# 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 }

# +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 = response = @app.call(env)

response[2] = BodyProxy.new(body) { log(env, status, headers, began_at) }

response

end

private

# Log the request to the configured logger.

def log(env, status, response_headers, began_at)

request = Rack::Request.new(env)

length = extract_content_length(response_headers)

msg = sprintf(FORMAT,

request.ip || "-",

request.get_header("REMOTE_USER") || "-",

Time.now.strftime("%d/%b/%Y:%H:%M:%S %z"),

request.request_method,

request.script_name,

request.path_info,

request.query_string.empty? ? "" : "?#{request.query_string}",

request.get_header(SERVER_PROTOCOL),

status.to_s[0..3],

length,

Utils.clock_time - began_at)

msg.gsub!(/[^[:print:]]/) { |c| sprintf("\\x%x", c.ord) }

msg[-1] = "\n"

logger = @logger || request.get_header(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