Rails版本区别

1. 脚本命令

旧的命令 新的用法

script/generate rails g

script/console rails c

script/server rails s

script/dbconsole rails db

2. 配置文件

rails2:config/environment.rb

Rails::Initializer.run
do
|config|
config.load_paths+=%W(#{RAILS_ROOT}/extras)
config.gem"bj"
config.gem"sqlite3-ruby"
,
:lib
=>
"sqlite3"
config.gem"aws-s3"
,
:lib
=>
"aws/s3"
config.plugins=[:exception_notification
]
config.time_zone='UTC'
end

Rails::Initializer.run do |config|
    config.load_paths += %W( #{RAILS_ROOT}/extras )
    config.gem "bj"
    config.gem "sqlite3-ruby", :lib => "sqlite3"
    config.gem "aws-s3", :lib => "aws/s3"
    config.plugins = [ :exception_notification ]
    config.time_zone = 'UTC'
end

rails3:config/application.rb

module
APP_NAME
class
Application<Rails::Application
config.load_paths+=%W(#{RAILS_ROOT}/extras)
config.plugins=[:exception_notification
]
config.time_zone='UTC'
end
end

module APP_NAME
    class Application < Rails::Application
        config.load_paths += %W( #{RAILS_ROOT}/extras )
        config.plugins = [ :exception_notification ]
        config.time_zone = 'UTC'
    end
end

这样就变成了一种架构式的应用, 我们可以根据方便的对config进行操作

3. 路由

在rails3中, 已经的路由可以继续工作, 而新的路由方式更加简洁.

在 rails2 中:

map.resources
:posts

do
|post|
post.resources:comments
end

map.resources :posts do |post|
    post.resources :comments
end

而在rails3中 , 表达更为形象:

resources
:posts

do
resources:comments
end

resources :posts do
    resources :comments
end

对于一些复杂的路由, rails2:

post.resources
:comments
,
:member
=>{
:preview
=>
:post
},
:collection
=>{
:archived
=>
:get
}

post.resources :comments,
                 :member => { :preview => :post },
                 :collection => { :archived => :get }

在 rails3中可以这样表达:

resources
:comments

do
memberdo
post:preview
end
collectiondo
get:archived
end
end

resources :comments do
    member do
        post :preview
    end
    collection do
        get :archived
    end
end

不够简洁? 我们还可以这样做:

resources
:comments

do
post:preview
,
:on
=>
:member
get:archived
,
:on
=>
:collection
end

resources :comments do
    post :preview, :on => :member
    get :archived, :on => :collection
end

对于基本路由, rails2:

map.connect
'login'
,
:controller
=>
'session'
,
:action
=>
'new'

map.connect 'login', :controller => 'session', :action => 'new'

那么在rails3中:

match
'login'
=>
'session#new'

match 'login' => 'session#new'

对于具名路由, rails2:

map.login
'login'
,
:controller
=>
'session'
,
:action
=>
'new'

map.login 'login', :controller => 'session', :action => 'new'

在rails3中:

match
'login'
=>
'session#new'
,
:as
=>
:login

match 'login' => 'session#new', :as => :login

对于程序根路由, rails2:

map.root:controller=>
'users'
,:action=>
'index'

map.root :controller => 'users', :action => 'index'

rails3:

root
:to
=>
'users#index'

root :to => 'users#index'

对于遗留路由, rails2:

map.connect
':controller/:action/:id'
map.connect':controller/:action/:id.:format'

map.connect ':controller/:action/:id'
map.connect ':controller/:action/:id.:format'

那么在rails3中写法更优雅:

match
':controller(/:action(/:id(.:format)))'

match ':controller(/:action(/:id(.:format)))'

对于路由参数, rals2:

map.connect
'/articles/:year/:month/:day'
,
:controller
=>
'posts'
,
:action
=>
'index'

map.connect '/articles/:year/:month/:day', :controller => 'posts', :action => 'index'

rails3:

match
'/articles/:year/:month/:day'
=>
"posts#index"

match '/articles/:year/:month/:day' => "posts#index"

那么对于存档请求, 比如rails2:

map.connect
'/articles/:year/:month/:day'
,
:controller
=>
'posts'
,
:action
=>
'index'
map.connect'/articles/:year/:month'
,
:controller
=>
'posts'
,
:action
=>
'index'
map.connect'/articles/:year'
,
:controller
=>
'posts'
,
:action
=>
'index'

map.connect '/articles/:year/:month/:day', :controller => 'posts', :action => 'index'
map.connect '/articles/:year/:month', :controller => 'posts', :action => 'index'
map.connect '/articles/:year', :controller => 'posts', :action => 'index'

在rails3中:

match
'/articles(/:year(/:month(/:day)))'
=>
"posts#index"

match '/articles(/:year(/:month(/:day)))' => "posts#index"

