Kiri's Twitch Integration for Godot 4

Hiya! This is the Twitch integration I (Kiri) use for my VTuber avatar renderer.

It started off in Godot 3 as a bare minimum way for me to get my VTuber softare talking to Twitch, and then it got ported over to Godot 4 and became a little more fleshed out. But as a result, it's only really got the "throw things at my face in response to Twitch redeems and bit cheers" use case in mind, so it may need to be extended to be more useful.

Setup

It should be pretty simple to set up. Here's the rundown:

1. Make a Twitch app in the dev console.
2. Add a Redirect URL to http://localhost:3017 (localhost, port 3017, http NOT https).
3. Create a TwitchService node in your application.
4. Copy the Client ID from the Twitch console for the app to the twitch_client_id exported variable.

If everything is set up correctly and nothing else has been touched, this should automatically trigger an attempt to authenticate on startup.

User credentials are, by default, stored in "user://twitch_config.ini". It will automatically load and attempt to use these credentials on subsequent startups. This path can be changed with twitch_config_path and the functionality can be disabled by setting auto_save_credentials and auto_load_credentials.

Reacting to Twitch Events

The TwitchService node has three signals:

1. handle_channel_chat_message: Connect something to this to react to chat messages, including bit cheers.
2. handle_channel_points_redeem: Connect tis to handle point redeems. The redeem name is on of the parameters, so filter redeem events on the receiving end.
3. handle_channel_raid: Connect this to handle a raid.

Hopefully the arguments these take should be self-explanatory.

Extending It

Right now the service only selects a limited number of scopes:

1. channel:read:redemptions: Needed for point redeems.
2. chat:read: Needed for reading chat (and raids?).
3. bits:read: Needed for reacting to bit donations.

See _start_oauth_process to adjust the generated URL to modify the scopes used.

PubSub

See _client_pubsub_handle_connection_established for pubsub events that it subscribes to.

See _client_pubsub_handle_message for the code that recognizes and reacts to PubSub events.

See the Twitch documentation about PubSub for a list of topics to subscribe to.

See the Twitch documentation about scopes for a list of scopes to use when requesting the token.

IRC

See irc_inject_packet for code that reacts to incoming IRC data and emits signals.