From: Josef 'Jupp' SCHUGT <jupp@...>
Date: 2003-11-29T08:56:04+09:00
Subject: Re: Need library for parsing configuration files

* T. Onoma; 2003-11-28, 20:42 UTC:
> On Friday 28 November 2003 06:48 pm, Gavri Savio Fernandez wrote:
> > i'm writing an application which needs to parse a configuration
> > file on program startup. is there a prefered format for
> > configuration files in ruby? is there a library for such a
> > purpose? i suppose i could do the parsing myself, but i was just
> > wondering if there is a sophisticated way out there.
> 
> I would consider Yaml.

There are at least four ways:

- INI
- Ruby
- XML
- Yaml

INI files are very simple but also limited.

; .qvwm-theme

[Variables]
DefaultIcon         = "def16.ani"  ; titlebar/taskbar-button icon
DefaultLargeIcon    = "def32.ani"  ; task switcher icon
DefaultShortcutIcon = "icon32.ani" ; shortcut icon
DefaultFont         = "-*-*-medium-r-normal-*-14-*-*-*-*-*-*-*"

YAML has already been mentioned.

In the case of XML at least one libary exists that focusses on
configuration files.

Personally I prefer Ruby files to use other Ruby files as their
configuration files. To give an example of a config file:

Conf = {
        'stars'       =>  true,
        'host'        => 'localhost',
        'port'        =>  110,
        'user'        => 'jupp',
        'pass'        => '74!GeD,5',
        'apop'        =>  false,
        'filter'      => '/home/jupp/.popclient-filter.rb',
        'charset'     => 'ISO-8859-15',
        'statistics'  =>  true,
        'confirmation'=>  false,
        'deliver'     =>  true,
        'filerules'   => '/home/jupp/.popclient-filerules.rb',
        'logfile'     => '/home/jupp/popclient-log',
}

Actually in use, I only did change value of Conf['pass']. Parsing is
then done in this way:

def initialize(rcfile)
  rcfile = Default_rcfile if rcfile.nil?
  @rcfile = rcfile
  return unless file_okay?(rcfile, true)
  begin
    eval File.new(rcfile).read
  rescue ScriptError=>e
    warn("An error occurred while reading #{rcfile}: ", e)
  else
    @stars            = Conf['stars']
    @apop             = Conf['apop']
    @host             = Conf['host']
    @user             = Conf['user']
    @pass             = Conf['pass']
    @filter           = Conf['filter']
    @log              = Conf['logfile']
    @charset          = Conf['charset']
    @statistics       = Conf['statistics']
    @confirmation     = Conf['confirmation']
    @deliver          = Conf['deliver']
    @filerules        = Conf['filerules']

    unless Conf['port'].nil?
      port = Conf['port']
      if port < 0 or port > 65535
        warn("Invalid port in '#{rcfile}', ignored")
      else
        @port = port
      end
    end
  end
end

file_okay? does access right checking and e.g. complains about world
or group readable configuration files (which is not a good idea if
the file may contain a valuable password).

Josef 'Jupp' Schugt
-- 
begin  SPAM-POLICY.txt.vbs
if msg.size > 100 kB or msg.sender.is_spammer or msg.text.is_spam
   discard message
end