zulip/zerver/lib/notifications.py

from typing import cast, Any, Dict, Iterable, List, Mapping, Optional, Sequence, Tuple

from confirmation.models import Confirmation, create_confirmation_link
from django.conf import settings
from django.template import loader
from django.utils.timezone import now as timezone_now
from django.utils.translation import ugettext as _
from zerver.decorator import statsd_increment
from zerver.lib.send_email import send_future_email, FromAddress
from zerver.lib.queue import queue_json_publish
from zerver.models import (
    Recipient,
    ScheduledEmail,
    UserMessage,
    Stream,
    get_display_recipient,
    UserProfile,
    get_user,
    get_user_profile_by_id,
    receives_offline_email_notifications,
    get_context_for_message,
    Message,
    Realm,
)

from datetime import timedelta, datetime
from email.utils import formataddr
from lxml.cssselect import CSSSelector
import lxml.html
import re
import subprocess
import ujson
import urllib
from collections import defaultdict
import pytz

def one_click_unsubscribe_link(user_profile: UserProfile, email_type: str) -> str:
    """
    Generate a unique link that a logged-out user can visit to unsubscribe from
    Zulip e-mails without having to first log in.
    """
    return create_confirmation_link(user_profile, user_profile.realm.host,
                                    Confirmation.UNSUBSCRIBE,
                                    url_args = {'email_type': email_type})

def hash_util_encode(string: str) -> str:
    # Do the same encoding operation as hash_util.encodeHashComponent on the
    # frontend.
    # `safe` has a default value of "/", but we want those encoded, too.
    return urllib.parse.quote(
        string.encode("utf-8"), safe=b"").replace(".", "%2E").replace("%", ".")

def encode_stream(stream_id: int, stream_name: str) -> str:
    # We encode streams for urls as something like 99-Verona.
    stream_name = stream_name.replace(' ', '-')
    return str(stream_id) + '-' + hash_util_encode(stream_name)

def pm_narrow_url(realm: Realm, participants: List[str]) -> str:
    participants.sort()
    base_url = "%s/#narrow/pm-with/" % (realm.uri,)
    return base_url + hash_util_encode(",".join(participants))

def stream_narrow_url(realm: Realm, stream: Stream) -> str:
    base_url = "%s/#narrow/stream/" % (realm.uri,)
    return base_url + encode_stream(stream.id, stream.name)

def topic_narrow_url(realm: Realm, stream: Stream, topic: str) -> str:
    base_url = "%s/#narrow/stream/" % (realm.uri,)
    return "%s%s/topic/%s" % (base_url,
                              encode_stream(stream.id, stream.name),
                              hash_util_encode(topic))

def relative_to_full_url(base_url: str, content: str) -> str:
    # Convert relative URLs to absolute URLs.
    fragment = lxml.html.fromstring(content)

    # We handle narrow URLs separately because of two reasons:
    # 1: 'lxml' seems to be having an issue in dealing with URLs that begin
    # `#` due to which it doesn't add a `/` before joining the base_url to
    # the relative URL.
    # 2: We also need to update the title attribute in the narrow links which
    # is not possible with `make_links_absolute()`.
    for link_info in fragment.iterlinks():
        elem, attrib, link, pos = link_info
        match = re.match("/?#narrow/", link)
        if match is not None:
            link = re.sub(r"^/?#narrow/", base_url + "/#narrow/", link)
            elem.set(attrib, link)
            # Only manually linked narrow URLs have title attribute set.
            if elem.get('title') is not None:
                elem.set('title', link)

    # Inline images can't be displayed in the emails as the request
    # from the mail server can't be authenticated because it has no
    # user_profile object linked to it. So we scrub the inline image
    # container.
    inline_image_containers = fragment.find_class("message_inline_image")
    for container in inline_image_containers:
        container.drop_tree()

