# class Gem::Command

Base class for all Gem commands. When creating a new gem command, define initialize, execute, arguments, defaults_str, description and usage (as appropriate). See the above mentioned methods for details.

A very good example to look at is Gem::Commands::ContentsCommand

### Attributes

command[R]

The name of the command.

defaults[RW]

The default options for the command.

options[R]

The options for the command.

program_name[RW]

The name of the command for command-line invocation.

summary[RW]

A short description of the command.

### Public Class Methods

add_common_option(*args, &handler) click to toggle source

    # File lib/rubygems/command.rb, line 62
    def self.add_common_option(*args, &handler)
      Gem::Command.common_options << [args, handler]
    end

add_specific_extra_args(cmd,args) click to toggle source

Add a list of extra arguments for the given command. `args` may be an array or a string to be split on white space.

    # File lib/rubygems/command.rb, line 91
    def self.add_specific_extra_args(cmd,args)
      args = args.split(/\s+/) if args.kind_of? String
      specific_extra_args_hash[cmd] = args
    end

build_args() click to toggle source

Arguments used when building gems

    # File lib/rubygems/command.rb, line 50
    def self.build_args
      @build_args ||= []
    end

build_args=(value) click to toggle source

    # File lib/rubygems/command.rb, line 54
    def self.build_args=(value)
      @build_args = value
    end

common_options() click to toggle source

    # File lib/rubygems/command.rb, line 58
    def self.common_options
      @common_options ||= []
    end

extra_args() click to toggle source

    # File lib/rubygems/command.rb, line 66
    def self.extra_args
      @extra_args ||= []
    end

extra_args=(value) click to toggle source

    # File lib/rubygems/command.rb, line 70
    def self.extra_args=(value)
      case value
      when Array
        @extra_args = value
      when String
        @extra_args = value.split
      end
    end

new(command, summary=nil, defaults={}) click to toggle source

Initializes a generic gem command named `command`. `summary` is a short description displayed in `gem help commands`. `defaults` are the default options. Defaults should be mirrored in defaults_str, unless there are none.

When defining a new command subclass, use #add_option to add command-line switches.

Unhandled arguments (gem names, files, etc.) are left in `options[:args]`.

    # File lib/rubygems/command.rb, line 117
    def initialize(command, summary=nil, defaults={})
      @command = command
      @summary = summary
      @program_name = "gem #{command}"
      @defaults = defaults
      @options = defaults.dup
      @option_groups = Hash.new { |h,k| h[k] = [] }
      @parser = nil
      @when_invoked = nil
    end

specific_extra_args(cmd) click to toggle source

Return an array of extra arguments for the command. The extra arguments come from the gem configuration file read at program startup.

    # File lib/rubygems/command.rb, line 83
    def self.specific_extra_args(cmd)
      specific_extra_args_hash[cmd]
    end

specific_extra_args_hash() click to toggle source

Accessor for the specific extra args hash (self initializing).

    # File lib/rubygems/command.rb, line 99
    def self.specific_extra_args_hash
      @specific_extra_args_hash ||= Hash.new do |h,k|
        h[k] = Array.new
      end
    end

### Public Instance Methods

add_extra_args(args) click to toggle source

Adds extra args from ~/.gemrc

    # File lib/rubygems/command.rb, line 394
    def add_extra_args(args)
      result = []

      s_extra = Gem::Command.specific_extra_args(@command)
      extra = Gem::Command.extra_args + s_extra

      until extra.empty? do
        ex = []
        ex << extra.shift
        ex << extra.shift if extra.first.to_s =~ /^[^-]/
        result << ex if handles?(ex)
      end

      result.flatten!
      result.concat(args)
      result
    end

add_option(*opts) { |value, options| ... } click to toggle source

Add a command-line option and handler to the command.

See OptionParser#make_switch for an explanation of `opts`.

`handler` will be called with two values, the value of the argument and the options hash.

If the first argument of #add_option is a Symbol, it's used to group options in output. See `gem help list` for an example.

