user_profile)

    def request_property(self, request_dict, property):
        try:
            return request_dict[property].strip()
        except KeyError:
            raise RequestVariableMissingError(property)

    def get_stream_colors(self, request, user_profile):
        return json_success({"stream_colors": get_stream_colors(user_profile)})

    def post_stream_colors(self, request, user_profile):
        stream_name = self.request_property(request.POST, "stream_name")
        color = self.request_property(request.POST, "color")

        set_stream_color(user_profile, stream_name, color)
        log_subscription_property_change(user_profile.user.email, "stream_color",
                                         {"stream_name": stream_name, "color": color})
        return json_success()

    def post_in_home_view(self, request, user_profile):
        stream_name = self.request_property(request.POST, "stream_name")
        value = self.request_property(request.POST, "in_home_view").lower()

        if value == "true":
            value = True
        elif value == "false":
            value = False
        else:
            raise JsonableError("Invalid value for `in_home_view`.")

        set_in_home_view(user_profile, stream_name, value)

        return json_success()

subscription_properties = SubscriptionProperties()

def make_property_call(request, query_dict, user_profile):
    try:
        property = query_dict["property"].strip()
    except KeyError:
        return json_error("Missing property")

    return subscription_properties(request, user_profile, property.lower())

def make_get_property_call(request, user_profile):
    return make_property_call(request, request.GET, user_profile)

def make_post_property_call(request, user_profile):
    return make_property_call(request, request.POST, user_profile)

@authenticated_json_view
def json_subscription_property(request, user_profile):
    """
    This is the entry point to accessing or changing subscription
    properties. Authentication happens here.

    Add a handler for a new subscription property in SubscriptionProperties.
    """
    if request.method == "GET":
        return make_get_property_call(request, user_profile)
    elif request.method == "POST":
        return make_post_property_call(request, user_profile)
    else:
        return json_error("Invalid verb")

@csrf_exempt
@require_post
@has_request_variables
def api_fetch_api_key(request, username=POST, password=POST):
    user = authenticate(username=username, password=password)
    if user is None:
        return json_error("Your username or password is incorrect.", status=403)
    if not user.is_active:
        return json_error("Your account has been disabled.", status=403)
    return json_success({"api_key": user.userprofile.api_key})

@authenticated_json_post_view
@has_request_variables
def json_fetch_api_key(request, user_profile, password=POST):
    if not request.user.check_password(password):
        return json_error("Your username or password is incorrect.")
    return json_success({"api_key": user_profile.api_key})

class ActivityTable(object):
    def __init__(self, client_name, queries, default_tab=False):
        self.default_tab = default_tab
        self.has_pointer = False
        self.rows = {}
        for url, query_name in queries:
            if 'pointer' in query_name:
                self.has_pointer = True
            for record in UserActivity.objects.filter(
                    query=url,
                    client__name=client_name).select_related():
                row = self.rows.setdefault(record.user_profile.user.email, {})
                row['realm'] = record.user_profile.realm.domain
                row['full_name'] = record.user_profile.full_name
                row['email'] = record.user_profile.user.email
                row[query_name + '_count'] = record.count
                row[query_name + '_last' ] = record.last_visit

        for row in self.rows.values():
            # kind of a hack
            last_action = max(v for v in row.values() if isinstance(v, datetime.datetime))
            age = now() - last_action
            if age < datetime.timedelta(minutes=10):
                row['class'] = 'recently_active'
            elif age >= datetime.timedelta(days=1):
                row['class'] = 'long_inactive'
            row['age'] = age

    def sorted_rows(self):
        return sorted(self.rows.iteritems(), key=lambda (k,r): r['age'])

def can_view_activity(request):
    return request.user.userprofile.realm.domain == 'humbughq.com'

@login_required(login_url = settings.HOME_NOT_LOGGED_IN)
def get_activity(request):
    if not can_view_activity(request):
        return HttpResponseRedirect(reverse('zephyr.views.login_page'))

    web_queries = (
        ("/json/get_updates",    "get_updates"),
        ("/json/send_message",   "send_message"),
        ("/json/update_pointer", "update_pointer"),
    )

    api_queries = (
        ("/api/v1/get_messages",  "get_updates"),
        ("/api/v1/send_message",  "send_message"),
    )

    return render_to_response('zephyr/activity.html',
        { 'data': {
            'Website': ActivityTable('website',       web_queries, default_tab=True),
            'Mirror':  ActivityTable('zephyr_mirror', api_queries),
            'API':     ActivityTable('API',           api_queries),
            'Android': ActivityTable('Android',       api_queries),
            'iPhone':  ActivityTable('iPhone',        api_queries)
        }}, context_instance=RequestContext(request))

@authenticated_api_view
@has_request_variables
def api_github_landing(request, user_profile, event=POST,
                       payload=POST(converter=json_to_dict)):
    # TODO: this should all be moved to an external bot

    repository = payload['repository']