指定请求方式, rails2:

map.connect
'/articles/:year'
,
:controller
=>
'posts'
,
:action
=>
'index'
,
:conditions
=>{
:method
=>
:get
}

map.connect '/articles/:year', :controller => 'posts', :action => 'index',
:conditions => {:method => :get}

在rails3中:

match
'/articles/:year'
=>
"posts#index"
,
:via
=>
:get
#或者更简单的:
get'/articles/:year'
=>
"posts#index"

match '/articles/:year' => "posts#index", :via => :get
#或者更简单的:
get '/articles/:year' => "posts#index"

对于跳转, rails3:

match
'signin'
,
:to
=>redirect(
"/login"
)
match'users/:name'
,
:to
=>redirect{|params|
"/#{params[:name]}"
}
match'google'
=>redirect(
'http://www.google.com/'
)

match 'signin', :to => redirect("/login")
match 'users/:name', :to => redirect {|params| "/#{params[:name]}" }
match 'google' => redirect('http://www.google.com/')

路由约束: rails2中实际上使用了 :requirements 符号

map.connect
'/:year'
,
:controller
=>
'posts'
,
:action
=>
'index'
,
:requirements
=>{
:year
=>//d{4}/}

map.connect '/:year', :controller => 'posts', :action => 'index',
                                    :requirements => { :year => //d{4}/ }

在rails3中:

match
'/:year'
=>
"posts#index"
,
:constraints
=>{
:year
=>//d{4}/}

match '/:year' => "posts#index", :constraints => {:year => //d{4}/}

:constraints
=>{
:user_agent
=>/iphone/}
:constraints
=>{
:ip
=>/192/.168/.1/./d{1,3}/}
constraints(:host
=>/localhost/)
do
resources:posts
end
constraintsIpRestrictordo
get'admin/accounts'
=>
"queenbee#accounts"
end

:constraints => { :user_agent => /iphone/ }
:constraints => { :ip => /192/.168/.1/./d{1,3}/ }
constraints(:host => /localhost/) do
    resources :posts
end
constraints IpRestrictor do
    get 'admin/accounts' => "queenbee#accounts"
end

对于Rack应用, rails3:

get
'hello'
=>proc{|env|[200,{},
"HelloRack"
]}

get'rack_endpoint'
=>PostsController.action(
:index
)

get'rack_app'
=>CustomRackApp

get 'hello' => proc { |env| [200, {}, "Hello Rack"] }

get 'rack_endpoint' => PostsController.action(:index)

get 'rack_app' => CustomRackApp

4. Bundler与ActionController

一个典型的rails应用, 我们一般需要在 environment.rb 指定你的 gems:

config.gem
"haml"
config.gem"chronic"
,
:version
=>
'0.2.3'

config.gem "haml"
config.gem "chronic", :version => '0.2.3'

然后我们运行 $ rake gems:install, 该命令会取得并下载然后安装编译这些gems到你的系统RubyGems目录中.

之后我们运行 $ rake gems:unpack:dependencise, 把这些gem打包到你应用程序的vendor/gems目录中去.

这样做产生的问题:

1. 它直接绑定到Rails中

2. 没有从本质上解决依赖问题

3. 运行时容易发生冲突

在rails3中, 使用了 bundle 命令:

直接在你的 gemfile 中指定你的 gem

gem
"haml"
gem"chronic"
,
'0.2.3'

gem "haml"
gem "chronic", '0.2.3'

然后运行 $ bundle, 该命令会会取得并下载然后安装编译这些gems

然后运行 $ bundle package 把gem源移到/vendor/cache中去.

这样rails应用中的gem与系统中的gem就不会相冲突.

一般的控制器语法:

class
UsersController<ApplicationController
def
index
@users
=User.all
respond_todo
|format|
format.html
format.xml{render:xml
=>
@users
.to_xml}
end
end

def
show
@user
=User.find(params[
:id
])
respond_todo
|format|
format.html#show.html.erb
format.xml{render:xml
=>
@user
}
end
end

...

class UsersController < ApplicationController
    def index
        @users = User.all
        respond_to do |format|
            format.html
            format.xml { render :xml => @users.to_xml } 
        end
    end

    def show
        @user = User.find(params[:id])
        respond_to do |format|
            format.html # show.html.erb
            format.xml { render :xml => @user }
        end
    end

...

改进的语法:

class
UsersController<ApplicationController
respond_to:html
,
:xml
,
:json
def
index
@users
=User.all
respond_with(@users
)
end
def
show
@user
=User.find(params[
:id
])
respond_with(@user
)
end
...

class UsersController < ApplicationController
    respond_to :html, :xml, :json
    def index
        @users = User.all
        respond_with(@users)
    end
    def show
        @user = User.find(params[:id])
        respond_with(@user)
    end
...

