Formalize/tidy user presence logic

anonstream/__init__.py

@@ -31,7 +31,8 @@ async def create_app():
         'MAX_CHAT_SCROLLBACK': config['memory']['chat_scrollback'],
         'CHECKUP_PERIOD_USER': config['ratelimits']['user_absence'],
         'CHECKUP_PERIOD_CAPTCHA': config['ratelimits']['captcha_expiry'],
-        'THRESHOLD_USER_IDLE': config['thresholds']['user_idle'],
+        'THRESHOLD_USER_NOTWATCHING': config['thresholds']['user_notwatching'],
+        'THRESHOLD_USER_TENTATIVE': config['thresholds']['user_tentative'],
         'THRESHOLD_USER_ABSENT': config['thresholds']['user_absent'],
         'THRESHOLD_NOJS_CHAT_TIMEOUT': config['thresholds']['nojs_chat_timeout'],
         'CHAT_COMMENT_MAX_LENGTH': config['chat']['max_name_length'],
@@ -42,8 +43,14 @@ async def create_app():
 
     assert app.config['MAX_NOTICES'] >= 0
     assert app.config['MAX_CHAT_SCROLLBACK'] >= 0
-    assert app.config['MAX_CHAT_MESSAGES'] >= app.config['MAX_CHAT_SCROLLBACK']
-    assert app.config['THRESHOLD_USER_ABSENT'] >= app.config['THRESHOLD_USER_IDLE']
+    assert (
+        app.config['MAX_CHAT_MESSAGES'] >= app.config['MAX_CHAT_SCROLLBACK']
+    )
+    assert (
+        app.config['THRESHOLD_USER_ABSENT']
+        >= app.config['THRESHOLD_USER_TENTATIVE']
+        >= app.config['THRESHOLD_USER_NOTWATCHING']
+    )
 
     app.messages_by_id = OrderedDict()
     app.users_by_token = {}

anonstream/helpers/user.py

@@ -1,6 +1,7 @@
 import hashlib
 import base64
 from collections import OrderedDict
+from enum import Enum
 from math import inf
 
 from quart import current_app
@@ -9,6 +10,16 @@ from anonstream.utils.colour import generate_colour, colour_to_color
 
 CONFIG = current_app.config
 
+Presence = Enum(
+    'Presence',
+    names=(
+        'WATCHING',
+        'NOTWATCHING',
+        'TENTATIVE',
+        'ABSENT',
+    )
+)
+
 def generate_token_hash(token):
     parts = CONFIG['SECRET_KEY'] + b'token-hash\0' + token.encode()
     digest = hashlib.sha256(parts).digest()
@@ -29,11 +40,10 @@ def generate_user(timestamp, token, broadcaster):
         'color': colour_to_color(colour),
         'tripcode': None,
         'notices': OrderedDict(),
-        'seen': {
-            'first': timestamp,
-            'last': timestamp,
+        'last': {
+            'seen': timestamp,
+            'watching': -inf,
         },
-        'watching_last': -inf,
     }
 
 def get_default_name(user):
@@ -43,23 +53,32 @@ def get_default_name(user):
         CONFIG['DEFAULT_ANON_NAME']
     )
 
-def is_watching(timestamp, user):
-    return user['watching_last'] >= timestamp - CONFIG['THRESHOLD_USER_IDLE']
+def get_presence(timestamp, user):
+    last_watching_ago = timestamp - user['last']['watching']
+    if last_watching_ago < CONFIG['THRESHOLD_USER_NOTWATCHING']:
+        return Presence.WATCHING
 
-def is_idle(timestamp, user):
-    return is_present(timestamp, user) and not is_watching(timestamp, user)
+    last_seen_ago = timestamp - user['last']['seen']
+    if last_seen_ago < CONFIG['THRESHOLD_USER_TENTATIVE']:
+        return Presence.NOTWATCHING
+    if user['websockets']:
+        return Presence.NOTWATCHING
 
-def is_present(timestamp, user):
+    if last_seen_ago < CONFIG['THRESHOLD_USER_ABSENT']:
+        return Presence.TENTATIVE
+
+    return Presence.ABSENT
+
+def is_listed(timestamp, user):
     return (
-        user['seen']['last'] >= timestamp - CONFIG['THRESHOLD_USER_ABSENT']
-        or len(user['websockets']) > 0
+        get_presence(timestamp, user)
+        in {Presence.WATCHING, Presence.NOTWATCHING}
     )
 
-def is_absent(timestamp, user):
-    return not is_present(timestamp, user)
-
 def is_visible(timestamp, messages, user):
-    has_visible_messages = any(
-        message['token'] == user['token'] for message in messages
-    )
-    return has_visible_messages or is_present(timestamp, user)
+    def user_left_messages():
+        return any(
+            message['token'] == user['token']
+            for message in messages
+        )
+    return is_listed(timestamp, user) or user_left_messages()

anonstream/routes/wrappers.py

@@ -5,7 +5,7 @@ from functools import wraps
 from quart import current_app, request, abort, make_response, render_template, request
 from werkzeug.security import check_password_hash
 
-from anonstream.user import sunset, user_for_websocket
+from anonstream.user import sunset, see, user_for_websocket
 from anonstream.chat import broadcast
 from anonstream.helpers.user import generate_user
 from anonstream.utils.user import generate_token
@@ -71,7 +71,7 @@ def with_user_from(context):
             # Update / create user
             user = USERS_BY_TOKEN.get(token)
             if user is not None:
-                user['seen']['last'] = timestamp
+                see(user)
             else:
                 user = generate_user(
                     timestamp=timestamp,

anonstream/user.py

@@ -105,7 +105,7 @@ def delete_tripcode(user):
     user['tripcode'] = None
 
 def see(user):
-    user['seen']['last'] = int(time.time())
+    user['last']['seen'] = int(time.time())
 
 @with_timestamp
 def users_for_websocket(timestamp):

anonstream/websocket.py

@@ -6,7 +6,6 @@ from anonstream.stream import get_stream_title, get_stream_uptime
 from anonstream.chat import messages_for_websocket, add_chat_message, Rejected
 from anonstream.user import users_for_websocket, see
 from anonstream.wrappers import with_first_argument
-from anonstream.helpers.user import is_present
 from anonstream.utils.chat import generate_nonce
 from anonstream.utils.websocket import parse_websocket_data, Malformed
 

config.toml

@@ -26,6 +26,7 @@ user_absence = 8
 captcha_expiry = 8
 
 [thresholds]
-user_idle = 12
-user_absent = 1800
-nojs_chat_timeout = 24
+user_notwatching = 8
+user_tentative = 20
+user_absent = 360
+nojs_chat_timeout = 30