    # CUSTOMER18 has requested not to get pull request notifications
    if event == 'pull_request' and user_profile.realm.domain not in ['customer18.invalid', 'humbughq.com']:
        pull_req = payload['pull_request']

        subject = "%s: pull request %d" % (repository['name'],
                                           pull_req['number'])
        content = ("Pull request from %s [%s](%s):\n\n %s\n\n> %s"
                   % (pull_req['user']['login'],
                      payload['action'],
                      pull_req['html_url'],
                      pull_req['title'],
                      pull_req['body']))
    elif event == 'push':
        short_ref = re.sub(r'^refs/heads/', '', payload['ref'])
        # This is a bit hackish, but is basically so that CUSTOMER18 doesn't
        # get spammed when people commit to non-master all over the place.
        # Long-term, this will be replaced by some GitHub configuration
        # option of which branches to notify on.
        if short_ref != 'master' and user_profile.realm.domain in ['customer18.invalid', 'humbughq.com']:
            return json_success()

        subject = repository['name']
        if re.match(r'^0+$', payload['after']):
            content = "%s deleted branch %s" % (payload['pusher']['name'],
                                                short_ref)
        elif len(payload['commits']) == 0:
            content = ("%s [force pushed](%s) to branch %s.  Head is now %s"
                       % (payload['pusher']['name'],
                          payload['compare'],
                          short_ref,
                          payload['after'][:7]))
        else:
            content = ("%s [pushed](%s) to branch %s\n\n"
                       % (payload['pusher']['name'],
                          payload['compare'],
                          short_ref))
            num_commits = len(payload['commits'])
            max_commits = 10
            truncated_commits = payload['commits'][:max_commits]
            for commit in truncated_commits:
                short_id = commit['id'][:7]
                (short_commit_msg, _, _) = commit['message'].partition("\n")
                content += "* [%s](%s): %s\n" % (short_id, commit['url'],
                                                 short_commit_msg)
            if (num_commits > max_commits):
                content += ("\n[and %d more commits]"
                            % (num_commits - max_commits,))
    else:
        # We don't handle other events even though we get notified
        # about them
        return json_success()

    if len(subject) > MAX_SUBJECT_LENGTH:
        subject = subject[:57].rstrip() + '...'

    request.client = get_client("github_bot")
    return send_message_backend(request, user_profile,
                                message_type_name="stream",
                                message_to=["commits"],
                                forged=False, subject_name=subject,
                                message_content=content)

@cache_with_key(lambda user_profile: user_profile.realm_id, timeout=60)
def get_status_list(requesting_user_profile):
    def presence_to_dict(presence):
        if presence.status == UserPresence.ACTIVE:
            presence_val = 'active'
        elif presence.status == UserPresence.IDLE:
            presence_val = 'idle'
        else:
            raise JsonableError("Invalid presence value in db: %s" % (presence,))

        return {'status'   : presence_val,
                'timestamp': datetime_to_timestamp(presence.timestamp)}


    user_statuses = defaultdict(dict)

    # Return no status info for MIT
    if requesting_user_profile.realm.domain == 'mit.edu':
        return {'presences': user_statuses}

    for presence in UserPresence.objects.filter(
        user_profile__realm=requesting_user_profile.realm).select_related(
        'user_profile', 'user_profile__user', 'client'):

        user_statuses[presence.user_profile.user.email][presence.client.name] = \
            presence_to_dict(presence)

    return {'presences': user_statuses}

@authenticated_json_post_view
@has_request_variables
def json_update_active_status(request, user_profile,
                              status=POST):
    if status == 'active':
        status_val = UserPresence.ACTIVE
    elif status == 'idle':
        status_val = UserPresence.IDLE
    else:
        raise JsonableError("Invalid presence status: %s" % (status,))

    update_user_presence(user_profile, request.client, now(), status_val)

    ret = get_status_list(user_profile)
    if user_profile.realm.domain == "mit.edu":
        try:
            activity = UserActivity.objects.get(user_profile = user_profile,
                                                query="/api/v1/get_messages",
                                                client__name="zephyr_mirror")
            ret['zephyr_mirror_active'] = \
                (activity.last_visit.replace(tzinfo=None) >
                 datetime.datetime.utcnow() - datetime.timedelta(minutes=5))
        except UserActivity.DoesNotExist:
            ret['zephyr_mirror_active'] = False

    return json_success(ret)

@authenticated_json_post_view
def json_get_active_statuses(request, user_profile):
    return json_success(get_status_list(user_profile))

@authenticated_json_post_view
@has_request_variables
def json_report_error(request, user_profile, message=POST, stacktrace=POST,
                      ui_message=POST(converter=json_to_bool), user_agent=POST):
    subject = "error for %s" % (user_profile.user.email,)
    if ui_message:
        subject = "User-visible browser " + subject
    else:
        subject = "Browser " + subject

    mail_admins(subject,
                "Message:\n%s\n\nStacktrace:\n%s\n\nUser agent:\n%s\n\n"
                "User saw error in UI: %s"
                % (message, stacktrace, user_agent, ui_message))
    return json_success()