class CGI::Session::FileStore

File-based session storage class.

Implements session storage as a flat file of ‘key=value’ values. This storage type only works directly with String values; the user is responsible for converting other types to Strings when storing and from Strings when retrieving.

Public Class Methods

new(session, option={}) click to toggle source

Create a new FileStore instance.

This constructor is used internally by CGI::Session. The user does not generally need to call it directly.

session is the session for which this instance is being created. The session id must only contain alphanumeric characters; automatically generated session ids observe this requirement.

option is a hash of options for the initializer. The following options are recognised:

tmpdir: the directory to use for storing the FileStore file. Defaults to Dir::tmpdir (generally “/tmp” on Unix systems).
prefix: the prefix to add to the session id when generating the filename for this session’s FileStore file. Defaults to “cgi_sid_”.
suffix: the prefix to add to the session id when generating the filename for this session’s FileStore file. Defaults to the empty string.

This session’s FileStore file will be created if it does not exist, or opened if it does.

# File cgi/session.rb, line 375
def initialize(session, option={})
  dir = option['tmpdir'] || Dir::tmpdir
  prefix = option['prefix'] || 'cgi_sid_'
  suffix = option['suffix'] || ''
  id = session.session_id
  require 'digest/md5'
  md5 = Digest::MD5.hexdigest(id)[0,16]
  @path = dir+"/"+prefix+md5+suffix
  if File::exist? @path
    @hash = nil
  else
    unless session.new_session
      raise CGI::Session::NoSession, "uninitialized session"
    end
    @hash = {}
  end
end

Public Instance Methods

close() click to toggle source

Update and close the session’s FileStore file.

# File cgi/session.rb, line 435
def close
  update
end

delete() click to toggle source

Close and delete the session’s FileStore file.

# File cgi/session.rb, line 440
def delete
  File::unlink @path+".lock" rescue nil
  File::unlink @path+".new" rescue nil
  File::unlink @path rescue nil
end

restore() click to toggle source

Restore session state from the session’s FileStore file.

Returns the session state as a hash.

# File cgi/session.rb, line 396
def restore
  unless @hash
    @hash = {}
    begin
      lockf = File.open(@path+".lock", "r")
      lockf.flock File::LOCK_SH
      f = File.open(@path, 'r')
      for line in f
        line.chomp!
        k, v = line.split('=',2)
        @hash[CGI.unescape(k)] = Marshal.restore(CGI.unescape(v))
      end
    ensure
      f&.close
      lockf&.close
    end
  end
  @hash
end

update() click to toggle source

Save session state to the session’s FileStore file.

# File cgi/session.rb, line 417
def update
  return unless @hash
  begin
    lockf = File.open(@path+".lock", File::CREAT|File::RDWR, 0600)
    lockf.flock File::LOCK_EX
    f = File.open(@path+".new", File::CREAT|File::TRUNC|File::WRONLY, 0600)
    for k,v in @hash
      f.printf "%s=%s\n", CGI.escape(k), CGI.escape(String(Marshal.dump(v)))
    end
    f.close
    File.rename @path+".new", @path
  ensure
    f&.close
    lockf&.close
  end
end