Using pluginfactory along with original command code from fastcst.

git-svn-id: svn+ssh://rubyforge.org/var/svn/mongrel/trunk@31 19e92222-5c0b-0410-8929-a290d50e31e9

1 files changed, 201 insertions, 0 deletions

diff --git a/lib/mongrel/command.rb b/lib/mongrel/command.rb
new file mode 100644
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+++ b/lib/mongrel/command.rb
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+require 'singleton'
+require 'optparse'
+require 'pluginfactory'
+
+
+module Mongrel
+  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.
+    #
+    # Implementing a command is fairly easy.  Refer to some of the stock commands in the 
+    # lib/mongrel/command directory for examples.
+    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
+
+        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
+          puts "No version yet."
+        end
+        
+        @opt.parse! argv
+      end
+      
+      # Tells the PluginFactory where to look for additional commands.  By default
+      # it's just a "mongrel" directory wherever we are located.
+      def self.derivativeDirs
+        return ["mongrel"]
+      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)
+          STDERR.puts 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
+    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 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"
+        
+        self.commands.each do |name|
+          puts " - #{name}\n"
+        end
+        
+        puts "Each 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 and change the program's name to reflect it
+        cmd_name = args.shift
+        $0 = "#{cmd_name}"
+        
+        if 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 :command, "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 :command, "#{cmd_name} reported an error. Use -h to get help."
+            return false
+          else
+            command.run
+          end
+        end
+        return true
+      end
+      
+      # Runs the command like normal, but redirects $stdout and $stderr to the
+      # requested log file (which should be a file like object opened by you).
+      # It also marks the start and end times in the log file.
+      def run_redirect(log, args)
+        res = false
+        
+        begin
+          oldstdout = $stdout
+          oldstderr = $stderr
+          
+          log.write ">>>>>> #{Time.now}\n"
+          $stdout = log
+          $stderr = log
+          
+          res = run(args)
+          
+          log.write "<<<<<< #{Time.now}\n"
+          
+        ensure
+          $stdout = oldstdout
+          $stderr = oldstderr
+          return res
+        end
+      end
+    end
+  end
+end
+