    # The previous block handles most inline images, but for messages
    # where the entire markdown input was just the URL of an image
    # (i.e. the entire body is a message_inline_image object), the
    # entire message body will be that image element; here, we need a
    # more drastic edit to the content.
    if fragment.get('class') == 'message_inline_image':
        content_template = '<p><a href="%s" target="_blank" title="%s">%s</a></p>'
        image_link = fragment.find('a').get('href')
        image_title = fragment.find('a').get('title')
        new_content = (content_template % (image_link, image_title, image_link))
        fragment = lxml.html.fromstring(new_content)

    fragment.make_links_absolute(base_url)
    content = lxml.html.tostring(fragment).decode("utf-8")

    return content

def fix_emojis(content: str, base_url: str, emojiset: str) -> str:
    def make_emoji_img_elem(emoji_span_elem: CSSSelector) -> Dict[str, Any]:
        # Convert the emoji spans to img tags.
        classes = emoji_span_elem.get('class')
        match = re.search(r'emoji-(?P<emoji_code>\S+)', classes)
        # re.search is capable of returning None,
        # but since the parent function should only be called with a valid css element
        # we assert that it does not.
        assert match is not None
        emoji_code = match.group('emoji_code')
        emoji_name = emoji_span_elem.get('title')
        alt_code = emoji_span_elem.text
        image_url = base_url + '/static/generated/emoji/images-%(emojiset)s-64/%(emoji_code)s.png' % {
            'emojiset': emojiset,
            'emoji_code': emoji_code
        }
        img_elem = lxml.html.fromstring(
            '<img alt="%(alt_code)s" src="%(image_url)s" title="%(title)s">' % {
                'alt_code': alt_code,
                'image_url': image_url,
                'title': emoji_name,
            })
        img_elem.set('style', 'height: 20px;')
        img_elem.tail = emoji_span_elem.tail
        return img_elem

    fragment = lxml.html.fromstring(content)
    for elem in fragment.cssselect('span.emoji'):
        parent = elem.getparent()
        img_elem = make_emoji_img_elem(elem)
        parent.replace(elem, img_elem)

    for realm_emoji in fragment.cssselect('.emoji'):
        del realm_emoji.attrib['class']
        realm_emoji.set('style', 'height: 20px;')

    content = lxml.html.tostring(fragment).decode('utf-8')
    return content

def build_message_list(user_profile: UserProfile, messages: List[Message]) -> List[Dict[str, Any]]:
    """
    Builds the message list object for the missed message email template.
    The messages are collapsed into per-recipient and per-sender blocks, like
    our web interface
    """
    messages_to_render = []  # type: List[Dict[str, Any]]

    def sender_string(message: Message) -> str:
        if message.recipient.type in (Recipient.STREAM, Recipient.HUDDLE):
            return message.sender.full_name
        else:
            return ''

    def fix_plaintext_image_urls(content: str) -> str:
        # Replace image URLs in plaintext content of the form
        #     [image name](image url)
        # with a simple hyperlink.
        return re.sub(r"\[(\S*)\]\((\S*)\)", r"\2", content)

    def build_message_payload(message: Message) -> Dict[str, str]:
        plain = message.content
        plain = fix_plaintext_image_urls(plain)
        # There's a small chance of colliding with non-Zulip URLs containing
        # "/user_uploads/", but we don't have much information about the
        # structure of the URL to leverage. We can't use `relative_to_full_url()`
        # function here because it uses a stricter regex which will not work for
        # plain text.
        plain = re.sub(
            r"/user_uploads/(\S*)",
            user_profile.realm.uri + r"/user_uploads/\1", plain)

        assert message.rendered_content is not None
        html = message.rendered_content
        html = relative_to_full_url(user_profile.realm.uri, html)
        html = fix_emojis(html, user_profile.realm.uri, user_profile.emojiset)

        return {'plain': plain, 'html': html}

    def build_sender_payload(message: Message) -> Dict[str, Any]:
        sender = sender_string(message)
        return {'sender': sender,
                'content': [build_message_payload(message)]}

    def message_header(user_profile: UserProfile, message: Message) -> Dict[str, Any]:
        if message.recipient.type == Recipient.PERSONAL:
            header = "You and %s" % (message.sender.full_name,)
            html_link = pm_narrow_url(user_profile.realm, [message.sender.email])
            header_html = "<a style='color: #ffffff;' href='%s'>%s</a>" % (html_link, header)
        elif message.recipient.type == Recipient.HUDDLE:
            disp_recipient = get_display_recipient(message.recipient)
            assert not isinstance(disp_recipient, str)
            other_recipients = [r['full_name'] for r in disp_recipient
                                if r['email'] != user_profile.email]
            header = "You and %s" % (", ".join(other_recipients),)
            html_link = pm_narrow_url(user_profile.realm, [r["email"] for r in disp_recipient
                                      if r["email"] != user_profile.email])
            header_html = "<a style='color: #ffffff;' href='%s'>%s</a>" % (html_link, header)
        else:
            stream = Stream.objects.only('id', 'name').get(id=message.recipient.type_id)
            header = "%s > %s" % (stream.name, message.topic_name())
            stream_link = stream_narrow_url(user_profile.realm, stream)
            topic_link = topic_narrow_url(user_profile.realm, stream, message.subject)
            header_html = "<a href='%s'>%s</a> > <a href='%s'>%s</a>" % (
                stream_link, stream.name, topic_link, message.subject)
        return {"plain": header,
                "html": header_html,
                "stream_message": message.recipient.type_name() == "stream"}

