agile rails

rest:
http://buddylindsey.com/kiss-dry-restful-crud-ruby-on-rails-links/

link_to "Goodbye", say_goodbye_path

say_googbye_path的意思是:/say/goodbye

rails请求流程:


agile rails

创建一个项目:

rails new depot

rails generate scaffold Product title:string description:text image_url:string price:decimal

%{}中间可以放字符串不用写双引号。

rake db:seed

Product.delete_all
# . . .
Product.create(title: 'Programming Ruby 1.9',
  description:
    %{<p>
    Ruby is the fastest growing and most exciting dynamic language
    out there. If you need to get working programs delivered fast,
    you should add Ruby to your toolbox.
    </p>},
  image_url: 'ruby.jpg',
  price: 49.95)
# . . .


application.html.erb加载所有css文件什么的。

如果想区分body样式可以:

<body class='<%= controller.controller_name %>'>

修改index页面:

<h1>
    Listing products
</h1>
<table>
    <% @products.each do |product| %>
        <tr class="<%= cycle('list_line_odd', 'list_line_even') %>">
            <td>
                <%=image_tag(product.image_url, class: 'list_image') %>
            </td>
            <td class="list_description">
                <dl>
                    <dt>
                        <%=product.title %>
                    </dt>
                    <dd>
                        <%=truncate(strip_tags(product.description), length: 80) %>
                    </dd>
                </dl>
            </td>
            <td class="list_actions">
                <%=link_to 'Show', product %>
                    <br/>
                    <%=link_to 'Edit', edit_product_path(product) %>
                        <br/>
                        <%=link_to 'Destroy', product, confirm: 'Are you sure?', method: :delete
                        %>
            </td>
        </tr>
        <% end %>
</table>
<br />
<%=link_to 'New product', new_product_path %>


1、cycle会把css class替换成list_line_even list_line_odd 的样子

2、truncate显示前80个字符,strip_tags去除html tags

3、confirm 弹出确认框

rake db:rollback 回滚

设置git:

git config --global --add user.name = "jerry"

git config --global --add user.email = [email protected]

git init

git add .

git commit -m "some message"

验证:

validates :title, :description, :image_url, presence: true

presence: true的意思是检查每个属性都被发送过来并且值不为空。

validates :price, numericality: {greater_than_or_equal_to: 0.01}

价格要大于等于0.01.为什么不是0,因为小数点后两位,如果输入0.001那么还是0

validates :title, uniqueness: true

名称不能重复:首先会检查table里面是不是有跟这个名称一样的字段

validates :image_url, allow_blank: true, format: {
  with: %r{\.(gif|jpg|png)$}i,
  message: 'must be a URL for GIF, JPG or PNG image.'
}

只测试是不是以jpg等后缀。


rake test 运行测试用例

root to: 'store#index', as: 'store'

as: 'store'告诉rails创建一个store_path变量。

<%= @page_title || "Pragmatic Bookshelf" %>

如果有这个参数就显示,没有的话就显示默认的。

application.css.scss 这个文件会包含所有stylesheet文件,在当前目录下或者自目录下。这个是由require_tree完成的。

helper:

<span class="price"><%= sprintf("$%0.02f", product.price) %></span>

下面使用内建的一个helper:number_to_currency

<span class="price"><%= number_to_currency(product.price) %></span>

rails使用session像hash,我们使用cart_id来索引cart

class ApplicationController < ActionController::Base
protect_from_forgery
 
  private
  
  def current_cart
    Cart.find(session[:cart_id])
    rescue ActiveRecord::RecordNotFound
    cart = Cart.create
    session[:cart_id] = cart.id
    cart
 end
end


Cart and line_items
class Cart < ActiveRecord::Base
  has_many :line_items, dependent: :destroy
end


destroy的意思就是当cart被删除的时候,line_items就没了

class Product < ActiveRecord::Base
  has_many :line_items
  before_destroy :ensure_not_referenced_by_any_line_item
#...
  private
  # ensure that there are no line items referencing this product
    def ensure_not_referenced_by_any_line_item
     if line_items.empty?
       return true
     else
       errors.add(:base, 'Line Items present')
       return false
     end
   end
end


当删除product的时候查看一下还有没有item里面指向他

<%= button_to 'Add to Cart', line_items_path(product_id: product) %>

这个意思是 这个product的product_id

form 应该是一个post请求,并且传递product_id: product参数

@cart = current_cart
product = Product.find(params[:product_id])
@line_item = @cart.line_items.build(product: product)

respond_to do |format|
  if @line_item.save
    format.html { redirect_to @line_item.cart,
    notice: 'Line item was successfully created.' }
    format.json { render json: @line_item,
    status: :created, location: @line_item }
  else
    format.html { render action: "new" }
    format.json { render json: @line_item.errors,
    status: :unprocessable_entity }
  end
end


@line_item = @cart.line_items.build(product: product)这段代码起到的作用是:

他会创建一个新的item将cart和product关联起来,你可以从任何一面创建连接。rails将会帮助你在两边建立起连接。


我们想跳转到cart界面而不是回到item界面,由于item可以找到cart,所以我们只需要把cart传递给方法即可。

在item里面添加货物数量的字段:

depot> rails generate migration add_quantity_to_line_items quantity:integer

rails可以匹配:add_XXX_to_TABLE and remove_XXX_from_TABLE

add_column :line_items, :quantity, :integer, default: 1

add product 代码:

def add_product(product_id)
current_item = line_items.find_by_product_id(product_id)
if current_item
  current_item.quantity += 1
else
  current_item = line_items.build(product_id: product_id)
end
current_item
end


删除:

➤ <%= button_to 'Empty cart', @cart, method: :delete,
➤ confirm: 'Are you sure?' %>

def destroy
    @cart = current_cart
    @cart.destroy
    session[:cart_id] = nil
    respond_to do |format|
      format.html { redirect_to store_url,
      notice: 'Your cart is currently empty' }
      format.json { head :no_content }
    end
end


product_url product_path path:product/1 url:http....product/1

<%= render(@cart.line_items) %>

render里面没写字符串怎么找partial?

默认去找当前目录下的_table 这里就是_line)item.html.erb

render path ??


➤ <%= button_to 'Add to Cart', line_items_path(product_id: product),
➤ remote: true %>

加一个remote: true就可以把这个变成一个ajax请求

告诉请求返回一个js:

respond_to do |format|
  if @line_item.save
    format.html { redirect_to store_url }
      format.js
      format.json { render json: @line_item,
        status: :created, location: @line_item }
  else
     format.html { render action: "new" }
       format.json { render json: @line_item.errors,
         status: :unprocessable_entity }
   end
end


创建一个line_item/create.js.erb

$('#cart').html("<%=j render @cart %>");


➤ $('#current_item').css({'background-color':'#88ff88'}).
➤ animate({'background-color':'#114411'}, 1000);

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