Mini Shell

require 'rubygems/command'

class Gem::Commands::EnvironmentCommand < Gem::Command

  def initialize
    super 'environment', 'Display information about the RubyGems environment'
  end

  def arguments # :nodoc:
    args = <<-EOF
          packageversion  display the package version
          gemdir          display the path where gems are installed
          gempath         display path used to search for gems
          version         display the gem format version
          remotesources   display the remote gem servers
          platform        display the supported gem platforms
          <omitted>       display everything
    EOF
    return args.gsub(/^\s+/, '')
  end

  def description # :nodoc:
    <<-EOF
The environment command lets you query rubygems for its configuration for
use in shell scripts or as a debugging aid.

The RubyGems environment can be controlled through command line arguments,
gemrc files, environment variables and built-in defaults.

Command line argument defaults and some RubyGems defaults can be set in a
~/.gemrc file for individual users and a gemrc in the SYSTEM CONFIGURATION
DIRECTORY for all users. These files are YAML files with the following YAML
keys:

  :sources: A YAML array of remote gem repositories to install gems from
  :verbose: Verbosity of the gem command. false, true, and :really are the
            levels
  :update_sources: Enable/disable automatic updating of repository metadata
  :backtrace: Print backtrace when RubyGems encounters an error
  :gempath: The paths in which to look for gems
  :disable_default_gem_server: Force specification of gem server host on push
  <gem_command>: A string containing arguments for the specified gem command

Example:

  :verbose: false
  install: --no-wrappers
  update: --no-wrappers
  :disable_default_gem_server: true

RubyGems' default local repository can be overridden with the GEM_PATH and
GEM_HOME environment variables. GEM_HOME sets the default repository to
install into. GEM_PATH allows multiple local repositories to be searched for
gems.

If you are behind a proxy server, RubyGems uses the HTTP_PROXY,
HTTP_PROXY_USER and HTTP_PROXY_PASS environment variables to discover the
proxy server.

If you would like to push gems to a private gem server the RUBYGEMS_HOST
environment variable can be set to the URI for that server.

If you are packaging RubyGems all of RubyGems' defaults are in
lib/rubygems/defaults.rb.  You may override these in
lib/rubygems/defaults/operating_system.rb
    EOF
  end

  def usage # :nodoc:
    "#{program_name} [arg]"
  end

  def execute
    out = ''
    arg = options[:args][0]
    out <<
      case arg
      when /^packageversion/ then
        Gem::RubyGemsPackageVersion
      when /^version/ then
        Gem::VERSION
      when /^gemdir/, /^gemhome/, /^home/, /^GEM_HOME/ then
        Gem.dir
      when /^gempath/, /^path/, /^GEM_PATH/ then
        Gem.path.join(File::PATH_SEPARATOR)
      when /^remotesources/ then
        Gem.sources.to_a.join("\n")
      when /^platform/ then
        Gem.platforms.join(File::PATH_SEPARATOR)
      when nil then
        show_environment
      else
        raise Gem::CommandLineError, "Unknown environment option [#{arg}]"
      end
    say out
    true
  end

  def add_path out, path
    path.each do |component|
      out << "     - #{component}\n"
    end
  end

  def show_environment # :nodoc:
    out = "RubyGems Environment:\n"

    out << "  - RUBYGEMS VERSION: #{Gem::VERSION}\n"

    out << "  - RUBY VERSION: #{RUBY_VERSION} (#{RUBY_RELEASE_DATE}"
    out << " patchlevel #{RUBY_PATCHLEVEL}" if defined? RUBY_PATCHLEVEL
    out << ") [#{RUBY_PLATFORM}]\n"

    out << "  - INSTALLATION DIRECTORY: #{Gem.dir}\n"

    out << "  - RUBYGEMS PREFIX: #{Gem.prefix}\n" unless Gem.prefix.nil?

    out << "  - RUBY EXECUTABLE: #{Gem.ruby}\n"

    out << "  - EXECUTABLE DIRECTORY: #{Gem.bindir}\n"

    out << "  - SPEC CACHE DIRECTORY: #{Gem.spec_cache_dir}\n"

    out << "  - SYSTEM CONFIGURATION DIRECTORY: #{Gem::ConfigFile::SYSTEM_CONFIG_PATH}\n"

    out << "  - RUBYGEMS PLATFORMS:\n"
    Gem.platforms.each do |platform|
      out << "    - #{platform}\n"
    end

    out << "  - GEM PATHS:\n"
    out << "     - #{Gem.dir}\n"

    gem_path = Gem.path.dup
    gem_path.delete Gem.dir
    add_path out, gem_path

    out << "  - GEM CONFIGURATION:\n"
    Gem.configuration.each do |name, value|
      value = value.gsub(/./, '*') if name == 'gemcutter_key'
      out << "     - #{name.inspect} => #{value.inspect}\n"
    end

    out << "  - REMOTE SOURCES:\n"
    Gem.sources.each do |s|
      out << "     - #{s}\n"
    end

    out << "  - SHELL PATH:\n"

    shell_path = ENV['PATH'].split(File::PATH_SEPARATOR)
    add_path out, shell_path

    out
  end

end