    # # Collapse message list to
    # [
    #    {
    #       "header": {
    #                   "plain":"header",
    #                   "html":"htmlheader"
    #                 }
    #       "senders":[
    #          {
    #             "sender":"sender_name",
    #             "content":[
    #                {
    #                   "plain":"content",
    #                   "html":"htmlcontent"
    #                }
    #                {
    #                   "plain":"content",
    #                   "html":"htmlcontent"
    #                }
    #             ]
    #          }
    #       ]
    #    },
    # ]

    messages.sort(key=lambda message: message.pub_date)

    for message in messages:
        header = message_header(user_profile, message)

        # If we want to collapse into the previous recipient block
        if len(messages_to_render) > 0 and messages_to_render[-1]['header'] == header:
            sender = sender_string(message)
            sender_block = messages_to_render[-1]['senders']

            # Same message sender, collapse again
            if sender_block[-1]['sender'] == sender:
                sender_block[-1]['content'].append(build_message_payload(message))
            else:
                # Start a new sender block
                sender_block.append(build_sender_payload(message))
        else:
            # New recipient and sender block
            recipient_block = {'header': header,
                               'senders': [build_sender_payload(message)]}

            messages_to_render.append(recipient_block)

    return messages_to_render

@statsd_increment("missed_message_reminders")
def do_send_missedmessage_events_reply_in_zulip(user_profile: UserProfile,
                                                missed_messages: List[Dict[str, Any]],
                                                message_count: int) -> None:
    """
    Send a reminder email to a user if she's missed some PMs by being offline.

    The email will have its reply to address set to a limited used email
    address that will send a zulip message to the correct recipient. This
    allows the user to respond to missed PMs, huddles, and @-mentions directly
    from the email.

    `user_profile` is the user to send the reminder to
    `missed_messages` is a list of dictionaries to Message objects and other data
                      for a group of messages that share a recipient (and topic)
    """
    from zerver.context_processors import common_context
    # Disabled missedmessage emails internally
    if not user_profile.enable_offline_email_notifications:
        return

    recipients = set((msg['message'].recipient_id, msg['message'].subject) for msg in missed_messages)
    if len(recipients) != 1:
        raise ValueError(
            'All missed_messages must have the same recipient and subject %r' %
            recipients
        )

    unsubscribe_link = one_click_unsubscribe_link(user_profile, "missed_messages")
    context = common_context(user_profile)
    context.update({
        'name': user_profile.full_name,
        'message_count': message_count,
        'unsubscribe_link': unsubscribe_link,
        'realm_name_in_notifications': user_profile.realm_name_in_notifications,
        'show_message_content': user_profile.message_content_in_email_notifications,
    })

    triggers = list(message['trigger'] for message in missed_messages)
    unique_triggers = set(triggers)
    context.update({
        'mention': 'mentioned' in unique_triggers,
        'mention_count': triggers.count('mentioned'),
    })

    # If this setting (email mirroring integration) is enabled, only then
    # can users reply to email to send message to Zulip. Thus, one must
    # ensure to display warning in the template.
    if settings.EMAIL_GATEWAY_PATTERN:
        context.update({
            'reply_warning': False,
            'reply_to_zulip': True,
        })
    else:
        context.update({
            'reply_warning': True,
            'reply_to_zulip': False,
        })

    from zerver.lib.email_mirror import create_missed_message_address
    reply_to_address = create_missed_message_address(user_profile, missed_messages[0]['message'])
    if reply_to_address == FromAddress.NOREPLY:
        reply_to_name = None
    else:
        reply_to_name = "Zulip"