    # File lib/rubygems/command.rb, line 344
    def add_option(*opts, &handler) # :yields: value, options
      group_name = Symbol === opts.first ? opts.shift : :options

      @option_groups[group_name] << [opts, handler]
    end

arguments() click to toggle source

Override to provide details of the arguments a command takes. It should return a left-justified string, one argument per line.

For example:

    def usage
      "#{program_name} FILE [FILE ...]"
    end

    def arguments
      "FILE          name of file to find"
    end

    # File lib/rubygems/command.rb, line 244
    def arguments
      ""
    end

begins?(long, short) click to toggle source

True if `long` begins with the characters from `short`.

    # File lib/rubygems/command.rb, line 131
    def begins?(long, short)
      return false if short.nil?
      long[0, short.length] == short
    end

defaults_str() click to toggle source

Override to display the default values of the command options. (similar to `arguments`, but displays the default values).

For example:

    def defaults_str
      --no-gems-first --no-all
    end

    # File lib/rubygems/command.rb, line 258
    def defaults_str
      ""
    end

description() click to toggle source

Override to display a longer description of what this command does.

    # File lib/rubygems/command.rb, line 265
    def description
      nil
    end

execute() click to toggle source

Override to provide command handling.

options will be filled in with your parsed options, unparsed options will be left in `options[:args]`.

See also: get_all_gem_names, get_one_gem_name, get_one_optional_argument

    # File lib/rubygems/command.rb, line 145
    def execute
      raise Gem::Exception, "generic command has no actions"
    end

get_all_gem_names() click to toggle source

Get all gem names from the command line.

    # File lib/rubygems/command.rb, line 175
    def get_all_gem_names
      args = options[:args]

      if args.nil? or args.empty? then
        raise Gem::CommandLineError,
              "Please specify at least one gem name (e.g. gem build GEMNAME)"
      end

      args.select { |arg| arg !~ /^-/ }
    end

get_all_gem_names_and_versions() click to toggle source

Get all [gem, version] from the command line.

An argument in the form gem:ver is pull apart into the gen name and version, respectively.

    # File lib/rubygems/command.rb, line 191
    def get_all_gem_names_and_versions
      get_all_gem_names.map do |name|
        if /\A(.*):(#{Gem::Requirement::PATTERN_RAW})\z/ =~ name
          [$1, $2]
        else
          [name]
        end
      end
    end

get_one_gem_name() click to toggle source

Get a single gem name from the command line. Fail if there is no gem name or if there is more than one gem name given.

    # File lib/rubygems/command.rb, line 205
    def get_one_gem_name
      args = options[:args]

      if args.nil? or args.empty? then
        raise Gem::CommandLineError,
              "Please specify a gem name on the command line (e.g. gem build GEMNAME)"
      end

      if args.size > 1 then
        raise Gem::CommandLineError,
              "Too many gem names (#{args.join(', ')}); please specify only one"
      end

      args.first
    end

get_one_optional_argument() click to toggle source

Get a single optional argument from the command line. If more than one argument is given, return only the first. Return nil if none are given.

    # File lib/rubygems/command.rb, line 225
    def get_one_optional_argument
      args = options[:args] || []
      args.first
    end

handle_options(args) click to toggle source

Handle the given list of arguments by parsing them and recording the results.

    # File lib/rubygems/command.rb, line 384
    def handle_options(args)
      args = add_extra_args(args)
      @options = Marshal.load Marshal.dump @defaults # deep copy
      parser.parse!(args)
      @options[:args] = args
    end

handles?(args) click to toggle source

True if the command handles the given argument list.

    # File lib/rubygems/command.rb, line 371
    def handles?(args)
      begin
        parser.parse!(args.dup)
        return true
      rescue
        return false
      end
    end

invoke(*args) click to toggle source

Invoke the command with the given list of arguments.

    # File lib/rubygems/command.rb, line 289
    def invoke(*args)
      invoke_with_build_args args, nil
    end

invoke_with_build_args(args, build_args) click to toggle source

Invoke the command with the given list of normal arguments and additional build arguments.

