REST示例exercise-阿里云开发者社区

Rails为支持REST开发提供的3个工具：

1. map.resources

map.connect '', :controller=>'home', :action=>'welcome'

map.connect '/post/:id', :controller=>'post', :action=>'show'

map.connect '/weather/:year/:month/:date', :controller=>'weather', :action=>'archive'

但是用这种方式在使用指定路由方式的时候，会给Rails开发人员增加许多重复性的劳动：

在视图中会这么使用代码：

link_to 'Home', :controller=>'home', :action=>'welcome'

link_to 'Show Post', :controller=>'post', :action=>'show', :id=>@post

link_to 'Weather Last Christmas',

:controller=>'weather', :action=>'archive', :year=>'2006', :month=>'12', :date=>'25'

重复性就是出现在手动指定controller， action，以及类似id的这些参数上。那么采用下面的路由方式会带来很大的改观：

map.home '', :controller=>'home',:action=>'welcome'

map.post '/post/:id', :controller=>'post', :action=>'show'

map.weather_archive '/weather/:yaer/:month/:date', :controller=>'weather', :action=>'archive'

这样创建了路由之后，Rails会自动提供两个新的URL方法：{named_route}_path和{named_route}.url例如map.home路由相应的这两个方法即为home_path和home_url, 开发人员可以通过这两个方法来生成指定路由的URL。二者的区别是：home_url方法生成的是绝对路径，包括主机地址和请求地址（例如[url]http://localhost:3000/[/url]）而home_path生成的是相对路径(/welcome)，因此，使用命名路由后，之前的rhtml里可以写做：

link_to 'Home', home_path

link_to 'Show Post', post_path(@post)

link_to 'Weather Last Christmas', weather_archive_path('2006', '12', '25')

虽然命名路由功能非常强大，但是对于REST开发来说还是显得力不从心，加入每个资源都拥有7个CRUD方法的话，就不得不创建大量的命名路由，不过rails提供了一个新的路由方法：map.resources, 创建REST方式的路由时，它可以提供类似于脚手架(scaffolding)的功能。举例来说：

map.resources :exercises

Rails会根据控制器中的方法自动创建所有对应的路由，以及相应生成的URL方法：

7个CRUD方法：

	Action	HTTP method	URL	生成URL的方法
1	index	GET	/exercises	exercises_path
2	show	GET	/exercises/1	exercises(:id)
3	new	GET	/exercises/new	new_exercise_path
4	edit	GET	/exercises/1;edit	edit_exercise_path(:id)
5	create	POST	/exercises	exercises_path
6	update	PUT	/exercises/1	exercises_path
7	destroy	DELETE	/exercises/1	exercises_path(:id)

2. respond_to

在非REST应用中，我们看到的方法可能如下：

def index

@exercises = Exercise.find(:all)

end

默认情况下，这个方法会自动显示相应的index模板文件（index.rhtml），但是如果改为使用REST，就能够以多种形式表现来自同一资源的数据，为了实现这点，在index方法中添加respond_to方法的调用：

def index

@exercises = Exercise.find(:all)

respond_to do |format|

format.html

format.xml {render :xml => @exercises.to_xml}

end

添加的respond_to 方法，会根据HTTP请求的头信息来返回相应的模板。因此如果用户发送普通的web请求，server返回HTML格式信息，如果是XML请求，server会以XML格式返回exercises对象。

3. scaffold_resource

scaffold_resource的脚手架的语法规则：

script/generate scaffold_resource ModelName [field:type ]…

--------------------------------------------

创建Exercise_app

1. rails exercise

2. .script/generate scaffold_resource exercise name:string user_id:integer

#用scaffold_resource创建了exercise类及其字段之后，rails会自动在route.rb中添加map.resources :exercises代码，并且会生成相应的migration.在index方法中， respond_to会根据头信息中的请求方式来确定返回的内容，Accept: text/html返回html形式的内容， Accept: text/xml返回xml形式的内容，但是如果发出/exercises.xml的GET请求，即使头信息为Accept: text/html也会返回xml模板，这样可以解决RSS的问题（RSS会发出类似/exercises.xml的GET请求，但是头信息为Accept:text/html）。

---------------------------------------------

使用restful_authentication插件，下载插件拷贝到vender/plugins目录下.

