Question

我显然有一个Rack :: Builder的误解。在我的config.ru文件里面我有：

require 'rack'
require 'rack/lobster'

class Shrimp
   SHRIMP_STRING = 'teste'

   def initialize(app)
      @app = app
   end

   def call(env)
     status, headers, response = @app.call(env)

     response_body = ""
     response.each { |part| response_body += part }
     response_body += "&lt;pre&gt;#{SHRIMP_STRING}&lt;/pre&gt;"

     headers["Content-Length"] = response_body.length.to_s

    [status, headers, response_body]
  end
end

app = Rack::Builder.new do
  use Rack::Lobster
  run Shrimp.new
end

Rack::Handler::WEBrick.run app

当我做的时候 rackup config.ru

我得到了

/home/vagrant/config.ru:7:in `initialize': wrong number of arguments (0 for 1) (ArgumentError)
from /home/vagrant/config.ru:26:in `new'

我错过了什么吗？根据这个tutorial Rack :: Builder.new只接收一个块作为参数。

编辑：改变这一行

run Shrimp.new

为：

run Shrimp

我仍然得到错误数量的参数，但这次是Rack :: Builder

ERROR ArgumentError: wrong number of arguments (1 for 0)
/home/vagrant/.rbenv/versions/2.0.0-p353/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/builder.rb:86:in `initialize'

Answer 1

对于Rack中间件，您不需要执行Shrimp.new，您只需执行use Shrimp即可。

您可以找到它的一个示例here.

与此链接相同，您只需执行以下操作：

# config.ru
require 'rack'
require 'rack/lobster'
require 'shrimp'      

use Shrimp            
run Rack::Lobster.new

Rack :: Builder.new上的参数数量错误

1 个答案: