stefan-kolb/nucleus

module Nucleus
  module API
    module Middleware
      # The {Nucleus::Middleware::ErrorRequestLogger} is assigned to redirect the
      # default 'rack.errors' output not only to the console, but also to a log file.
      # This file then includes all error stacktraces.
      #
      # @author Cedric Roeck (cedric.roeck@gmail.com)
      # @since 0.1.0
      class ErrorRequestLogger
        def initialize(app, file)
          @app = app
          @file = file
        end

        def call(env)
          # create the error logger
          error_logger = File.new(@file, 'a+')
          error_logger.sync = true
          # assign dispatcher to be used for printing errors
          dispatcher = ErrorRequestDispatcher.new([error_logger, env['rack.errors']])
          env['rack.errors'] = dispatcher
          # execute call
          status, headers, body = @app.call(env)
          # send the response
          [status, headers, body]
        end
      end

      # Dispatch the call (write << puts p pp) to all loggers
      class ErrorRequestDispatcher
        def initialize(loggers)
          @loggers = loggers
        end

        def puts(msg)
          @loggers.each do |logger|
            logger.puts(msg) if logger.respond_to?(:puts)
          end
        end

        def write(msg)
          @loggers.each do |logger|
            logger.write(msg) if logger.respond_to?(:write)
          end
        end

        def <<(msg)
          @loggers.each do |logger|
            logger << msg if logger.respond_to?(:<<)
          end
        end

        def flush
          @loggers.each do |logger|
            logger.flush if logger.respond_to?(:flush)
          end
        end
      end
    end
  end
end