四（上）、rails的控制器的CRUD

Step 0. git分支

$ git checkout -b ch03

Step 1. 增

app/controllers/groups_controller.rb

class GroupsController < ApplicationController
  def new
    @group = Group.new
  end
  
  def create
    @group = Group.new(group_params)
    @group.save

    redirect_to groups_path
  end

  private

  def group_params
    params.require(:group).permit(:title, :description)
  end
end

app/views/groups/new.html.erb

<div class="col-md-4 col-md-offset-4">
    <h2>新增讨论版</h2>

    <hr>
    <%= form_for @group do |f| %>

    标题
    <%= f.text_field :title %>
    <br>
    叙述
    <br>
    <%= f.text_area :description %>
    <br>

    <%= f.submit "Submit", :disable_with => 'Submitting...' %>
    <% end %>

</div>

Step 2. 查

app/controllers/groups_controller.rb

class GroupsController < ApplicationController
  def show
    @group = Group.find(params[:id])
  end
end

app/views/groups/show.html.erb

<div class="col-md-12">
  <div class="group">
    <%= link_to("Edit", edit_group_path(@group), class: "btn btn-primary pull-right")%>
  </div>
  <h2><%= @group.title %></h2>
  <p><%= @group.description %></p>
</div>

Step 3. 改

app/controllers/groups_controller.rb

class GroupsController < ApplicationController
  def edit
   @group = Group.find(params[:id])
  end
end

app/views/groups/edit.html.erb

<div class="col-md-4 col-md-offset-4">
    <h2>编辑讨论版</h2>

    <hr>
    <%= form_for @group do |f| %>

    标题
    <%= f.text_field :title %>
    <br>
    叙述
    <br>
    <%= f.text_area :description %>
    <br>

    <%= f.submit "Submit", :disable_with => 'Submiting...' %>
    <% end %>

</div>

app/controller/groups_controller.rb

class GroupsController < ApplicationController
   def update
     @group = Group.find(params[:id])
 
     @group.update(group_params)
 
     redirect_to groups_path, notice: "Update Success"
   end
end

Step 4. 删

app/controllers/groups_controller.rb

class GroupsController < ApplicationController
  def update
    @group = Group.find(params[:id])

    @group.update(group_params)

    redirect_to groups_path, notice: "Update Success"
  end
end

Step 5. git存档

$ git add .
$ git commit -m "implement groups#crud"