Handling exceptions

application_controller.rb

  rescue_from StandardError do |exception|
    if request.xhr?
      render text: exception.message, :status => 500
      
    elsif request.format.json?
      err = {error: exception.message}
      err[:backtrace] = exception.backtrace.select do |line|
        # filter out non-significant lines:
        %w(/gems/ /rubygems/ /lib/ruby/).all? do |litter|
          not line.include?(litter)
        end
      end if Rails.env.development? and exception.is_a? Exception
      # duplicate exception output to console:
      STDERR.puts ["⛔️ Error:",
                   err[:error],
                   '',
                   err[:backtrace] || []].join "\n"
      render json: err, status: 500
      
    else
      raise
    end
  end