关于restful_authentication插件的详细说明，见里面的readme

---

3..script/generate authenticated user sessions

第一个参数指定了在注册时创建的模型对象（user或者account），在创建模型的同时，还会创建一个基本的，包含create方法的控制器

第二个参数指定了session会话控制器名称。该控制器用来处理站点中的登录和注销功能。

4. 配置路由config/route.rb

ActionController::Routing::Routes.draw do |map|
map.resources :exercises

map.home '', :controller=>'sessions', :action=>'new' #默认首页路由（删除public下的index.html文件）， [url]http://localhost:3000/[/url]
map.resources :users, :sessions
map.signup '/signup', :controller=>'users', :action=>'new'

map.login '/login', :controller=>'sessions', :action=>'new'
map.logout '/logout', :controller=>'sessions', :action=>'destory'

end

5. 将users_controller，sessions_controller中的"include AuthenticatedSystem"代码剪切到application_controller中，如果想支持"自动登录"功能，需要在application_controller中添加before_filter :login_from_cookie

6.将sessions视图下的new.rhtml文件第一行代码session_path改成sessions_path，此时打开 [url]http://localhost:3000/[/url] 就会出现默认首页（登录页面）

7.在layout目录下，删除由scaffold_resource生成的模板文件，新建application.rhtml来改变一下外观，代码：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
" [url]http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd[/url]">
<html>
<head>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8">
    <title><%=@title || "Exercisr"%></title>
    <link rel="stylesheet" type="text/css" href=" [url]http://yui.yahooapis.com/2.2.2/build/reset-fonts-grids/reset-fonts-grids.css[/url]">
    <%= stylesheet_link_tag 'styles' %>
    <%= javascript_include_tag :defaults %>
</head>
<body>
    <div id="doc2" class="yui-t2">
      <div id="hd" class="box grad blue">
        <%= image_tag 'grad_black.png'%>
        <h1 id="masthead"><%= link_to "Exercisr", home_path%></h1>
      </div>
      <div id="bd">
        <div id="yui-main">
          <div class="yui-b">
            <%= yield%>
          </div>
        </div>
        <%if logged_in?%>
          <div class="yui-b sidebar">
            <ul>
              <li><%=link_to 'Exercises', exercises_path%></li>
              <li><%# link_to 'Workouts', workouts_path%></li>
              <li><%# link_to 'Goals', goals_path%></li>
              <li><%# link_to 'Logout', logout_path%></li>
            </ul>
          </div>

<%else%>
            <div class="yui-b sidebar">
            <ul>
              <li><%= link_to 'signup', signup_path%></li>
            </ul>
          </div>

        <%end%>
      </div>
      <div id="ft" class="box grad blue"><%= image_tag 'grad_white.png'%></div>
    </div>
</body>
</html>

------下面的步骤用来设计页面导航

在sessions_controller中实现了3个方法中的2个-- create和destory，并且在这两个方法中都调用了redirect_back_or_default方法，现在redirect_back_or_default方法按照默认方式返回登录页面（即使已经登录），而我们现在需要让其返回到本系统的首页。

应该创建一个漂亮的，具有交互性的首页，能够为用户提供演示数据、教程等内容。但是现在我们创建一个静态页面，显示一些欢迎信息即可。同时在session模板中添加相应的模板代码。

8.在session_controller中添加一个welcome的action

def welcome

end

在welcome.rhtml模板中添加：

<h1>Welcome to Exercisr</h1>
<h3>A RESTful place to keep track of your workouts</h3>

之后在/config/routes.rb中添加一个新的命名路由（注意路由顺序）：

ActionController::Routing::Routes.draw do |map|
map.resources :exercises

map.home '', :controller=>'sessions', :action=>'new'
map.resources :users, :sessions
map.welcome '/welcome', :controller=>'sessions', :action=>'welcome'
map.signup '/signup', :controller=>'users', :action=>'new'
map.login '/login', :controller=>'sessions', :action=>'new'
map.logout '/logout', :controller=>'sessions', :action=>'destory'

end

最后修改sessions_controller中默认的跳转页面，使得create方法跳转到新创建的welcome页面，destroy返回到登录页面

def create
...

redirect_back_or_default(welcome_path)
...

