標準的な Rails のアレ

post_controller.rb

# -*- coding: utf-8 -*-

class PostController < ApplicationController
  before_filter :require_post, only: [:show, :edit, :update, :destroy]

  def index
    @posts = posts
  end

  def new
    @post = posts.new
  end

  def create
    @post = posts.create(post_params)
    if @post.save
      redirect_to url_for(action: :show, id: @post.id), notice: '作成しました。'
    else
      render :new
    end
  end

  def edit
  end

  def update
    if @post.update_attributes(post_params)
      redirect_to url_for(action: :show, id: @post.id), notice: '更新しました。'
    else
      render :edit
    end
  end

  private

  def posts
    Post.where(user_id: current_user_id)
  end

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

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