HelloWorld Rack程序:NoMethodError:未定义的方法`each'

Question

我正在尝试执行以下HelloWorld机架程序并收到错误.感谢任何帮助.

ruby version ruby​​ 1.9.3p448(2013-06-27)[x86_64-cygwin]

# helloworld.rb
require 'rack'
require 'rack/server'

class HelloWorld
 def response
   [200, {}, 'Hello World']
 end
end

class HelloWorldApp
 def self.call(env)
   HelloWorld.new.response
 end
end

Rack::Server.start :app => HelloWorldApp

错误

[2013-11-26 11:23:03] ERROR NoMethodError: undefined method `each' for "Hello World":String
    /usr/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/handler/webrick.rb:72:in `service'
    /usr/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
    /usr/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
    /usr/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

Answer 1

更改:

def response
  [200, {}, 'Hello World']
end

至:

def response
  [200, {}, ['Hello World']]
end