end

#############

def destroy
...
redirect_back_or_default(login_path)
end

当用户注册之后，也应该跳转到welcome页面，所以修改user_controller的create方法：

def create
redirect_back_or_default(welcome_path)
end

现在打开 [url]http://localhost:3000/signup[/url]注册一个新帐户，测试一下刚设计的功能。

-------------------

创建模型关联

Exercise类：

class Exercise < ActiveRecord::Base
belongs_to :user
validates_presence_of :name
validates_uniqueness_of :name, :scope=>:user_id #一个用户不能输入两个相同的运动名
end

User类：

class User < ActiveRecord::Base
# ...
has_many :exercises, :dependent => :destroy, :order=>'name asc'

#...
end

修改Exercise控制器的作用域

之前对每个资源都生成了基本的CRUD操作，这些代码处于全局(Global)作用域中。需要降低代码的作用域。意思是:

譬如在对exercises生成的基本操作中，index这个action的代码是@exercises=Exercise.find(:all)，而现在需要的是在用户登录之后只寻找跟登录后的user相关联的exercises，也就是要将@exercises=Exercise.find(:all)写成@exercises=current_user.exercises.build.修改exercise_controller代码：

将其中的Exercise类的操作都换成current_user.exercises，将new方法换成build方法，具体代码如下：

class ExercisesController < ApplicationController
before_filter :login_required
# GET /exercises
# GET /exercises.xml
def index
@exercises =current_user.exercises.find(:all)

    respond_to do |format|
      format.html # index.rhtml
      format.xml { render :xml => @exercises.to_xml }
    end
end

# GET /exercises/1
# GET /exercises/1.xml
def show
@exercise =current_user.exercises.find(params[:id])

    respond_to do |format|
      format.html # show.rhtml
      format.xml { render :xml => @exercise.to_xml }
    end
end

# GET /exercises/new
def new
@exercise = current_user.exercises.build
end

# GET /exercises/1;edit
def edit
@exercise = current_user.exercises.find(params[:id])
end

# POST /exercises
# POST /exercises.xml
def create
@exercise = current_user.exercises.build(params[:exercise])

    respond_to do |format|
      if @exercise.save
        flash[:notice] = 'Exercise was successfully created.'
        format.html { redirect_to exercise_url(@exercise) }
        format.xml { head :created, :location => exercise_url(@exercise) }
      else
        format.html { render :action => "new" }
        format.xml { render :xml => @exercise.errors.to_xml }
      end
    end
end

# PUT /exercises/1
# PUT /exercises/1.xml
def update
@exercise = current_user.exercises.find(params[:id])

    respond_to do |format|
      if @exercise.update_attributes(params[:exercise])
        flash[:notice] = 'Exercise was successfully updated.'
        format.html { redirect_to exercise_url(@exercise) }
        format.xml { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml { render :xml => @exercise.errors.to_xml }
      end
    end
end

# DELETE /exercises/1
# DELETE /exercises/1.xml
def destroy
@exercise = current_user.exercises.find(params[:id])
@exercise.destroy

    respond_to do |format|
      format.html { redirect_to exercises_url }
      format.xml { head :ok }
    end
end
end

-------------

利用局部模板：

1.在创建或者修改exercise一项时，可以提取出来一个局部模板。在views/exercises下新建一个_form.rhtml文件，代码如下：

在new方法和edit视图中调用这个局部模板：

new.rhtml代码：

<h1>New exercise</h1>

<%= error_messages_for :exercise %>

<% form_for(:exercise, :url => exercises_path) do |f| %>
<%= render :partial=>"form", :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Back', exercises_path %>

edit.rhtml代码：

<h1>Editing exercise</h1>

<%= error_messages_for :exercise %>

<% form_for(:exercise, :url => exercise_path(@exercise), :html => { :method => :put }) do |f| %>
<%=render :partial=>'form', :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Show', exercise_path(@exercise) %> |
<%= link_to 'Back', exercises_path %>

把new模板的内容可以放到index页面中，直接可以在index中添加新的运动。修改后的index.rhtml:

<%# 介绍性的提示信息%>

<h1>Exercises</h1>
<p>On this page you can create and manage the exercises that you use in your workouts.</p>
<p>You can also view reports on your progress for each exercises</p>

<table id="exercise_details">
<tr>
<th>Name</th>
</tr>
<%= render :partial=>'exercise', :collection=>@exercises%>
</table>

<br /><br />
<h1>Add a New Exercise</h1>
<div id="add_exercise">
<% form_for(:exercise, :url=>exercises_path, :html=>{:id=>'new_exercise'}) do |f|%>
<%=render :partial=>'form', :locals=>{:f=>f}%>
<%end%>
</div>

