RingProvider uses a RingServer advertised TupleSpace as a name service. TupleSpace clients can register themselves with the remote TupleSpace and look up other provided services via the remote TupleSpace.

Services are registered with a tuple of the format [:name, klass, DRbObject, description].

A NotifyTemplateEntry is returned by TupleSpace#notify and is notified of TupleSpace changes. You may receive either your subscribed event or the ‘close’ event when iterating over notifications.

See TupleSpace#notify_event for valid notification types.

Example

ts = Rinda::TupleSpace.new
observer = ts.notify 'write', [nil]

Thread.start do
  observer.each { |t| p t }
end

3.times { |i| ts.write [i] }

Outputs:

['write', [0]]
['write', [1]]
['write', [2]]

The Tuplespace manages access to the tuples it contains, ensuring mutual exclusion requirements are met.

The sec option for the write, take, move, read and notify methods may either be a number of seconds or a Renewer object.

RSS 2.0 support

RSS has three different versions. This module contains support for version 2.0

Producing RSS 2.0

Producing our own RSS feeds is easy as well. Let’s make a very basic feed:

require "rss"

rss = RSS::Maker.make("2.0") do |maker|
  maker.channel.language = "en"
  maker.channel.author = "matz"
  maker.channel.updated = Time.now.to_s
  maker.channel.link = "http://www.ruby-lang.org/en/feeds/news.rss"
  maker.channel.title = "Example Feed"
  maker.channel.description = "A longer description of my feed."
  maker.items.new_item do |item|
    item.link = "http://www.ruby-lang.org/en/news/2010/12/25/ruby-1-9-2-p136-is-released/"
    item.title = "Ruby 1.9.2-p136 is released"
    item.updated = Time.now.to_s
  end
end

puts rss

As you can see, this is a very Builder-like DSL. This code will spit out an RSS 2.0 feed with one item. If we needed a second item, we’d make another block with maker.items.new_item and build a second one.

The basic error all other RSS errors stem from. Rescue this error if you want to handle any given RSS error and you don’t care about the details.

Since RSS is based on XML, it must have opening and closing tags that match. If they don’t, a MissingTagError will be raised.

Some tags must only exist a specific number of times in a given RSS feed. If a feed has too many occurrences of one of these tags, a TooMuchTagError will be raised.

Certain attributes are required on specific tags in an RSS feed. If a feed is missing one of these attributes, a MissingAttributeError is raised.

RSS does not allow for free-form tag names, so if an RSS feed contains a tag that we don’t know about, an UnknownTagError is raised.

Raised when an unexpected tag is encountered.

Attributes are in key-value form, and if there’s no value provided for an attribute, a NotAvailableValueError will be raised.

The command manager registers and installs all the individual sub-commands supported by the gem command.

Extra commands can be provided by writing a rubygems_plugin.rb file in an installed gem. You should register your command against the Gem::CommandManager instance, like this:

# file rubygems_plugin.rb
require 'rubygems/command_manager'

Gem::CommandManager.instance.register_command :edit

You should put the implementation of your command in rubygems/commands.

# file rubygems/commands/edit_command.rb
class Gem::Commands::EditCommand < Gem::Command
  # ...
end

See Gem::Command for instructions on writing gem commands.

Gem::ConfigFile RubyGems options and gem command options from gemrc.

gemrc is a YAML file that uses strings to match gem command arguments and symbols to match RubyGems options.

Gem command arguments use a String key that matches the command name and allow you to specify default arguments:

install: --no-rdoc --no-ri
update: --no-rdoc --no-ri

You can use gem: to set default arguments for all commands.

RubyGems options use symbol keys. Valid options are:

:backtrace

See backtrace

:sources

Sets Gem::sources

:verbose

See verbose

gemrc files may exist in various locations and are read and merged in the following order:

• system wide (/etc/gemrc)

• per user (~/.gemrc)

• per environment (gemrc files listed in the GEMRC environment variable)

Installs a gem along with all its dependencies from local and remote gems.

Raised when RubyGems is unable to load or activate a gem. Contains the name and version requirements of the gem that either conflicts with already activated gems or that RubyGems is otherwise unable to activate.

Raised when trying to activate a gem, and that gem does not exist on the system. Instead of rescuing from this class, make sure to rescue from the superclass Gem::LoadError to catch all types of load errors.