Sinatra Book

一、安装
gem install sinatra
gem install thin rerun

sinatra 支持多种模板，建议选择内建的 erb 或安装 haml
gem install haml

二、Hello World 程序

require 'sinatra'
set :bind => '0.0.0.0' # 绑定到所有ip 地址

get '/' do
  "Hello world, it's #{Time.now} at the server!"
end

运行： ruby hello_world.rb 
浏览器就可以访问：

三、一些基础知识

路由 Routing ：
四种基本的 http 访问请求

• GET
• POST
• PUT
• DELETE

get '/dogs' do
  # get a listing of all the dogs
end

get '/dog/:id' do
  # just get one dog, you might find him like this:
  @dog = Dog.find(params[:id])
  # using the params convention, you specified in your route
end

post '/dog' do
  # create a new dog listing
end

put '/dog/:id' do
  # HTTP PUT request method to update an existing dog
end

delete '/dog/:id' do
  # HTTP DELETE request method to remove a dog who

route 是 sinatra 的核心内容，更多请参考： 过滤器：Filters

Sinatra 提供了一种机制，可以让你将程序通过  链入 request 请求序列中。

Filters 定义了两个方法， before 和 after ，他们后面跟一个 block，用于执行特定任务。   

before

The before method will let you pass a block to be evaluated before each and every route gets processed.

before do
  MyStore.connect unless MyStore.connected?
end

get '/' do
  @list = MyStore.find(:all)
  erb :index
end

after

The after method lets you pass a block to be evaluated after each and every route gets processed.

after do
  MyStore.disconnect
end

Pattern Matching

Filters optionally take a pattern to be matched against the requested URI during processing. Here’s a quick example you could use to run a contrived authenticate! method before accessing any “admin” type requests.

before '/admin/*' do

end

Handlers

Handlers are top-level methods available in Sinatra to take care of common HTTP routines. For instance there are handlers for and .

There are also handlers for redirection:

get '/' do
  redirect '/someplace/else'
end

This will return a 302 HTTP Response to /someplace/else.

You can even use the Sinatra handler for sessions, just add this to your application or to a configure block:

enable :sessions

Then you will be able to use the default cookie based session handler in your application:

get '/' do
  session['counter'] ||= 0
  session['counter'] += 1
  "You've hit this page #{session['counter']} times!"
end