From: Chris <nemo@...>
Date: 2002-11-08T00:10:46+09:00
Subject: Re: CGI::Session::FileStore question

----- Original Message -----
|Couldn't we use marshaling and get the actual objects back?  This would
also
|make FileStore work in the same way that MemoryStore does, which seems like
|a Good Thing.
|
|Is there a reason it wasn't done this way in the first place?

Marshal may not be what you want before saving data.  So do it by
yourself, or wrap CGI::Session::FileStore to do marshaling.  It is not
too hard to define something like CGI::Session::PStore.  Sufficient
for your homework.

matz.
----------------------------

My homework?  You lost me there...

Anyway, I don't really understand why Marshal might not be a good idea.
Performance?

Plus, it still seems like FileStore and MemoryStore should be
interchangable, and they definitely aren't right now.

In any case, I threw something together which seems to work pretty well.  It
was saving and loading Fixnums, booleans, Arrays of strings... much better
than saving all of your session data in strings, IMHO.

I also added a function to Session to get the hash object, because there are
other Hash functions I would like to be able to use ('clear' and 'replace'
in particular) on the session data, and because I wanted the program logic
to be as separate as possible from the web interface.  Passing a Hash
reference seemed more orthogonal than passing a Session reference.  (I might
want to run this from other interfaces in the future.)

So this is what I add to my web scripts:


require 'cgi.rb'
require 'cgi/session.rb'
require 'html/xhtml1.rb'


class CGI
  class Session
    def getHash
      if (!@data)
        @data = @dbman.restore
      end
      @data
    end

    class FileStore
      def restore
        unless @hash
          @hash = {}
          @f.flock File::LOCK_EX
          @f.rewind
          k = nil
          for line in @f
            line.chomp!
            if (!k)
              k = line
            else
              v = Marshal::load(CGI::unescape(line))
              @hash[CGI::unescape(k)] = v
              k = nil
            end
          end
        end
        @hash
      end

      def update
        return unless @hash
        @f.rewind
        for k,v in @hash
          v = Marshal::dump(v)
          @f.printf "%s\n", CGI::escape(k)
          @f.printf "%s\n", CGI::escape(v)
        end
        @f.truncate @f.tell
      end
    end
  end
end


Thoughts?

Chris