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={})

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 lib/cgi/session.rb, line 416
def initialize(session, option={})
  option = {'prefix' => 'cgi_sid_'}.update(option)
  @path, @hash = session.new_store_file(option)
end

Public Instance Methods

close ()

Update and close the session’s FileStore file.

# File lib/cgi/session.rb, line 463
def close
  update
end

delete ()

Close and delete the session’s FileStore file.

# File lib/cgi/session.rb, line 468
def delete
  File::unlink @path+".lock" rescue nil
  File::unlink @path+".new" rescue nil
  File::unlink @path rescue nil
end

restore ()

Restore session state from the session’s FileStore file.

Returns the session state as a hash.

# File lib/cgi/session.rb, line 424
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 ()

Save session state to the session’s FileStore file.

# File lib/cgi/session.rb, line 445
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