Agile Web Development With Rails 3rd - Product

 

创建项目,使用mysql数据库作为数据源

rails --database=mysql cart

 

设定Rails DB Environment

rake db:create RAILS_ENV="development"

 
运行Web服务器

ruby script/server

 

Product产品的制造

使用scaffold创建product(title,description,image_url)

ruby script/generate scaffold product title:string description:text image_url:string
rake db:migrate

 

添加migration(add_price_to_product)  添加price(decimal)字段

ruby script/generate migration add_price_to_product price:decimal
rake db:migrate

 

添加Product 测试数据

ruby script/generate migration add_test_data

 

class AddTestData < ActiveRecord::Migration
  def self.up
    Product.delete_all
    Product.create(
    :title => 'Progmatic Version Control', 
    :description =>
        %{<p>This book is a recipe-based approach to using Subversion that will get you up and running quickly</p>},
    :image_url => '/images/svn.jpg',
    :price => 28.50)
  end

  def self.down
    Product.delete_all
  end
end

 

 

为model(Product)添加Validaton

 

class Product < ActiveRecord::Base
  validates_presence_of :title, :description, :image_url
  validates_numericality_of :price
  validate  :price_must_be_at_least_a_cent
  validates_uniqueness_of :title
  validates_format_of :image_url, :with => %r{\.(gif|jpg|png)$}i, :message => "must be a URL for GIF/JPG/PNG"
  
  has_many  :line_items
  
  protected
  def price_must_be_at_least_a_cent
    errors.add(:price,"should be at least 0.01") if price.nil? || price < 0.01
  end
  
  def self.find_products_for_sale
    find(:all , :order => "title")
  end
  
end

 

 

rake db:migrate

 

用rake生成的ProductControl,包含index、show、new、edit、create、update等方法，基本的CRUD操作都已具备

class ProductsController < ApplicationController
  # GET /products
  # GET /products.xml
  def index
    @products = Product.all

    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @products }
    end
  end

  # GET /products/1
  # GET /products/1.xml
  def show
    @product = Product.find(params[:id])

    respond_to do |format|
      format.html # show.html.erb
      format.xml  { render :xml => @product }
    end
  end

  # GET /products/new
  # GET /products/new.xml
  def new
    @product = Product.new

    respond_to do |format|
      format.html # new.html.erb
      format.xml  { render :xml => @product }
    end
  end

  # GET /products/1/edit
  def edit
    @product = Product.find(params[:id])
  end

  # POST /products
  # POST /products.xml
  def create
    @product = Product.new(params[:product])

    respond_to do |format|
      if @product.save
        format.html { redirect_to(@product, :notice => 'Product was successfully created.') }
        format.xml  { render :xml => @product, :status => :created, :location => @product }
      else
        format.html { render :action => "new" }
        format.xml  { render :xml => @product.errors, :status => :unprocessable_entity }
      end
    end
  end

  # PUT /products/1
  # PUT /products/1.xml
  def update
    @product = Product.find(params[:id])

    respond_to do |format|
      if @product.update_attributes(params[:product])
        format.html { redirect_to(@product, :notice => 'Product was successfully updated.') }
        format.xml  { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml  { render :xml => @product.errors, :status => :unprocessable_entity }
      end
    end
  end

  # DELETE /products/1
  # DELETE /products/1.xml
  def destroy
    @product = Product.find(params[:id])
    @product.destroy

    respond_to do |format|
      format.html { redirect_to(products_url) }
      format.xml  { head :ok }
    end
  end
end

 

用于CRUD操作Product的页面也由rake动态生成，代码如下：

index.html.erb

<h1>Listing products</h1>

<table>
  <tr>
    <th>Title</th>
    <th>Description</th>
    <th>Image url</th>
  </tr>

<% @products.each do |product| %>
  <tr>
    <td><%=h product.title %></td>
    <td><%=h product.description %></td>
    <td><%=h product.image_url %></td>
    <td><%= link_to 'Show', product %></td>
    <td><%= link_to 'Edit', edit_product_path(product) %></td>
    <td><%= link_to 'Destroy', product, :confirm => 'Are you sure?', :method => :delete %></td>
  </tr>
<% end %>
</table>

<br />

<%= link_to 'New product', new_product_path %>

 

new.html.erb

<h1>New product</h1>

<% form_for(@product) do |f| %>
  <%= f.error_messages %>

  <p>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </p>
  <p>
    <%= f.label :description %><br />
    <%= f.text_area :description %>
  </p>
  <p>
    <%= f.label :image_url %><br />
    <%= f.text_field :image_url %>
  </p>
  <p>
    <%= f.submit 'Create' %>
  </p>
<% end %>

<%= link_to 'Back', products_path %>

 edit.html.erb

<h1>Editing product</h1>

<% form_for(@product) do |f| %>
  <%= f.error_messages %>

  <p>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </p>
  <p>
    <%= f.label :description %><br />
    <%= f.text_area :description %>
  </p>
  <p>
    <%= f.label :image_url %><br />
    <%= f.text_field :image_url %>
  </p>
  <p>
    <%= f.submit 'Update' %>
  </p>
<% end %>

<%= link_to 'Show', @product %> |
<%= link_to 'Back', products_path %>

 show.html.erb

<p>
  <b>Title:</b>
  <%=h @product.title %>
</p>

<p>
  <b>Description:</b>
  <%=h @product.description %>
</p>

<p>
  <b>Image url:</b>
  <%=h @product.image_url %>
</p>


<%= link_to 'Edit', edit_product_path(@product) %> |
<%= link_to 'Back', products_path %>