class GraphQL::Subscriptions::ActionCableSubscriptions

A subscriptions implementation that sends data as ActionCable broadcastings.

Some things to keep in mind:

See GraphQL::Testing::MockActionCable for test helpers

Examples

Example: Adding ActionCableSubscriptions to your schema

class MySchema < GraphQL::Schema
  # ...
  use GraphQL::Subscriptions::ActionCableSubscriptions
end

Example: Implementing a channel for GraphQL Subscriptions

class GraphqlChannel < ApplicationCable::Channel
  def subscribed
    @subscription_ids = []
  end

  def execute(data)
    query = data["query"]
    variables = ensure_hash(data["variables"])
    operation_name = data["operationName"]
    context = {
      # Re-implement whatever context methods you need
      # in this channel or ApplicationCable::Channel
      # current_user: current_user,
      # Make sure the channel is in the context
      channel: self,
    }

    result = MySchema.execute(
      query,
      context: context,
      variables: variables,
      operation_name: operation_name
    )

    payload = {
      result: result.to_h,
      more: result.subscription?,
    }

    # Track the subscription here so we can remove it
    # on unsubscribe.
    if result.context[:subscription_id]
      @subscription_ids << result.context[:subscription_id]
    end

    transmit(payload)
  end

  def unsubscribed
    @subscription_ids.each { |sid|
      MySchema.subscriptions.delete_subscription(sid)
    }
  end

  private

    def ensure_hash(ambiguous_param)
      case ambiguous_param
      when String
        if ambiguous_param.present?
          ensure_hash(JSON.parse(ambiguous_param))
        else
          {}
        end
      when Hash, ActionController::Parameters
        ambiguous_param
      when nil
        {}
      else
        raise ArgumentError, "Unexpected parameter: #{ambiguous_param}"
      end
    end
end

Constants

EVENT_PREFIX
SUBSCRIPTION_PREFIX