两种方法实现收藏或者点赞功能

Posted on | In

收藏功能与点赞功能的实作十分类似，本文以购物车教程实作收藏功能为例。

方法一：

step1

一个用户可以收藏多个商品，一个商品可以被收藏很多次，因此这是多对多的关系。因此需要新增一个model，来当做product与suer的桥梁。$ rails g model collect user_id:integer product_id:integer,然后执行 rake db:migrate，然后为collect、user与product这三个model加上关联。

app/models/collect.rb
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   + belongs_to :user
   + belongs_to :product
```   

``` ruby app/models/product.rb

   + has_many :collects
   + has_many :collected_users, through: :collects, source: :user
app/models/user.rb
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   + has_many :collects
   + has_many :collected_products, through: :collects, source: :product

   #加上是否收藏商品的判定
   + def is_collect_of?(product)
   +  collected_products.include?(product)
   + end
```    

#### step2
首先修改路由信息：
``` ruby config/routes.rb

  + resources :product do
   +  member do
   +    post :collect
   +    post :uncollect
   + end
 +  end

在controller里加上对应的method，

app/controllers/product_controllers.rb
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+ def	collect
 + @product = Product.find(params[:id])
 + current_user.collected_products << @product
 + flash[:notice] = "成功收藏商品"
 + redirect_to :back
+ end

+ def uncollect
 + @product = Product.find(params[:id])
 + currrent_user.collected_products.delete(@product)
 + flash[:warning] = "您已取消收藏该商品"
 + redirect_to :back
+ end

step3

在views中的相应位置加入收藏的显示

app/views/products/show.html.erb
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+ <% if current_user && current_user.is_collect_of?(@product) %>
+  <%= link_to(“取消收藏”, uncollect_product_path(@product), :method => :post, class: "btn btn-danger btn-lg" )%>
+ <% else %>
+  <%= link_to("收藏“, collect_product_path(@product), :method => :post, class: "btn btn-danger btn-lg" )%>
+ <% end %>

方法二

step1

同样，终端执行 rails g model colloect, 编辑 db/migrate/XXXXXXXX_create_collects.rb

db/migrate/XXXXXXXX_create_collects.rb 
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  class CreateCollects < ActiveRecord::Migration[5.0]
    def change
      create_table :collects do |t|
+       t.integer :user_id, :index => true
+       t.integer :product_id, :index => true
        t.timestamps
      end
    end
  end

之后执行 rake db:migrate

编辑app/models/collect.rb,加上关联

app/models/collect.rb
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+ belongs_to :user
+ belongs_to :product

编辑 app/models/product.rb,加上关联

app/models/product.rb
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  + has_many :collects, :dependent => :destroy
  + had_many :collected_users, through: :collects, source: :user

  + def find_collect(user)
   +  self.collects.where( :user_id => user.id).first
  + end
```  

编辑 `app/model/user.rb`,加上关联
``` ruby app/models/user.rb
  +  has_many :collects, :dependent => :destroy
  +  has_many :collected_products, through: :collects,  source: :product

step2

编辑路由信息

config/routes.rb
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+ resource :products do
+   member do
+     post :collect
+     post :uncollect
+   end
+ end

在controller中添加：

app/controllers/product_controller.rb
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+ def collect
  + @product = Product.find(params[:id])    
  + unless @product.find_collect(cuurent_user)
  +   Collect.create( :user => current_user, :product => @product)
  + flash[:notice] = "您已成功收藏该商品"
  + end
  + redirect_to :back
+ end

+ def uncollect
   + @product = Product.find(params[:id])
   + collect = @product.find_collect(current_user)
   + collect.destroy
   + flash[:warning] = "您已取消收藏该商品"
   + redirect_to :back
+ end

Step3

最后一歩，就是要在 app/views/products/show.html.erb中加上收藏的按钮

app/views/products/show.html.erb
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……略
 + <% if current_user %>
 +   <% if @product.find_collect(current_user)%>
 +     <% =link_to("取消收藏", uncollect_product_path(@product), :method => :post, class: "btn btn-danger btn-lg")%>
 +   <% else %>
 +     <%= link_to("收藏", collect_product_path(@product), :method => :post, class: "btn btn-primary btn-lg")%>
 +   <% end %>
 + <% end %>
……略

成果展示