    senders = list(set(m['message'].sender for m in missed_messages))
    if (missed_messages[0]['message'].recipient.type == Recipient.HUDDLE):
        display_recipient = get_display_recipient(missed_messages[0]['message'].recipient)
        # Make sure that this is a list of strings, not a string.
        assert not isinstance(display_recipient, str)
        other_recipients = [r['full_name'] for r in display_recipient
                            if r['id'] != user_profile.id]
        context.update({'group_pm': True})
        if len(other_recipients) == 2:
            huddle_display_name = "%s" % (" and ".join(other_recipients))
            context.update({'huddle_display_name': huddle_display_name})
        elif len(other_recipients) == 3:
            huddle_display_name = "%s, %s, and %s" % (
                other_recipients[0], other_recipients[1], other_recipients[2])
            context.update({'huddle_display_name': huddle_display_name})
        else:
            huddle_display_name = "%s, and %s others" % (
                ', '.join(other_recipients[:2]), len(other_recipients) - 2)
            context.update({'huddle_display_name': huddle_display_name})
    elif (missed_messages[0]['message'].recipient.type == Recipient.PERSONAL):
        context.update({'private_message': True})
    elif context['mention']:
        # Keep only the senders who actually mentioned the user
        senders = list(set(m['message'].sender for m in missed_messages
                           if m['trigger'] == 'mentioned'))
        # TODO: When we add wildcard mentions that send emails, we
        # should make sure the right logic applies here.
    else:
        raise AssertionError("Invalid messages!")

    # If message content is disabled, then flush all information we pass to email.
    if not user_profile.message_content_in_email_notifications:
        context.update({
            'reply_to_zulip': False,
            'messages': [],
            'sender_str': "",
            'realm_str': user_profile.realm.name,
            'huddle_display_name': "",
        })
    else:
        context.update({
            'messages': build_message_list(user_profile, list(m['message'] for m in missed_messages)),
            'sender_str': ", ".join(sender.full_name for sender in senders),
            'realm_str': user_profile.realm.name,
        })

    from_name = "Zulip missed messages"  # type: str
    from_address = FromAddress.NOREPLY
    if len(senders) == 1 and settings.SEND_MISSED_MESSAGE_EMAILS_AS_USER:
        # If this setting is enabled, you can reply to the Zulip
        # missed message emails directly back to the original sender.
        # However, one must ensure the Zulip server is in the SPF
        # record for the domain, or there will be spam/deliverability
        # problems.
        sender = senders[0]
        from_name, from_address = (sender.full_name, sender.email)
        context.update({
            'reply_warning': False,
            'reply_to_zulip': False,
        })

    email_dict = {
        'template_prefix': 'zerver/emails/missed_message',
        'to_user_id': user_profile.id,
        'from_name': from_name,
        'from_address': from_address,
        'reply_to_email': formataddr((reply_to_name, reply_to_address)),
        'context': context}
    queue_json_publish("email_senders", email_dict)

    user_profile.last_reminder = timezone_now()
    user_profile.save(update_fields=['last_reminder'])

def handle_missedmessage_emails(user_profile_id: int,
                                missed_email_events: Iterable[Dict[str, Any]]) -> None:
    message_ids = {event.get('message_id'): event.get('trigger') for event in missed_email_events}

    user_profile = get_user_profile_by_id(user_profile_id)
    if not receives_offline_email_notifications(user_profile):
        return

    messages = Message.objects.filter(usermessage__user_profile_id=user_profile,
                                      id__in=message_ids,
                                      usermessage__flags=~UserMessage.flags.read)

    # Cancel missed-message emails for deleted messages
    messages = [um for um in messages if um.content != "(deleted)"]

    if not messages:
        return

    messages_by_recipient_subject = defaultdict(list)  # type: Dict[Tuple[int, str], List[Message]]
    for msg in messages:
        if msg.recipient.type == Recipient.PERSONAL:
            # For PM's group using (recipient, sender).
            messages_by_recipient_subject[(msg.recipient_id, msg.sender_id)].append(msg)
        else:
            messages_by_recipient_subject[(msg.recipient_id, msg.topic_name())].append(msg)

    message_count_by_recipient_subject = {
        recipient_subject: len(msgs)
        for recipient_subject, msgs in messages_by_recipient_subject.items()
    }

    for msg_list in messages_by_recipient_subject.values():
        msg = min(msg_list, key=lambda msg: msg.pub_date)
        if msg.is_stream_message():
            msg_list.extend(get_context_for_message(msg))

    # Sort emails by least recently-active discussion.
    recipient_subjects = []  # type: List[Tuple[Tuple[int, str], int]]
    for recipient_subject, msg_list in messages_by_recipient_subject.items():
        max_message_id = max(msg_list, key=lambda msg: msg.id).id
        recipient_subjects.append((recipient_subject, max_message_id))

    recipient_subjects = sorted(recipient_subjects, key=lambda x: x[1])