---------

workout资源

用来记录用户在某一天锻炼的完成程度，该资源中，不仅应该包括进行锻炼的日期，还包括一个用来描述锻炼类型（上身、腹部或者双臂）的可选文本字段，具体实现过程：

1.ruby script/generate scaffold_resource workout date:date label:string user_id:integer

2.rake db:migrate

模型关系：

user.rb： has_many :workouts

workout.rb: belongs_to :user, :dependent => :destroy

修改控制器workout_controller作用域:

添加before_filter=>:login_required

修改7个方法中的@workout表达式,特别注意的是new和create中间对new方法的调用要改成build：

class WorkoutsController < ApplicationController
before_filter :login_required
# GET /workouts
# GET /workouts.xml
def index
@workouts = current_user.workouts.find(:all)

    respond_to do |format|
      format.html # index.rhtml
      format.xml { render :xml => @workouts.to_xml }
    end
end

# GET /workouts/1
# GET /workouts/1.xml
def show
@workout = current_user.workouts.find(params[:id])

    respond_to do |format|
      format.html # show.rhtml
      format.xml { render :xml => @workout.to_xml }
    end
end

# GET /workouts/new
def new
@workout = current_user.workouts.build
end

# GET /workouts/1;edit
def edit
@workout = current_user.workouts.find(params[:id])
end

# POST /workouts
# POST /workouts.xml
def create
@workout = current_user.workouts.build(params[:workout])

    respond_to do |format|
      if @workout.save
        flash[:notice] = 'Workout was successfully created.'
        format.html { redirect_to workout_url(@workout) }
        format.xml { head :created, :location => workout_url(@workout) }
      else
        format.html { render :action => "new" }
        format.xml { render :xml => @workout.errors.to_xml }
      end
    end
end

# PUT /workouts/1
# PUT /workouts/1.xml
def update
@workout = current_user.workouts.find(params[:id])

    respond_to do |format|
      if @workout.update_attributes(params[:workout])
        flash[:notice] = 'Workout was successfully updated.'
        format.html { redirect_to workout_url(@workout) }
        format.xml { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml { render :xml => @workout.errors.to_xml }
      end
    end
end

# DELETE /workouts/1
# DELETE /workouts/1.xml
def destroy
@workout = current_user.workouts.find(params[:id])
@workout.destroy

    respond_to do |format|
      format.html { redirect_to workouts_url }
      format.xml { head :ok }
    end
end
end

修改视图：

1.修改workout的index.rhtml页面：

<h1>Listing workouts</h1>

<table>
<tr>
<th>Date</th>
<th>Label</th>
</tr>
<%= render :partial=>'workout', :collection=>@workouts %>
</table>

<br />

<h1>Add a New Workout</h1>
<div id="add_workout">
<%form_for(:workout, :url=>workouts_path, :html=>{:id=>'new_workout'}) do |f|%>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<%end%>
</div>

2._workout.rhtml局部模板：

<td><%= link_to image_tag("display.gif", {:title=>"View Workout Details"}),workout_path(workout)%></td>
<td><%= link_to image_tag("edit_photo.gif", {:title=>"Edit Workout Date/label"}), edit_workout_path(workout) %></td>
<td><%= link_to image_tag("delete_photo.gif", {:title=>"Delete Workout"}), workout_path(workout), :confirm => 'Are you sure?', :method => :delete %></td>

</tr>

3.new.rhtml:

<h1>New workout</h1>

<%= error_messages_for :workout %>

<% form_for(:workout, :url => workouts_path) do |f| %>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Back', workouts_path %>

4.edit.rhtml

<h1>Editing workout</h1>

<%= error_messages_for :workout %>

<% form_for(:workout, :url => workout_path(@workout), :html => { :method => :put }) do |f| %>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Show', workout_path(@workout) %> |
<%= link_to 'Back', workouts_path %>

5._form.rhtml局部模板：

<p>
<b>Label</b><br />
<%= f.text_field :label %>
</p>

-----------------

记录锻炼过程中的数据：

在创建完每次的workout对象之后，需要记录如下信息：

1.本次锻炼进行了哪几项运动。(exercises)

2.每项运动完成了几组()

3.每次运动使用的重量或者负荷(resistance)

4.每组运动进行的次数(repitition)

按照这些需求，我们应该新建这样一张表，表中每一行必须表示一组运动，其中记录的数据包括：workoutID(外键，用来查询关联的workout)、exerciseID(外键，用来查询关联的exercise)、该组运动使用的重量以及该组包含的运动次数。

创建这个资源，名字叫做activities(活动).

