graphql_controller.rb

# app/controllers/graphql_controller.rb
class GraphqlController < ApplicationController
  def create
    query_string = params[:query]
    query_variables = ensure_hash(params[:variables])
    context = { current_user: current_user, pundit: self }
    result = ApplicationSchema.execute(query_string, variables: query_variables, context: context)
    render json: result
  end
  
  private
  
  def ensure_hash(query_variables)
    if query_variables.blank? || query_variables == 'null'
      {}
    elsif query_variables.is_a?(String)
      JSON.parse(query_variables)
    else
      query_variables
    end
  end
end