module Tor

Returns `true` if Tor is available, `false` otherwise.

@example

Tor.available?    #=> true

@return [Boolean]

# File lib/tor.rb, line 54
def self.available?
  !!program_path
end

Returns the path to the `tor` executable, or `nil` if the program could not be found in the user's current `PATH` environment.

@example

Tor.program_path  #=> "/opt/local/bin/tor"

@param [String, to_s] program_name @return [String]

# File lib/tor.rb, line 82
def self.program_path(program_name = :tor)
  ENV['PATH'].split(File::PATH_SEPARATOR).each do |path|
    program_path = File.join(path, program_name.to_s)
    return program_path if File.executable?(program_path)
  end
  return nil
end

Returns `true` if the Tor process is running locally, `false` otherwise.

This works by attempting to establish a Tor Control Protocol (TC) connection to the standard control port 9051 on `localhost`. If Tor hasn't been configured with the `ControlPort 9051` option, this will return `false`.

@example

Tor.running?      #=> false

@return [Boolean] @since 0.1.2

# File lib/tor.rb, line 38
def self.running?
  begin
    Tor::Controller.new.quit
    true
  rescue Errno::ECONNREFUSED
    false
  end
end

Returns the Tor version number, or `nil` if Tor is not available.

@example

Tor.version       #=> "0.2.1.25"

@return [String]

# File lib/tor.rb, line 65
def self.version
  if available? && `#{program_path} --version` =~ /Tor v(\d+)\.(\d+)\.(\d+)\.(\d+)/
    [$1, $2, $3, $4].join('.')
  elsif available? && `#{program_path} --version` =~ /Tor version (\d+)\.(\d+)\.(\d+)\.(\d+)/
    [$1, $2, $3, $4].join('.')
  end
end