From 283c630b8284e560b6f91b87ddd40645f123ff3e Mon Sep 17 00:00:00 2001
From: n9k <originalcocaineninja@protonmail.com>
Date: Sun, 3 Jul 2022 08:50:29 +0000
Subject: [PATCH] Optionally force captcha every n messages

By default every 40 messages. 0 means never force captcha in this way.
---
 anonstream/chat.py         | 7 +++++++
 anonstream/config.py       | 2 ++
 anonstream/helpers/user.py | 1 +
 anonstream/user.py         | 4 ++++
 config.toml                | 1 +
 5 files changed, 15 insertions(+)

diff --git a/anonstream/chat.py b/anonstream/chat.py
index e791221..c10fbc0 100644
--- a/anonstream/chat.py
+++ b/anonstream/chat.py
@@ -107,9 +107,16 @@ def add_chat_message(user, nonce, comment, ignore_empty=False):
     }
     MESSAGES_BY_ID[message_id] = message
 
+    # Limit number of stored messages
     while len(MESSAGES_BY_ID) > CONFIG['MAX_CHAT_MESSAGES']:
         MESSAGES_BY_ID.popitem(last=False)
 
+    # Deverify user every n messages
+    if CONFIG['CHAT_DEVERIFY_CLOCK'] is not None:
+        user['clock'] = (user['clock'] + 1) % CONFIG['CHAT_DEVERIFY_CLOCK']
+        if user['clock'] == 0:
+            user['verified'] = False
+
     # Notify event sockets that a chat message was added
     notify_event_sockets({
         'type': 'message',
diff --git a/anonstream/config.py b/anonstream/config.py
index 755d84e..8ebda05 100644
--- a/anonstream/config.py
+++ b/anonstream/config.py
@@ -119,6 +119,7 @@ def toml_to_flask_section_presence(config):
 
 def toml_to_flask_section_chat(config):
     cfg = config['chat']
+    assert cfg['force_captcha_every'] >= 0
     return {
         'CHAT_COMMENT_MAX_LENGTH': cfg['max_comment_length'],
         'CHAT_COMMENT_MAX_LINES': cfg['max_comment_lines'],
@@ -127,6 +128,7 @@ def toml_to_flask_section_chat(config):
         'CHAT_BACKGROUND_COLOUR': color_to_colour(cfg['background_color']),
         'CHAT_TRIPCODE_PASSWORD_MAX_LENGTH': cfg['max_tripcode_password_length'],
         'CHAT_LEGACY_TRIPCODE_ALGORITHM': cfg['legacy_tripcode_algorithm'],
+        'CHAT_DEVERIFY_CLOCK': cfg['force_captcha_every'] or None,
     }
 
 def toml_to_flask_section_flood(config):
diff --git a/anonstream/helpers/user.py b/anonstream/helpers/user.py
index 7bc6e63..4668d29 100644
--- a/anonstream/helpers/user.py
+++ b/anonstream/helpers/user.py
@@ -56,6 +56,7 @@ def generate_user(
             'current': {},
         },
         'headers': headers,
+        'clock': 0,
     }
 
 def get_default_name(user):
diff --git a/anonstream/user.py b/anonstream/user.py
index 021a986..c27c56e 100644
--- a/anonstream/user.py
+++ b/anonstream/user.py
@@ -174,6 +174,10 @@ def verify(user, digest, answer):
     return verification_happened
 
 def deverify(user, timestamp=None):
+    '''
+    Try to deverify a user. The user is deverified iff they have
+    exceeded the message flood threshold.
+    '''
     if timestamp is None:
         timestamp = get_timestamp()
     if user['verified'] and not user['broadcaster']:
diff --git a/config.toml b/config.toml
index bb59ee7..a12737e 100644
--- a/config.toml
+++ b/config.toml
@@ -63,6 +63,7 @@ min_name_contrast = 3.0
 background_color = "#232327"
 max_tripcode_password_length = 1024
 legacy_tripcode_algorithm = false
+force_captcha_every = 40
 
 [flood.messages]
 duration = 20.0