class Gem::StreamUI

Gem::StreamUI implements a simple stream based user interface.

Attributes

errs[R]

The error stream

ins[R]

The input stream

outs[R]

The output stream

Public Class Methods

new(in_stream, out_stream, err_stream=$stderr, usetty=true) click to toggle source

Creates a new StreamUI wrapping in_stream for user input, out_stream for standard output, err_stream for error output. If usetty is true then special operations (like asking for passwords) will use the TTY commands to disable character echo.

# File rubygems/user_interaction.rb, line 196
def initialize(in_stream, out_stream, err_stream=$stderr, usetty=true)
  @ins = in_stream
  @outs = out_stream
  @errs = err_stream
  @usetty = usetty
end

Public Instance Methods

_gets_noecho() click to toggle source

# File rubygems/user_interaction.rb, line 320
def _gets_noecho
  require_io_console
  @ins.noecho { @ins.gets }
end

alert(statement, question=nil) click to toggle source

Display an informational alert. Will ask question if it is not nil.

# File rubygems/user_interaction.rb, line 335
def alert(statement, question=nil)
  @outs.puts "INFO:  #{statement}"
  ask(question) if question
end

alert_error(statement, question=nil) click to toggle source

Display an error message in a location expected to get error messages. Will ask question if it is not nil.

# File rubygems/user_interaction.rb, line 352
def alert_error(statement, question=nil)
  @errs.puts "ERROR:  #{statement}"
  ask(question) if question
end

alert_warning(statement, question=nil) click to toggle source

Display a warning on stderr. Will ask question if it is not nil.

# File rubygems/user_interaction.rb, line 343
def alert_warning(statement, question=nil)
  @errs.puts "WARNING:  #{statement}"
  ask(question) if question
end

ask(question) click to toggle source

Ask a question. Returns an answer if connected to a tty, nil otherwise.

# File rubygems/user_interaction.rb, line 284
def ask(question)
  return nil unless tty?

  @outs.print(question + "  ")
  @outs.flush

  result = @ins.gets
  result&.chomp!
  result
end

ask_for_password(question) click to toggle source

Ask for a password. Does not echo response to terminal.

# File rubygems/user_interaction.rb, line 298
def ask_for_password(question)
  return nil unless tty?

  @outs.print(question, "  ")
  @outs.flush

  password = _gets_noecho
  @outs.puts
  password&.chomp!
  password
end

ask_yes_no(question, default=nil) click to toggle source

Ask a question. Returns a true for yes, false for no. If not connected to a tty, raises an exception if default is nil, otherwise returns default.

# File rubygems/user_interaction.rb, line 249
def ask_yes_no(question, default=nil)
  unless tty?
    if default.nil?
      raise Gem::OperationNotSupportedError,
            "Not connected to a tty and no default specified"
    else
      return default
    end
  end

  default_answer = case default
                   when nil
                     "yn"
                   when true
                     "Yn"
                   else
                     "yN"
  end

  result = nil

  while result.nil? do
    result = case ask "#{question} [#{default_answer}]"
             when /^y/i then true
             when /^n/i then false
             when /^$/  then default
    end
  end

  result
end

backtrace(exception) click to toggle source

Prints a formatted backtrace to the errors stream if backtraces are enabled.

# File rubygems/user_interaction.rb, line 214
def backtrace(exception)
  return unless Gem.configuration.backtrace

  @errs.puts "\t#{exception.backtrace.join "\n\t"}"
end

choose_from_list(question, list) click to toggle source

Choose from a list of options. question is a prompt displayed above the list. list is a list of option strings. Returns the pair [option_name, option_index].

# File rubygems/user_interaction.rb, line 225
def choose_from_list(question, list)
  @outs.puts question

  list.each_with_index do |item, index|
    @outs.puts " #{index + 1}. #{item}"
  end

  @outs.print "> "
  @outs.flush

  result = @ins.gets

  return nil, nil unless result

  result = result.strip.to_i - 1
  return nil, nil unless (0...list.size) === result
  [list[result], result]
end

close() click to toggle source

# File rubygems/user_interaction.rb, line 366
def close
end

download_reporter(*args) click to toggle source

Return a download reporter object chosen from the current verbosity

# File rubygems/user_interaction.rb, line 499
def download_reporter(*args)
  if [nil, false].include?(Gem.configuration.verbose) || !@outs.tty?
    SilentDownloadReporter.new(@outs, *args)
  else
    ThreadedDownloadReporter.new(@outs, *args)
  end
end

progress_reporter(*args) click to toggle source

Return a progress reporter object chosen from the current verbosity.

# File rubygems/user_interaction.rb, line 372
def progress_reporter(*args)
  case Gem.configuration.verbose
  when nil, false
    SilentProgressReporter.new(@outs, *args)
  when true
    SimpleProgressReporter.new(@outs, *args)
  else
    VerboseProgressReporter.new(@outs, *args)
  end
end

require_io_console() click to toggle source

# File rubygems/user_interaction.rb, line 310
def require_io_console
  @require_io_console ||= begin
    begin
      require "io/console"
    rescue LoadError
    end
    true
  end
end

say(statement="") click to toggle source

Display a statement.

# File rubygems/user_interaction.rb, line 328
def say(statement="")
  @outs.puts statement
end

terminate_interaction(status = 0) click to toggle source

Terminate the application with exit code status, running any exit handlers that might have been defined.

# File rubygems/user_interaction.rb, line 361
def terminate_interaction(status = 0)
  close
  raise Gem::SystemExitException, status
end

tty?() click to toggle source

Returns true if TTY methods should be used on this StreamUI.

# File rubygems/user_interaction.rb, line 206
def tty?
  @usetty && @ins.tty?
end