过程：

1.ruby script/generate scaffold_resource activity workout_id:integer exercise_id:integer resistance:integer repetitions:integer

2.rake db:migrate

3.删除生成的layout文件

---4.创建模型之间的关系：

class Activity < ActiveRecord::Base
belongs_to :exercise
belongs_to :workout
validates_presence_of :resistance, :repetitions
end

class Workout < ActiveRecord::Base
belongs_to :user
has_many :activities, :dependent=>:destroy
has_many :exercises, :through=>:activities
validates_presence_of :date
end

class User < ActiveRecord::Base
# Virtual attribute for the unencrypted password
has_many :exercises, :dependent => :destroy, :order=>'name asc'
has_many :workouts, :dependent => :destroy
has_many :activities, :through=>:workouts

...

end

修改activity路由

ActionController::Routing::Routes.draw do |map|
# map.resources :activities

map.resources :workouts do |workout|
workout.resources :activities
end

...

这是一个嵌套式路由的写法，简单的来说，先要得到workouts的资源，然后根据workouts得到activities资源，如果不然没有意义。

修改activities_controller

跟以前一样，在activities_controller里首先要加上before_filter :login_required，确保只有用户登录之后访问控制器中的方法，其次，由于使用了嵌套路由，所以在限制查询范围方面需要进行一些修改。在之前的控制器中，我们将查询范围限定为当前用户，而现在对于嵌套资源来说，需要在父资源中进行查询。

所以还得首先得出父资源的实例变量值。所以定义一个protected方法，然后在控制器开始加上before_filter :find_workout

这个protected的find_workout方法写在activities_controller的最下面：

protected
def find_workout
@workout= current_user.workouts.find(params[:workout_id])
end

然后再在最上面写上before_filter :find_workout，这样就得到了实例变量@workout

在其他的方法中做出修改如下：

class ActivitiesController < ApplicationController
before_filter :login_required
before_filter :find_workout
# GET /activities
# GET /activities.xml
def index
    @activities = @workout.activities.find(:all)
    respond_to do |format|
      format.html # index.rhtml
      format.xml { render :xml => @activities.to_xml }
    end
end

# GET /activities/1
# GET /activities/1.xml
def show
@activity = @workout.activities.find(params[:id])

    respond_to do |format|
      format.html # show.rhtml
      format.xml { render :xml => @activity.to_xml }
    end
end

# GET /activities/new
def new
@activity = @workout.activities.build
end

# GET /activities/1;edit
def edit
@activity = @workout.activities.find(params[:id])
end

# POST /activities
# POST /activities.xml

def create
@activity = @workout.activities.build(params[:activity])

respond_to do |format|
    if @activity.save
      flash[:notice] = 'Activity was successfully created.'
       format.html { redirect_to workout_path(@workout) }
      format.xml { head :created, :location => activity_url(@workout,@activity) }
    else
      format.html { render :action => "new" }
      format.xml { render :xml => @activity.errors.to_xml }
    end
end
end

# PUT /activities/1
# PUT /activities/1.xml

def update
@activity = @workout.activities.find(params[:id])

   respond_to do |format|
     if @activity.update_attributes(params[:activity])
       flash[:notice] = 'Activity was successfully updated.'
       format.html { redirect_to workout_path(@workout) }
       format.xml { head :ok }
     else
       format.html { render :action => "edit" }
       format.xml { render :xml => @activity.errors.to_xml }
     end
   end
end

# DELETE /activities/1
# DELETE /activities/1.xml
def destroy
@activity = @workout.activities.find(params[:id])
@activity.destroy

    respond_to do |format|
      format.html { redirect_to activities_url }
      format.xml { head :ok }
    end
end

protected
def find_workout
@workout= current_user.workouts.find(params[:workout_id])
end

end

修改activity视图模板：

这里修改activity模板跟以前的类似，有一点就是因为activity资源必须是以workout资源为前提的，所以在参数传递时要加上@workout,下面首先来创建一个_activity.rhtml模板：