5. ActionMailer

rails2: $ script/generatemailerUserMailerwelcomeforgot_password

这将创建app/models/user_mailer.rb

那么在rails3中:$ railsgmailerUserMailerwelcomeforgot_password

这将创建app/mailers /user_mailer.rb

在实现部分, rails2:

def
welcome(user,subdomain)
subject'WelcometoTestApp'
recipientsuser.email
from'[e-mail]'
body:user
=>user,
:subdomain
=>subdomain
end

def welcome(user, subdomain)
    subject 'Welcome to TestApp'
    recipients user.email
    from '[e-mail]'
    body :user => user, :subdomain => subdomain
end

UserMailer.deliver_welcome(user,subdomain)

UserMailer.deliver_welcome(user, subdomain) 

在rails3中:

def
welcome(user,subdomain)
@user
=user
@subdomain
=subdomain
mail(:from
=>
"[e-mail]"
,
:to
=>user.email,
:subject
=>
"WelcometoTestApp"
)
end

def welcome(user, subdomain)
    @user = user
    @subdomain = subdomain
    mail(:from => "[e-mail]",
            :to => user.email,
            :subject => "Welcome to TestApp")
end

UserMailer.welcome(user,subdomain).deliver

UserMailer.welcome(user, subdomain).deliver

相比rails2, 我们在rails3下实现一个mail要简单的多:

class
UserMailer<ActionMailer::Base
default:from
=>
"[e-mail]"
,
:reply_to
=>
"[e-mail]"
,
"X-Time-Code"
=>
Time
.now.to_i.to_s
def
welcome(user,subdomain)
@user
=user
@subdomain
=subdomain
attachments['test.pdf'
]=
File
.read(
"#{Rails.root}/public/test.pdf"
)
mail(:to
=>
@user
.email,
:subject
=>
"WelcometoTestApp"
)
do
|format|
format.html{render'other_html_welcome'
}
format.text{render'other_text_welcome'
}
end
end
end

class UserMailer < ActionMailer::Base
    default :from => "[e-mail]",
                :reply_to => "[e-mail]",
                "X-Time-Code" => Time.now.to_i.to_s
    def welcome(user, subdomain)
        @user = user
        @subdomain = subdomain
        attachments['test.pdf'] = File.read("#{Rails.root}/public/test.pdf")
        mail(:to => @user.email, :subject => "Welcome to TestApp") do |format|
            format.html { render 'other_html_welcome' }
            format.text { render 'other_text_welcome' }
        end
    end
end

6. ActiveRelation 以及 ActiveModel

在rails2中, 我们经常使用下面的方法来进行查询:

@posts
=Post.find(
:all
,
:conditions
=>{
:published
=>
true
})

@posts = Post.find(:all, :conditions => {:published => true})

该方式将立即查询数据库然后返回Posts数组

而在rails3中:

@posts
=Post.where(
:published
=>
true
)

@posts = Post.where(:published => true)

该方法不会查询数据库, 仅仅返回一个 ActiveRecord::Relation 对象, 然后:

@posts
=Post.where(
:published
=>
true
)
if
params[
:order
]
@posts
=
@posts
.order(params[
:order
])
end
@posts
.
each

do
|p|
...#在这里进行查询,实现延迟加载
end

@posts = Post.where(:published => true)
if params[:order]
    @posts = @posts.order(params[:order])
end
@posts.each do |p|
    ...                 #在这里进行查询, 实现延迟加载
end

对于命名范围, 在rails2中:

class
Post<ActiveRecord::Base
default_scope:order
=>
'title'
named_scope:published
,
:conditions
=>{
:published
=>
true
}
named_scope:unpublished
,
:conditions
=>{
:published
=>
false
}
end

class Post < ActiveRecord::Base
    default_scope :order => 'title'
    named_scope :published, :conditions => {:published => true}
    named_scope :unpublished, :conditions => {:published => false}
end

而在rails3中:

class
Post<ActiveRecord::Base
default_scopeorder('title'
)
scope:published
,where(
:published
=>
true
)
scope:unpublished
,where(
:published
=>
false
)
end

class Post < ActiveRecord::Base
    default_scope order('title')
    scope :published, where(:published => true)
    scope :unpublished, where(:published => false)
end

对于查找方法, rails2:

Post.find(
:all
,
:conditions
=>{
:author
=>
"Joe"
},
:includes
=>
:comments
,
:order
=>
"title"
,
:limit
=>10)
 

在rails3:

Post.find(:all, :conditions => {:author => "Joe"}, :includes => :comments, :order => "title", :limit => 10)

Post.where(
:author
=>
"Joe"
).include(
:comments
).order(
:title
).limit(10).<strong><spanstyle=
"font-size:medium;"
>all</span></strong>

Post.where(:author => "Joe").include(:comments).order(:title).limit(10).all

7. 跨站点脚本(XSS)

在rails2中, 一般我们输入一段文本的时候, 我们往往会这样写: <%= h @post.body %>

那么在rails3中, <%= @post.body %> 默认输出的是一段safe html, 如果想输出XSS, 可以在前面加上 raw