Class: CGI::Session::FileStore

Inherits:
Object
  • Object
show all
Defined in:
lib/cgi/session.rb

Overview

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.

Instance Method Summary collapse

Constructor Details

#initialize(session, option = {}) ⇒ FileStore

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.



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# File 'lib/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

Instance Method Details

#close ⇒ Object

Update and close the session’s FileStore file.



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# File 'lib/cgi/session.rb', line 435

def close
  update
end

#delete ⇒ Object

Close and delete the session’s FileStore file.



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# File 'lib/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 ⇒ Object

Restore session state from the session’s FileStore file.

Returns the session state as a hash.



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# File 'lib/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 ⇒ Object

Save session state to the session’s FileStore file.



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# File 'lib/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