From: singsang <tomsingsang@...>
Date: 2006-09-04T21:15:19+09:00
Subject: Compiling Regexp only once

Dear all,

Writing some httpd logfile pre-processing (splitting it up, getting
already some basic numbers), I think that I should compile the Regexp
for the logfile entry only once.

So my guess is that I should have perhaps a class LogFormat that holds
this as a class variable or a class constant. Below I use a non-tested
regular expression that is not complete yet.

So the idea is to have:

class LogFormat
  @@RegEx = Regexp.new( '(\S+) (\S+) (\S+) \[(\d+)/(\w+)/(\d+)
[+\-]\d+?\]' )
  def LogFormat.regex
    @@RegEx
  end
end

If now from a class LogLine (instanciated for each line in the logfile)
I use something like

class LogLine
  # ...
  ip, rfc931, user, day, month, year, offset =
line.match(LogFormat.regex)
  # ...
end

My question: How often is the Regexp compiled? When?
When the definition of LogFormat is read first?

Btw: If anybody has a ready-to-use regex for the common log format this
would be great, but I will get that done as far as I need by myself.
;-)
Other question: Does anybody know a "Webalizer" sort of thing written
in Ruby?

Thank you all so much
Herm (using a strange google account, I know)