ror：用户的微博

创建并切换分支

git checkout -b user-microposts

微博模型

基本模型

生成模型

rails generate model Micropost content:text user:references

修改迁移文件（添加索引）

# db/migrate/20170313121242_create_microposts.rb

class CreateMicroposts < ActiveRecord::Migration[5.0]
  def change
    create_table :microposts do |t|
      t.text :content
      t.references :user, foreign_key: true

      t.timestamps
    end
    add_index :microposts, [:user_id, :created_at]
  end
end

执行迁移

rails db:migrate

数据验证

# app/models/micropost.rb

class Micropost < ApplicationRecord
  belongs_to :user
  validates :user_id, presence: true
  validates :content, presence: true, length: { maximum: 140 }
end

添加测试

# test/models/micropost_test.rb

... ...
  def setup
    @user = users(:joshua)
    @micropost = Micropost.new(content: "Lorem ipsum", user_id: @user.id)
  end

  test "should be valid" do
    assert @micropost.valid?
  end
  
  test "user id should be present" do
    @micropost.user_id = nil
    assert_not @micropost.valid?
  end

  test "content should be present" do
    @micropost.content = " "
    assert_not @micropost.valid?
  end

  test "content should be at most 140 characters" do
    @micropost.content = "a" * 141
    assert_not @micropost.valid?
  end
... ...

执行测试

rails test:models

用户和微博关联

# app/models/user.rb

... ...
  has_many :microposts
... ...

修改测试

# test/models/micropost_test.rb

... ...
  def setup
    @user = users(:joshua)
    @micropost = @user.microposts.build(content: "Lorem ipsum")
  end
... ...

改进微博模型（排序）

添加固件

# test/fixtures/microposts.yml

orange:
  content: "I just ate an orange!"
  created_at: <%= 10.minutes.ago %>

tau_manifesto:
  content: "Check out the @tauday site by @mhartl: http://tauday.com"
  created_at: <%= 3.years.ago %>

cat_video:
  content: "Sad cats are sad: http://youtu.be/PKffm2uI4dk"
  created_at: <%= 2.hours.ago %>
  
most_recent:
  content: "Writing a short test"
  created_at: <%= Time.zone.now %>

添加测试

# test/models/micropost_test.rb

... ...
  test "order should be most recent first" do
    assert_equal Micropost.first, microposts(:most_recent)
  end
... ...

微博排序

# app/models/micropost.rb

class Micropost < ApplicationRecord
  belongs_to :user
  default_scope -> { order(created_at: :desc) }
... ...

执行测试

rails test:models

改进微博模型（依属关系）

# app/models/user.rb

... ...
  has_many :microposts, dependent: :destroy
... ...

编写测试

# test/models/user_test.rb

... ...
  test "associated microposts should be destroyed" do
    @user.save
    @user.microposts.create!(content: "Lorem ipsum")
    assert_difference 'Micropost.count', -1 do
      @user.destroy
    end
  end
... ...

显示微博

渲染微博

生成控制器

rails generate controller Microposts

局部视图

# app/views/microposts/micropost.html.erb


    <%= link_to gravatar_for(micropost.user, size: 50), micropost.user %>
    <%= link_to micropost.user.name, micropost.user %>
    <%= micropost.content %>
    
        Posted <%= time_ago_in_words(micropost.created_at) %> ago.

修改动作

# app/controllers/user_controller.rb

... ...
  def show
    @user = User.find(params[:id])
    @microposts = @user.microposts.paginate(page: params[:page])
  end
... ...

加入微博显示

# app/views/users/show.html.erb

... ...
    
        <% if @user.microposts.any? %>
            Microposts (<%= @user.microposts.count %>)
            
                <%= render @microposts %>
            
            <%= will_paginate @microposts %>
        <% end %>