<td><%=h activity.resistance %></td>

<td><%=h activity.repetitions %></td>

<td><%= link_to image_tag("edit_photo.gif", {:title=>"Edit Exercise"}), edit_activity_path(@workout,activity) %></td>
<td><%= link_to image_tag("delete_photo.gif"), activity_path(@workout,activity), :confirm => 'Are you sure?', :method => :delete %></td>
</tr>

然后创建一个_form.rhtml模板：

<p>
<%= f.collection_select :exercise_id, current_user.exercises.find(:all), :id, :name, :prompt=>"Select an Exercise" %>
</p>

<p>One set of <%= f.text_field :repetitions %>with <%= f.text_field :resistance%>pounds of resistance.
</p>

修改edit.rhtml模板：

<h1>Editing activity</h1>

<%= error_messages_for :activity %>

<% form_for(:activity, :url => activity_path(@workout,@activity), :html => { :method => :put }) do |f| %>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Back', activities_path(@workout) %>

修改index视图模板：

<h1>Listing activities</h1>

<table>
<tr>
    <th>Exercise</th>
    <th>Resistance</th>
    <th>Repetitions</th>
</tr>

<%= render :partial=>'activity', :collection=>@activities%>

</table>

<br />

<%= link_to 'New activity', new_activity_path(@workout) %>

修改new.rhtml模板：

<h1>New activity</h1>

<%= error_messages_for :activity %>

<% form_for(:activity, :url => activities_path) do |f| %>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Back', activities_path(@workout) %>

最后，修改show.rhtml模板：

<p>
<b>Exercise:</b>
<%=h @activity.exercise %>
</p>

<p>
<b>Resistance:</b>
<%=h @activity.resistance %>
</p>

<p>
<b>Repetitions:</b>
<%=h @activity.repetitions %>
</p>

<%= link_to 'Edit', edit_activity_path(@workout,@activity) %> |
<%= link_to 'Back', activities_path(@workout) %>

修改workout控制器的show方法：

def show
    @workout = current_user.workouts.find(params[:id])
    @activities= @workout.activities.find(:all, :include=>:exercise)
    respond_to do |format|
      format.html # show.rhtml
      format.xml { render :xml => @workout.to_xml }
    end
end

修改workout/show.rhtml模板：

<h1><%= h @workout.label%>Workout on <%= h @workout.date.to_s(:long)%></h1>
<table>
<tr><th>Exercise</th><th>Reps</th><th>Resistance</th></tr>
<%=render :partial=>'activities/activity', :collection=>@activities%>
</table>

<h3>Add Exercise to this workout</h3>
<%form_for(:activity, :url=>activities_path(@workout)) do |f|%>
<%= render :partial=>'activities/form', :locals=>{:f=>f}%>
<%end%>
<%=link_to "Back", workouts_path%>

---改进添加Activity的表单

如果在选择运动时发现运动名称不在select表单中，后面需要加入一个文本框，用来添加运动名称：

先在activity的_form.rhtml模板中增加一个文本框，用来输入要添加的运动名称：

<p>
<%= f.collection_select :exercise_id, current_user.exercises.find(:all), :id, :name, :prompt=>"Select an Exercise" %>
or add a new exercise:
<%= f.text_field :new_exercise_name%>
</p>

<p>One set of <%= f.text_field :repetitions %>with <%= f.text_field :resistance%>pounds of resistance.
</p>

这里将文本框内容传递给了:new_exercise_name，在activity模型类中创建一个虚拟属性new_exercise_name

class Activity < ActiveRecord::Base
belongs_to :exercise
belongs_to :workout
validates_presence_of :resistance, :repetitions
attr_accessor :new_exercise_name

before_save :create_exercise_if_submitted
def create_exercise_if_submitted
create_exercise(:user_id=>workout.user_id,
:name=>new_exercise_name) unless new_exercise_name.blank?
end
end

--------跟踪锻炼目标：

下面创建一个资源，用来跟踪锻炼目标（体重、血糖等）。该资源属性包括要跟踪的目标名称，要达到的目标，以及该目标上次锻炼后的结果（以便计算当前与目标之间的差距），确定属性后，创建goal资源：

ruby script/generate scaffold_resource goal name:string value:decimal last:decimal user_id:integer

