Note: This post is intended as a supplement to WTF Just Happened? A Quick Tour of Your First Rails App.
MVC - Controller
As we have discussed in our article on REST and Rails, you will know that a Rails resource comes with seven standard methods for requesting data:
- show
- update
- destroy
- index
- create
- new
- edit
Consequently we will need seven methods in our controllers, one for each of them. Rails knows this and provides it for you automatically. Below is the controller code that you get from running rails generate scaffold Post. You will notice that the relevant HTTP verb that we introduced in REST and Rails is included as a comment before each method.
ruby
class PostsController < ApplicationController
before_action :set_post, only: [:show, :edit, :update, :destroy]
# GET /posts
# GET /posts.json
def index
@posts = Post.all
end
# GET /posts/1
# GET /posts/1.json
def show
end
# GET /posts/new
def new
@post = Post.new
end
# GET /posts/1/edit
def edit
end
# POST /posts
# POST /posts.json
def create
@post = Post.new(post_params)
respond_to do |format|
if @post.save
format.html { redirect_to @post, notice: 'Post was successfully created.' }
format.json { render :show, status: :created, location: @post }
else
format.html { render :new }
format.json { render json: @post.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /posts/1
# PATCH/PUT /posts/1.json
def update
respond_to do |format|
if @post.update(post_params)
format.html { redirect_to @post, notice: 'Post was successfully updated.' }
format.json { render :show, status: :ok, location: @post }
else
format.html { render :edit }
format.json { render json: @post.errors, status: :unprocessable_entity }
end
end
end
# DELETE /posts/1
# DELETE /posts/1.json
def destroy
@post.destroy
respond_to do |format|
format.html { redirect_to posts_url, notice: 'Post was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_post
@post = Post.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def post_params
params.require(:post).permit(:title, :body)
end
end