    # Send an email per recipient subject pair
    for recipient_subject, ignored_max_id in recipient_subjects:
        unique_messages = {}
        for m in messages_by_recipient_subject[recipient_subject]:
            unique_messages[m.id] = dict(
                message=m,
                trigger=message_ids.get(m.id)
            )
        do_send_missedmessage_events_reply_in_zulip(
            user_profile,
            list(unique_messages.values()),
            message_count_by_recipient_subject[recipient_subject],
        )

def clear_scheduled_invitation_emails(email: str) -> None:
    """Unlike most scheduled emails, invitation emails don't have an
    existing user object to key off of, so we filter by address here."""
    items = ScheduledEmail.objects.filter(address__iexact=email,
                                          type=ScheduledEmail.INVITATION_REMINDER)
    items.delete()

def clear_scheduled_emails(user_id: int, email_type: Optional[int]=None) -> None:
    items = ScheduledEmail.objects.filter(user_id=user_id)
    if email_type is not None:
        items = items.filter(type=email_type)
    items.delete()

def log_digest_event(msg: str) -> None:
    import logging
    logging.basicConfig(filename=settings.DIGEST_LOG_PATH, level=logging.INFO)
    logging.info(msg)

def followup_day2_email_delay(user: UserProfile) -> timedelta:
    days_to_delay = 2
    user_tz = user.timezone
    if user_tz == '':
        user_tz = 'UTC'
    signup_day = user.date_joined.astimezone(pytz.timezone(user_tz)).isoweekday()
    if signup_day == 5:
        # If the day is Friday then delay should be till Monday
        days_to_delay = 3
    elif signup_day == 4:
        # If the day is Thursday then delay should be till Friday
        days_to_delay = 1

    # The delay should be 1 hour before the above calculated delay as
    # our goal is to maximize the chance that this email is near the top
    # of the user's inbox when the user sits down to deal with their inbox,
    # or comes in while they are dealing with their inbox.
    return timedelta(days=days_to_delay, hours=-1)

def enqueue_welcome_emails(user: UserProfile) -> None:
    from zerver.context_processors import common_context
    if settings.WELCOME_EMAIL_SENDER is not None:
        # line break to avoid triggering lint rule
        from_name = settings.WELCOME_EMAIL_SENDER['name']
        from_address = settings.WELCOME_EMAIL_SENDER['email']
    else:
        from_name = None
        from_address = FromAddress.SUPPORT

    unsubscribe_link = one_click_unsubscribe_link(user, "welcome")
    context = common_context(user)
    context.update({
        'unsubscribe_link': unsubscribe_link,
        'keyboard_shortcuts_link': user.realm.uri + '/help/keyboard-shortcuts',
    })
    if user.is_realm_admin:
        context['user_role_group'] = _('admins')
        context['getting_started_link'] = (user.realm.uri +
                                           '/help/getting-your-organization-started-with-zulip')
    else:
        context['user_role_group'] = _('members')
        context['getting_started_link'] = user.realm.uri + '/help/getting-started-with-zulip'

    send_future_email(
        "zerver/emails/followup_day1", user.realm, to_user_id=user.id, from_name=from_name,
        from_address=from_address, context=context)
    send_future_email(
        "zerver/emails/followup_day2", user.realm, to_user_id=user.id, from_name=from_name,
        from_address=from_address, context=context, delay=followup_day2_email_delay(user))

def convert_html_to_markdown(html: str) -> str:
    # On Linux, the tool installs as html2markdown, and there's a command called
    # html2text that does something totally different. On OSX, the tool installs
    # as html2text.
    commands = ["html2markdown", "html2text"]

    for command in commands:
        try:
            # A body width of 0 means do not try to wrap the text for us.
            p = subprocess.Popen(
                [command, "--body-width=0"], stdout=subprocess.PIPE,
                stdin=subprocess.PIPE, stderr=subprocess.STDOUT)
            break
        except OSError:
            continue

    markdown = p.communicate(input=html.encode('utf-8'))[0].decode('utf-8').strip()
    # We want images to get linked and inline previewed, but html2text will turn
    # them into links of the form `![](http://foo.com/image.png)`, which is
    # ugly. Run a regex over the resulting description, turning links of the
    # form `![](http://foo.com/image.png?12345)` into
    # `[image.png](http://foo.com/image.png)`.
    return re.sub("!\\[\\]\\((\\S*)/(\\S*)\\?(\\S*)\\)",
                  "[\\2](\\1/\\2)", markdown)