name : common_logger.rb # frozen_string_literal: true module Rack # Rack::CommonLogger forwards every request to the given +app+, and # logs a line in the # {Apache common log format}[http://httpd.apache.org/docs/1.3/logs.html#common] # to the configured logger. class CommonLogger # Common Log Format: http://httpd.apache.org/docs/1.3/logs.html#common # # lilith.local - - [07/Aug/2006 23:58:02 -0400] "GET / HTTP/1.1" 500 - # # %{%s - %s [%s] "%s %s%s %s" %d %s\n} % # # The actual format is slightly different than the above due to the # separation of SCRIPT_NAME and PATH_INFO, and because the elapsed # time in seconds is included at the end. FORMAT = %{%s - %s [%s] "%s %s%s%s %s" %d %s %0.4f\n} # +logger+ can be any object that supports the +write+ or +<<+ methods, # which includes the standard library Logger. These methods are called # with a single string argument, the log message. # If +logger+ is nil, CommonLogger will fall back <tt>env['rack.errors']</tt>. def initialize(app, logger = nil) @app = app @logger = logger end # Log all requests in common_log format after a response has been # returned. Note that if the app raises an exception, the request # will not be logged, so if exception handling middleware are used, # they should be loaded after this middleware. Additionally, because # the logging happens after the request body has been fully sent, any # exceptions raised during the sending of the response body will # cause the request not to be logged. def call(env) began_at = Utils.clock_time status, headers, body = @app.call(env) headers = Utils::HeaderHash[headers] body = BodyProxy.new(body) { log(env, status, headers, began_at) } [status, headers, body] end private # Log the request to the configured logger. def log(env, status, header, began_at) length = extract_content_length(header) msg = FORMAT % [ env['HTTP_X_FORWARDED_FOR'] || env["REMOTE_ADDR"] || "-", env["REMOTE_USER"] || "-", Time.now.strftime("%d/%b/%Y:%H:%M:%S %z"), env[REQUEST_METHOD], env[SCRIPT_NAME], env[PATH_INFO], env[QUERY_STRING].empty? ? "" : "?#{env[QUERY_STRING]}", env[SERVER_PROTOCOL], status.to_s[0..3], length, Utils.clock_time - began_at ] msg.gsub!(/[^[:print:]\n]/) { |c| "\\x#{c.ord}" } logger = @logger || env[RACK_ERRORS] # Standard library logger doesn't support write but it supports << which actually # calls to write on the log device without formatting if logger.respond_to?(:write) logger.write(msg) else logger << msg end end # Attempt to determine the content length for the response to # include it in the logged data. def extract_content_length(headers) value = headers[CONTENT_LENGTH] !value || value.to_s == '0' ? '-' : value end end end