Before this, if a request was not coming from an existing user (no token
in the request or no user with the given token), then and only then
would we send the access captcha. This meant that if a user left a chat
message and became absent, they wouldn't be prompted to do the access
captcha again until their message was eventuallly rotated. (While
messages exist we don't delete the users who posted them.)
This commit makes it so if user['verified'] is None, the user is kicked
and prompted with the access captcha. This is automatically done for
absent users by a background task.
As opposed to just the broadcaster token. This makes the broadcaster
username/password login mandatory, which previously was only mandatory
in the `auth_required` wrapper, but not elsewhere (so for example
leaving comments as the broadcaster was possible with the token only). A
less safe alternative to this would be to compare tokens in `check_auth`
once the Authorization header didn't match.
This adds a field 'watching' in `user_for_websocket` that's True iff WATCHING,
False iff NOTWATCHING, and None otherwise (since clients don't need to know if
a user is tentative or absent). When the value of this field changes for any
user, they get added to the update buffer (like with any other change).
Removed race condition in `t_sunset_users`: `broadcast_users_update` was being
called *after* a user was removed from memory (and for each user being removed,
which was redundant). In that scenario if there's a user in the update buffer
and `t_sunset_users` wins the race between it and `t_broadcast_users_update`,
then when `t_sunset_users` calls `broadcast_users_update` a KeyError would be
raised since the user's already been removed.
Fixed unintended behaviour of `t_sunset_users`: it was removing users based on
the result of `is_visible`, so users who were actually tenative (as opposed to
absent) were being removed.
By default the buffer is exhausted every 4 seconds. This should defend against
a potential DoS against clients with JavaScript enabled. Before this, any
request with no token would generate a new user and immediately broadcast the
new user to all the websockets. It's best to lock down as much as possible the
number of places a client can cause the server to broadcasts to all the
websockets.
Incoming requests are handled in anonstream/routes/. Route handlers
mainly depend on files in anonstream/, which in turn depend on files in
anonstream/helpers/ and anonstream/utils/. Utils are pure functions and
helpers are almost pure functions; they don't mutate state but they
do depend on the global app config.
n9k