require 'singleton' require 'optparse' require 'pluginfactory' module Mongrel # Contains all of the various commands that are used with # Mongrel servers. module Command # A Command pattern implementation used to create the set of command available to the user # from Mongrel. The script uses objects which implement this interface to do the # user's bidding. # # Creating a new command is very easy, and you can do it without modifying the source # of Mongrel thanks to PluginFactory. What you do is the following: # # 1. class Command include PluginFactory attr_reader :valid, :done_validating # Called by the implemented command to set the options for that command. # Every option has a short and long version, a description, a variable to # set, and a default value. No exceptions. def options(opts) # process the given options array opts.each do |short, long, help, variable, default| self.instance_variable_set(variable, default) @opt.on(short, long, help) do |arg| self.instance_variable_set(variable, arg) end end end # Called by the subclass to setup the command and parse the argv arguments. # The call is destructive on argv since it uses the OptionParser#parse! function. def initialize(argv) @opt = OptionParser.new @valid = true # this is retarded, but it has to be done this way because -h and -v exit @done_validating = false @original_args = argv.dup configure # I need to add my own -h definition to prevent the -h by default from exiting. @opt.on_tail("-h", "--help", "Show this message") do @done_validating = true puts @opt end # I need to add my own -v definition to prevent the -h from exiting by default as well. @opt.on_tail("--version", "Show version") do @done_validating = true if VERSION puts "Version #{VERSION}" end end @opt.parse! argv end # Tells the PluginFactory where to look for additional commands. By default # it's just a "plugins" directory wherever we are located. def self.derivativeDirs return ["plugins"] end # Returns true/false depending on whether the command is configured properly. def validate return @valid end # Returns a help message. Defaults to OptionParser#help which should be good. def help @opt.help end # Runs the command doing it's job. You should implement this otherwise it will # throw a NotImplementedError as a reminder. def run raise NotImplementedError end # Validates the given expression is true and prints the message if not, exiting. def valid?(exp, message) if not @done_validating and (not exp) failure message @valid = false @done_validating = true end end # Validates that a file exists and if not displays the message def valid_exists?(file, message) valid?(file != nil && File.exist?(file), message) end # Validates that the file is a file and not a directory or something else. def valid_file?(file, message) valid?(file != nil && File.file?(file), message) end # Validates that the given directory exists def valid_dir?(file, message) valid?(file != nil && File.directory?(file), message) end # Just a simple method to display failure until something better is developed. def failure(message) STDERR.puts "!!! #{message}" end end # A Singleton class that manages all of the available commands # and handles running them. class Registry include Singleton # Builds a list of possible commands from the Command derivates list def commands list = Command.derivatives() match = Regexp.new("(.*::.*)|(.*command.*)", Regexp::IGNORECASE) results = [] list.keys.each do |key| results << key.to_s unless match.match(key.to_s) end return results.sort end # Prints a list of available commands. def print_command_list puts "Available commands are:\n\n" self.commands.each do |name| puts " - #{name}\n" end puts "\nEach command takes -h as an option to get help." end # Runs the args against the first argument as the command name. # If it has any errors it returns a false, otherwise it return true. def run(args) # find the command cmd_name = args.shift if !cmd_name or cmd_name == "?" or cmd_name == "help" print_command_list return true end # command exists, set it up and validate it begin command = Command.create(cmd_name, args) rescue FactoryError STDERR.puts "INVALID COMMAND: #$!" print_command_list return end # Normally the command is NOT valid right after being created # but sometimes (like with -h or -v) there's no further processing # needed so the command is already valid so we can skip it. if not command.done_validating if not command.validate STDERR.puts "#{cmd_name} reported an error. Use -h to get help." return false else command.run end end return true end end end end