我们还需要记录在当前尚未实现目标时的数据。例如，加入用户的目标是跟踪自己的体重，那么可能希望每周都记录一下自己的体重，以便查看是否有变化，我们将这个资源命名为result，包含以下几个属性：该对象关联的目标（goal对象），本次记录的时间，以及记录的数据。

ruby script/generate scaffold_resource result goal_id:integer date:date value:decimal

rake db:migrate

删除生成的layout

---

修改模型类：

class Goal < ActiveRecord::Base
belongs_to :user
has_many :results, :dependent => :destroy
validates_presence_of :value
end

class Result < ActiveRecord::Base
belongs_to :goal
validates_presence_of :date, :value
end

class User < ActiveRecord::Base
...
has_many :goals

...

end

创建嵌套路由：

ActionController::Routing::Routes.draw do |map|
# map.resources :results

# map.resources :goals

#map.resources :activities

map.resources :goals do |goal|
goal.resources :results
end

...

配置控制器：

class GoalsController < ApplicationController
before_filter :login_required
# GET /goals
# GET /goals.xml
def index
@goals = current_user.goals.find(:all)

    respond_to do |format|
      format.html # index.rhtml
      format.xml { render :xml => @goals.to_xml }
    end
end

# GET /goals/1
# GET /goals/1.xml
def show
@goal = current_user.goals.find(params[:id])
@results=@goal.results.find(:all, :order=>'date desc')

    respond_to do |format|
      format.html # show.rhtml
      format.xml { render :xml => @goal.to_xml }
    end
end

# GET /goals/new
def new
@goal = current_user.goals.build
end

# GET /goals/1;edit
def edit
@goal = current_user.goals.find(params[:id])
end

# POST /goals
# POST /goals.xml
def create
@goal = current_user.goals.build(params[:goal])

    respond_to do |format|
      if @goal.save
        flash[:notice] = 'Goal was successfully created.'
        format.html { redirect_to goal_url(@goal) }
        format.xml { head :created, :location => goal_url(@goal) }
      else
        format.html { render :action => "new" }
        format.xml { render :xml => @goal.errors.to_xml }
      end
    end
end

# PUT /goals/1
# PUT /goals/1.xml
def update
@goal = current_user.goals.find(params[:id])

    respond_to do |format|
      if @goal.update_attributes(params[:goal])
        flash[:notice] = 'Goal was successfully updated.'
        format.html { redirect_to goal_url(@goal) }
        format.xml { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml { render :xml => @goal.errors.to_xml }
      end
    end
end

# DELETE /goals/1
# DELETE /goals/1.xml
def destroy
@goal = current_user.goals.find(params[:id])
@goal.destroy

    respond_to do |format|
      format.html { redirect_to goals_url }
      format.xml { head :ok }
    end
end
end

由于result是一个嵌套资源，所以对于Results控制器来说，需要按照前面修改activities控制器的方法来修改：

class ResultsController < ApplicationController
# GET /results
# GET /results.xml
before_filter :login_required
before_filter :find_goal
def index
@results = @goal.results.find(:all)

    respond_to do |format|
      format.html # index.rhtml
      format.xml { render :xml => @results.to_xml }
    end
end

# GET /results/1
# GET /results/1.xml
def show
@result = @goal.results.find(params[:id])

    respond_to do |format|
      format.html # show.rhtml
      format.xml { render :xml => @result.to_xml }
    end
end

# GET /results/new
def new
@result = @goal.results.build
end

# GET /results/1;edit
def edit
@result = @goal.results.find(params[:id])
end

# POST /results
# POST /results.xml
def create
@result = @goal.results.build(params[:result])

    respond_to do |format|
      if @result.save
        flash[:notice] = 'Result was successfully created.'
        format.html { redirect_to goal_url(@goal) }
        format.xml { head :created, :location => result_url(@result) }
      else
        format.html { render :action => "new" }
        format.xml { render :xml => @result.errors.to_xml }
      end
    end
end

# PUT /results/1
# PUT /results/1.xml
def update
@result = @goal.results.find(params[:id])

    respond_to do |format|
      if @result.update_attributes(params[:result])
        flash[:notice] = 'Result was successfully updated.'
        format.html { redirect_to goal_url(@goal) }
        format.xml { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml { render :xml => @result.errors.to_xml }
      end
    end
end

# DELETE /results/1
# DELETE /results/1.xml
def destroy
@result = @goal.results.find(params[:id])
@result.destroy

    respond_to do |format|
       format.html { redirect_to goal_url(@goal) }
      format.xml { head :ok }
    end
end
protected
def find_goal
    @goal=current_user.goals.find(params[:goal_id])
end
end

