# EventSub

EventSub is a Ruby library for Twitch EventSub webhooks. It is built on the [ActiveSupport::Notifications API](http://api.rubyonrails.org/classes/ActiveSupport/Notifications.html).

This is forked from [stripe_event](https://github.com/integrallis/stripe_event) and modified for use with Twitch EventSub.

## Install

```ruby
# Gemfile
gem "eventsub"
```

```ruby
# config/routes.rb
mount EventSub::Engine, at: "/my-chosen-path"
```

## Usage

```ruby
# config/initializers/event_sub.rb
EventSub.signing_secret = ENV['TWITCH_SIGNING_SECRET']

EventSub.configure do |events|
  events.subscribe "channel.ban" do |event|
    event.subscription
    event.event
  end

  events.all do |event|
    # Handle all event types - logging, etc.
  end
end
```

### Subscriber objects that respond to #call

```ruby
class CustomerCreated
  def call(event)
    # Event handling
  end
end

class BillingEventLogger
  def initialize(logger)
    @logger = logger
  end

  def call(event)
    @logger.info "BILLING:#{event.type}:#{event.id}"
  end
end
```

```ruby
EventSub.configure do |events|
  events.all BillingEventLogger.new(Rails.logger)
  events.subscribe 'customer.created', CustomerCreated.new
end
```

## Securing your webhook endpoint

### Authenticating webhooks with signatures

Twitch will cryptographically sign webhook events with a signature which is included with a header sent with the request.
Verifying this signature lets your application properly authenticate the request originated from Twitch.

Please set the `signing_secret` configuration value:

```ruby
EventSub.signing_secret = "abc123"
```

Please refer to [Twitch's documentation](https://dev.twitch.tv/docs/eventsub/handling-webhook-events/#verifying-the-event-message) for more details

### Support for multiple signing secrets

You can also supply multiple secrets by sending an array to `signing_secrets` like so:

```ruby
EventSub.signing_secrets = [
  "abc123",
  "123abc"
]
```

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/deanpcmad/eventsub-gem.

## License

The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).