zulip/zerver/models/presence.py

109 lines
4.4 KiB
Python

from django.db import models
from django.db.models import CASCADE
from django.utils.timezone import now as timezone_now
from zerver.models.clients import Client
from zerver.models.messages import AbstractEmoji
from zerver.models.realms import Realm
from zerver.models.users import UserProfile
class UserPresence(models.Model):
"""A record from the last time we heard from a given user on a given client.
NOTE: Users can disable updates to this table (see UserProfile.presence_enabled),
so this cannot be used to determine if a user was recently active on Zulip.
The UserActivity table is recommended for that purpose.
This is a tricky subsystem, because it is highly optimized. See the docs:
https://zulip.readthedocs.io/en/latest/subsystems/presence.html
"""
user_profile = models.OneToOneField(UserProfile, on_delete=CASCADE, unique=True)
# Realm is just here as denormalization to optimize database
# queries to fetch all presence data for a given realm.
realm = models.ForeignKey(Realm, on_delete=CASCADE)
# The sequence ID within this realm for the last update to this user's presence;
# these IDs are generated by the PresenceSequence table and an important part
# of how we send incremental presence updates efficiently.
# To put it simply, every time we update a UserPresence row in a realm,
# the row gets last_update_id equal to 1 more than the previously updated
# row in that realm.
# This allows us to order UserPresence rows by when they were last updated.
last_update_id = models.PositiveBigIntegerField(db_index=True, default=0)
# The last time the user had a client connected to Zulip,
# including idle clients where the user hasn't interacted with the
# system recently (and thus might be AFK).
last_connected_time = models.DateTimeField(default=timezone_now, db_index=True, null=True)
# The last time a client connected to Zulip reported that the user
# was actually present (E.g. via focusing a browser window or
# interacting with a computer running the desktop app)
last_active_time = models.DateTimeField(default=timezone_now, db_index=True, null=True)
# The following constants are used in the presence API for
# communicating whether a user is active (last_active_time recent)
# or idle (last_connected_time recent) or offline (neither
# recent). They're no longer part of the data model.
LEGACY_STATUS_ACTIVE = "active"
LEGACY_STATUS_IDLE = "idle"
LEGACY_STATUS_ACTIVE_INT = 1
LEGACY_STATUS_IDLE_INT = 2
class Meta:
indexes = [
models.Index(
fields=["realm", "last_active_time"],
name="zerver_userpresence_realm_id_last_active_time_1c5aa9a2_idx",
),
models.Index(
fields=["realm", "last_connected_time"],
name="zerver_userpresence_realm_id_last_connected_time_98d2fc9f_idx",
),
models.Index(
fields=["realm", "last_update_id"],
name="zerver_userpresence_realm_last_update_id_idx",
),
]
@staticmethod
def status_from_string(status: str) -> int | None:
if status == "active":
return UserPresence.LEGACY_STATUS_ACTIVE_INT
elif status == "idle":
return UserPresence.LEGACY_STATUS_IDLE_INT
return None
class PresenceSequence(models.Model):
"""
This table is used to generate last_update_id values in the UserPresence table.
It serves as a per-realm sequence generator, while also facilitating
locking to avoid concurrency issues with setting last_update_id values.
Every realm has its unique row in this table, and when a UserPresence in the realm
is being updated, this row get locked against other UserPresence updates in the realm
to ensure sequential processing and set last_update_id values correctly.
"""
realm = models.OneToOneField(Realm, on_delete=CASCADE)
last_update_id = models.PositiveBigIntegerField()
class UserStatus(AbstractEmoji):
user_profile = models.OneToOneField(UserProfile, on_delete=CASCADE)
timestamp = models.DateTimeField()
client = models.ForeignKey(Client, on_delete=CASCADE)
# Override emoji_name and emoji_code field of (AbstractReaction model) to accept
# default value.
emoji_name = models.TextField(default="")
emoji_code = models.TextField(default="")
status_text = models.CharField(max_length=255, default="")