    # File lib/rubygems/command.rb, line 297
    def invoke_with_build_args(args, build_args)
      handle_options args

      options[:build_args] = build_args

      if options[:silent]
        old_ui = self.ui
        self.ui = ui = Gem::SilentUI.new
      end

      if options[:help] then
        show_help
      elsif @when_invoked then
        @when_invoked.call options
      else
        execute
      end
    ensure
      if ui
        self.ui = old_ui
        ui.close
      end
    end

merge_options(new_options) click to toggle source

Merge a set of command options with the set of default options (without modifying the default option hash).

    # File lib/rubygems/command.rb, line 363
    def merge_options(new_options)
      @options = @defaults.clone
      new_options.each do |k,v| @options[k] = v end
    end

remove_option(name) click to toggle source

Remove previously defined command-line argument `name`.

    # File lib/rubygems/command.rb, line 353
    def remove_option(name)
      @option_groups.each do |_, option_list|
        option_list.reject! { |args, _| args.any? { |x| x =~ /^#{name}/ } }
      end
    end

show_help() click to toggle source

Display the help message for the command.

    # File lib/rubygems/command.rb, line 281
    def show_help
      parser.program_name = usage
      say parser
    end

show_lookup_failure(gem_name, version, errors, domain) click to toggle source

Display to the user that a gem couldn't be found and reasons why

    # File lib/rubygems/command.rb, line 154
    def show_lookup_failure(gem_name, version, errors, domain)
      if errors and !errors.empty?
        msg = "Could not find a valid gem '#{gem_name}' (#{version}), here is why:\n".dup
        errors.each { |x| msg << "          #{x.wordy}\n" }
        alert_error msg
      else
        alert_error "Could not find a valid gem '#{gem_name}' (#{version}) in any repository"
      end

      unless domain == :local then # HACK
        suggestions = Gem::SpecFetcher.fetcher.suggest_gems_from_name gem_name

        unless suggestions.empty?
          alert_error "Possible alternatives: #{suggestions.join(", ")}"
        end
      end
    end

usage() click to toggle source

Override to display the usage for an individual gem command.

The text “[options]” is automatically appended to the usage text.

    # File lib/rubygems/command.rb, line 274
    def usage
      program_name
    end

when_invoked(&block) click to toggle source

Call the given block when invoked.

Normal command invocations just executes the `execute` method of the command. Specifying an invocation block allows the test methods to override the normal action of a command to determine that it has been invoked correctly.

    # File lib/rubygems/command.rb, line 329
    def when_invoked(&block)
      @when_invoked = block
    end

### Private Instance Methods

add_parser_run_info(title, content) click to toggle source

Adds a section with `title` and `content` to the parser help view. Used for adding command arguments and default arguments.

    # File lib/rubygems/command.rb, line 445
    def add_parser_run_info title, content
      return if content.empty?

      @parser.separator nil
      @parser.separator "  #{title}:"
      content.split(/\n/).each do |line|
        @parser.separator "    #{line}"
      end
    end

configure_options(header, option_list) click to toggle source

    # File lib/rubygems/command.rb, line 491
    def configure_options(header, option_list)
      return if option_list.nil? or option_list.empty?

      header = header.to_s.empty? ? '' : "#{header} "
      @parser.separator "  #{header}Options:"

      option_list.each do |args, handler|
        args.select { |arg| arg =~ /^-/ }
        @parser.on(*args) do |value|
          handler.call(value, @options)
        end
      end

      @parser.separator ''
    end

create_option_parser() click to toggle source

Creates an option parser and fills it in with the help info for the command.

    # File lib/rubygems/command.rb, line 477
    def create_option_parser
      @parser = OptionParser.new

      add_parser_options

      @parser.separator nil
      configure_options "Common", Gem::Command.common_options

      add_parser_run_info "Arguments", arguments
      add_parser_summary
      add_parser_description
      add_parser_run_info "Defaults", defaults_str
    end

parser() click to toggle source

Create on demand parser.

    # File lib/rubygems/command.rb, line 468
    def parser
      create_option_parser if @parser.nil?
      @parser
    end

wrap(text, width) click to toggle source

Wraps `text` to `width`

    # File lib/rubygems/command.rb, line 510
    def wrap(text, width) # :doc:
      text.gsub(/(.{1,#{width}})( +|$\n?)|(.{1,#{width}})/, "\\1\\3\n")
    end