sinatra 扩展:

Sinatra编程的两种风格:

经典风格:

require'sinatra'

get '/' do
  "hello world"
end

模块化风格:

require'sinatra/base'

class Hello < Sinatra::Base

  get "/" do
    "hello world"
  end

  run!
end

为两种风格编写扩展:

Sinatra扩展也分为两种:

helper 型
dsl 型

helper型:

require 'sinatra/base'

module Sinatra
  module FormatHelper
    def escape_html(text)
      Rack::Utils.escape_html(text)
    end
  end

  # make sure classic style can use this extension
  helpers FormatHelper 
end

classic style 使用extension

require 'sinatra'

get '/' do
  escape_html("x > y")
end

modular style 使用extension

require 'sinatra/base'

class Hello < Sinatra::Base

  helpers Sinatra::FormatHelper

  get '/' do
    escape_html("x > y")
  end

  run!
end

dsl型:

require 'sinatra/base'

module Sinatra
  module Devise
    def authenticate!
      before {
        halt 403, "You Bastards!"
      }
    end
  end

  # make sure classic style can use this extension
  register Devise
end

classic style 使用 dsl extension

require 'sinatra'

authenticate!

get '/' do
  escape_html("x > y")
end

modular style 使用 dsl extension

require 'sinatra/base'

class Hello < Sinatra::Base
  register Sinatra::Devise

  authenticate!

  get '/' do
    "hello world"
  end

  run!
end

两种扩展可以为sinatra扩展很多东西.

例如:

actionpack的各种helpers. 可以移植到sinatra上面来.

sinatra自己的devise也是很容易通过扩展机制来实现的.

Sinatra helpers 和 register 的实现机制.

# lib/sinatra/base.rb#1772L
# Extend the top-level DSL with the modules provided.
def self.register(*extensions, &block)
  Delegator.target.register(*extensions, &block)
end

# Include the helper modules provided in Sinatra's request context.
def self.helpers(*extensions, &block)
  Delegator.target.helpers(*extensions, &block)
end

如果Delegator.target本身没有被覆盖.则为Application本身.

而Application的register方法如下:

# lib/sinatra/base.rb#1681L
def self.register(*extensions, &block) #:nodoc:
  added_methods = extensions.map {|m| m.public_instance_methods }.flatten
  Delegator.delegate(*added_methods)
  super(*extensions, &block)
end

将扩展的public_instace_methods全部抽出来了,然后给Delegator.然后delegator通过send动态调用该method.

Sinatra的helper则是直接被include至当前module或者classic模式下面的.

MRI vs JVM

JVM:

java version "1.6.0_29"

Java(TM) SE Runtime Environment (build 1.6.0_29-b11-402-11D50)

Java HotSpot(TM) 64-Bit Server VM (build 20.4-b02-402, mixed mode)

        user       system     total       real
send    0.378000   0.000000   0.378000 (  0.335000)
method  0.114000   0.000000   0.114000 (  0.114000)

MRI:

ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-darwin11.3.0]

        user       system     total       real
send    0.290000   0.000000   0.290000 (  0.284137)
method  0.280000   0.000000   0.280000 (  0.281496)

不难想象JRuby下的sinatra跑的比较慢.(暂时没有openjdk7的环境, 或许在JDK7下会跑的比较快.)

Mar 2012

Sinatra Extensions