Use OptionParser for parsing command line options

Author: Chris Hunt

Rakefile

@@ -12,6 +12,7 @@ desc 'Check code quality'
 Cane::RakeTask.new(:quality) do |task|
   task.abc_max = 9
   task.use Cane::HashCheck
+  task.abc_exclude = %w(Auth::Options#initialize)
 end
 
 task default: :spec

bin/gh-auth

@@ -2,4 +2,4 @@
 
 require 'github/auth'
 
-Github::Auth::CLI.new(ARGV).execute
+Github::Auth::CLI.new.execute(ARGV)

lib/github/auth.rb

@@ -2,4 +2,5 @@
 require 'github/auth/key'
 require 'github/auth/keys_client'
 require 'github/auth/keys_file'
+require 'github/auth/options'
 require 'github/auth/cli'

lib/github/auth/cli.rb

@@ -1,43 +1,21 @@
 module Github::Auth
   # Command Line Interface for parsing and executing commands
   class CLI
-    attr_reader :command, :usernames
+    attr_reader :options
 
-    COMMANDS = %w(add remove list)
-
-    def initialize(argv)
-      @command   = argv.shift
-      @usernames = argv
-    end
-
-    def execute
-      if COMMANDS.include?(command)
-        send command
-      elsif command == '--version'
-        puts "gh-auth version #{Github::Auth::VERSION}"
-      else
-        print_usage
-      end
+    def execute(args)
+      @options = Options.new.parse(args)
+      send options.command
     end
 
     private
 
     def add
-      if usernames.empty?
-        print_usage
-        return
-      end
-
       on_keys_file :write!,
         "Adding #{keys.count} key(s) to '#{keys_file.path}'"
     end
 
     def remove
-      if usernames.empty?
-        print_usage
-        return
-      end
-
       on_keys_file :delete!,
         "Removing #{keys.count} key(s) from '#{keys_file.path}'"
     end
@@ -46,6 +24,14 @@ def list
       puts "Added users: #{keys_file.github_users.join(', ')}"
     end
 
+    def version
+      puts Github::Auth::VERSION
+    end
+
+    def usage
+      puts options.usage
+    end
+
     def on_keys_file(action, message)
       puts message
       rescue_keys_file_errors { keys_file.send action, keys }
@@ -65,12 +51,8 @@ def rescue_keys_file_errors
       puts "  $ touch #{keys_file.path}"
     end
 
-    def print_usage
-      puts "usage: gh-auth [--version] [#{COMMANDS.join '|'}] <username>"
-    end
-
     def keys
-      @keys ||= usernames.map { |username| keys_for username }.flatten.compact
+      @keys ||= options.usernames.map { |user| keys_for user }.flatten.compact
     end
 
     def keys_for(username)

lib/github/auth/options.rb

@@ -0,0 +1,65 @@
+require 'optparse'
+
+module Github::Auth
+  # Parses command line options
+  class Options
+    attr_reader :parser
+
+    def initialize
+      @parser = OptionParser.new do |opts|
+        opts.banner = [
+          'usage: gh-auth',
+          '[--version]',
+          '[add|remove|list]',
+          '<username>'
+        ].join(' ')
+
+        opts.separator "\noptions:"
+
+        opts.on(
+          '--add doug,sally', Array,
+          "GitHub user(s) you'd like to add"
+        ) do |usernames|
+          raise OptionParser::MissingArgument if usernames.empty?
+          @command = 'add'
+          @usernames = usernames
+        end
+
+        opts.on(
+          '--remove doug,sally', Array,
+          "GitHub user(s) you'd like to remove"
+        ) do |usernames|
+          raise OptionParser::MissingArgument if usernames.empty?
+          @command = 'remove'
+          @usernames = usernames
+        end
+
+        opts.on('--list', "List all GitHub users you've added") do
+          @command = 'list'
+        end
+
+        opts.on('--version', 'Show version') do
+          @command = 'version'
+        end
+      end
+    end
+
+    def command
+      @command ||= 'usage'
+    end
+
+    def usernames
+      @usernames ||= []
+    end
+
+    def usage
+      parser.help
+    end
+
+    def parse(args)
+      parser.parse(args)
+    ensure
+      return self
+    end
+  end
+end

spec/acceptance/github/auth/cli_spec.rb

@@ -11,8 +11,8 @@
 
     after { keys_file.unlink }
 
-    def cli(argv)
-      described_class.new(argv).tap do |cli|
+    def cli
+      described_class.new.tap do |cli|
         cli.stub(
           github_hostname: hostname,
           keys_file_path: keys_file.path
@@ -21,41 +21,41 @@ def cli(argv)
     end
 
     it 'adds and removes keys from the keys file' do
-      cli(%w(add chrishunt)).execute
+      cli.execute %w(--add chrishunt)
 
       keys_file.read.tap do |keys_file_content|
         keys.each { |key| expect(keys_file_content).to include key.to_s }
       end
 
-      cli(%w(remove chrishunt)).execute
+      cli.execute %w(--remove chrishunt)
 
       expect(keys_file.read).to be_empty
 
       keys_file.unlink
     end
 
     it 'lists users from the keys file' do
-      cli(%w(add chrishunt)).execute
+      cli.execute %w(--add chrishunt)
 
       output = capture_stdout do
-        cli(%w(list)).execute
+        cli.execute %w(--list)
       end
 
       expect(output).to include('chrishunt')
     end
 
     it 'prints version information' do
       output = capture_stdout do
-        cli(%w(--version)).execute
+        cli.execute %w(--version)
       end
 
       expect(output).to include Github::Auth::VERSION
     end
 
     it 'prints usage for invalid arguments' do
-      [[], %w(invalid), %w(add)].each do |invalid_arguments|
+      [[], %w(invalid), %w(--add)].each do |invalid_arguments|
         expect(
-          capture_stdout { cli(invalid_arguments).execute }
+          capture_stdout { cli.execute invalid_arguments }
         ).to include 'usage: gh-auth'
       end
     end