配置视图：

首先在layout/appliaction.rhtml中去掉<li><%# link_to 'Goals', goals_path%></li>中的#

1.goal视图：

这里的修改于之前的workout模板的修改基本一致。

新建_form.rhtml

<p>
<label for="goal-value">Goal to Reach:</label><br />
<%= f.text_field :value %>
</p>

<p>
<label for="goal-last">Current Result:</label><br />
<%= f.text_field :last %>
</p>

在edit和new中调用此局部模板：

edit.rhtml

<h1>Editing goal</h1>

<%= error_messages_for :goal %>

<% form_for(:goal, :url => goal_path(@goal), :html => { :method => :put }) do |f| %>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Show', goal_path(@goal) %> |
<%= link_to 'Back', goals_path %>

new.rhtml

<%= error_messages_for :goal %>

<% form_for(:goal, :url => goals_path) do |f| %>
<%= render :partial=>"form", :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Back', goals_path %>

新建_goal.rhtml模板：

    <td><%= link_to image_tag("display.gif", {:title=>'View Report'}), goal_path(goal) %></td>
    <td><%= link_to image_tag('edit_photo.gif',{:title=>"Edit Goal Details"}), edit_goal_path(goal) %></td>
    <td><%= link_to image_tag("delete_photo.gif"), goal_path(goal), :confirm => 'Are you sure?', :method => :delete %></td>
</tr>

最后在index页面(goals/index.rhtml)中添加显示两个局部模板的代码：

<h1>Listing goals</h1>

<table>
<tr>
<th>Name</th>
</tr>

<%=render :partial=>"goal", :collection=>@goals%>

</table>

<br />
<h1>Add a New Goal</h1>
<div id="add_goal">
<% form_for(:goal, :url=>goals_path, :html=>{:id=>'new_goal'}) do |f|%>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<%end%>
</div>

2.result视图

同样，我们首先创建两个局部模板文件，然后在视图模板中调用这两个局部模板。其次，由于result是一个嵌套资源，所以还需要向所有相关的命名路由传递@goals变量

_form.rhtml:

<p>
<label for="">Value</label><br />
<%= f.text_field :value %>
</p>

_result.rhtml

<td><%= link_to image_tag("edit_photo.gif", {:title=>"Edit Result Details"}), edit_result_path(@goal,result) %></td>
<td><%= link_to image_tag("delete_photo.gif",{:title=>"Delete Result"}), result_path(@goal,result), :confirm => 'Are you sure?', :method => :delete %></td>
</tr>

new.rhtml

<h1>New result</h1>

<%= error_messages_for :result %>

<% form_for(:result, :url => results_path(@goal)) do |f| %>
<%= render :partial=>'form', :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Back', results_path(@goal) %>

edit.rhtml

<h1>Editing result</h1>

<%= error_messages_for :result %>

<% form_for(:result, :url => result_path(@goal,@result), :html => { :method => :put }) do |f| %>
<%= render :partial=>"form", :locals=>{:f=>f}%>
<% end %>

<%= link_to 'Back to Goal', goal_path(@goal) %>

index.rhtml

<h1>Listing results for<%= h @goal.name%></h1>

<th>Date</th>
<th>Value</th>
</tr>

<%= render partial=> 'result', :collection=>@results%>

</table>

最后，修改goal资源的show模板：

<h1>Results for <%= h @goal.name%></h1>
<table>
<tr><th>Date</th><th>Value</th></tr>
<%= render :partial=>'results/result', :collection=>@results%>
</table>

<h3>Record New Result for this Goal</h3>
<% form_for :result, :url=>results_path(@goal) do |f|%>
<%= render :partial=>'results/form', :locals=>{:f=>f}%>
<%end%>
<%= link_to 'Back', workouts_path%>

按照前面的设计，还需要存储最近一次锻炼结果的数据。在这里要借助rails强大的回调函数，可以解决这个问题。打开models/results.rb添加after_create回调函数来设置相关goal资源的last属性。

class Result < ActiveRecord::Base
belongs_to :goal
validates_presence_of :date, :value
after_create :update_last_result
def update_last_result
goal.last=value
goal.save
end
end

本文转自 fsjoy1983 51CTO博客，原文链接：http://blog.51cto.com/fsjoy/99346，如需转载请自行联系原作者

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