chapter-04.txt

# 練習作業 4 - User 可以加入、退出社團

### 作業目標

* user 可以在 group 頁面加入社團 / 退出社團
* user 必須要是這個社團的成員才能發表文章

### 本章練習主題

* has_many_belongs_to
* custom routes





~~~~~~~~~


class PostsController < ApplicationController

  before_action :find_group
  before_action :login_required, :only => [:new, :create, :edit,:update,:destroy]
  before_action :member_required, :only => [:new, :create ]
  

  def new
    @post = @group.posts.build
  end

  def create
    @post = @group.posts.new(post_params)
    @post.author = current_user

    if @post.save
      redirect_to group_path(@group)
    else
      render :new
    end
  end

  def edit
    @post = current_user.posts.find(params[:id])
  end

  def update
    @post = current_user.posts.find(params[:id])

    if @post.update(post_params)
      redirect_to group_path(@group)
    else
      render :edit
    end
  end

  def destroy
    @post = current_user.posts.find(params[:id])

    @post.destroy

    redirect_to group_path(@group)
  end

  private

  def post_params
    params.require(:post).permit(:content)
  end

  def find_group
    @group = Group.find(params[:group_id])
  end

  def member_required
    if !current_user.is_member_of?(@group)
      flash[:warning] = " You are not member of this group!"
      redirect_to group_path(@group)
    end
  end
end

~~~~~~~~~