chatterino2/lib/twitch-eventsub-ws/src/payloads

Adding a new subscription type

The example will use channel.update on version 1.

Create the header & source files

Replace channel-update/channel_update with your dashed & underscored subscription names

Header file include/twitch-eventsub-ws/payloads/channel-update-v1.hpp:

#pragma once

#include "twitch-eventsub-ws/payloads/subscription.hpp"

#include <boost/json.hpp>

#include <string>

namespace chatterino::eventsub::lib::payload::channel_update::v1 {

/// json_transform=snake_case
struct Event {
    // TODO: Fill in your subscription-specific event here
};

struct Payload {
    const subscription::Subscription subscription;

    const Event event;
};

// DESERIALIZATION DEFINITION START
// DESERIALIZATION DEFINITION END

}  // namespace chatterino::eventsub::lib::payload::channel_update::v1

Source file:

#include "twitch-eventsub-ws/payloads/channel-update-v1.hpp"

#include "twitch-eventsub-ws/errors.hpp"

#include <boost/json.hpp>

namespace chatterino::eventsub::lib::payload::channel_update::v1 {

// DESERIALIZATION IMPLEMENTATION START
// DESERIALIZATION IMPLEMENTATION END

}  // namespace chatterino::eventsub::lib::payload::channel_update::v1

Run the generation script

In the root dir of the repostitory, type make in your terminal.

If you can't do that, run the generate-and-replace-dir.py script manually (e.g. ./ast/generate-and-replace-dir.py ./src/payloads)

Add the source file to src/CMakeLists.txt

Look for the # Add your new subscription type source file above this line comment and add the source file above that line.

In my example, I added the following line:
payloads/channel-update-v1.cpp

Add a virtual method to the Listener class in include/twitch-eventsub-ws/listener.hpp

Look for the // Add your new subscription types above this line comment and add your definition above that line.

In my example, I added the following code:

    virtual void onChannelUpdate(
        messages::Metadata metadata,
        payload::channel_update::v1::Payload payload) = 0;

You also need to add an include to your header file

In my example, I added the following code at the top of the file:

#include "twitch-eventsub-ws/payloads/channel-update-v1.hpp"

Add a handler for the subscription type in src/session.cpp

Look for the // Add your new subscription types above this line comment and add your code above that line.

In my example, I added the following code:

    {
        {"channel.update", "1"},
        [](const auto &metadata, const auto &jv, auto &listener) {
            auto oPayload =
                parsePayload<eventsub::payload::channel_update::v1::Payload>(
                    jv);
            if (!oPayload)
            {
                return;
            }
            listener->onChannelUpdate(metadata, *oPayload);
        },
    },

Make the test code work in example/main.cpp

Look for the // Add your new subscription types above this line comment and add your code above that line.

In my example, I added the following code:

    void onChannelUpdate(messages::Metadata metadata,
                         payload::channel_update::v1::Payload payload) override
    {
        std::cout << "Channel update event!\n";
    }

Full PR that does this: https://github.com/pajlada/beast-websocket-client/pull/19/files

TODO: Add step for how to verify this using the Twitch CLI, realistically though this will differ from subscription to subscription. Some are simpler than others