はじまりの大地

backend/app/controllers/application_controller.rb

@@ -0,0 +1,2 @@
+class ApplicationController < ActionController::API
+end

backend/app/controllers/posts_controller.rb

@@ -0,0 +1,51 @@
+class PostsController < ApplicationController
+  before_action :set_post, only: %i[ show update destroy ]
+
+  # GET /posts
+  def index
+    @posts = Post.all
+
+    render json: @posts
+  end
+
+  # GET /posts/1
+  def show
+    render json: @post
+  end
+
+  # POST /posts
+  def create
+    @post = Post.new(post_params)
+
+    if @post.save
+      render json: @post, status: :created, location: @post
+    else
+      render json: @post.errors, status: :unprocessable_entity
+    end
+  end
+
+  # PATCH/PUT /posts/1
+  def update
+    if @post.update(post_params)
+      render json: @post
+    else
+      render json: @post.errors, status: :unprocessable_entity
+    end
+  end
+
+  # DELETE /posts/1
+  def destroy
+    @post.destroy!
+  end
+
+  private
+    # Use callbacks to share common setup or constraints between actions.
+    def set_post
+      @post = Post.find(params.expect(:id))
+    end
+
+    # Only allow a list of trusted parameters through.
+    def post_params
+      params.expect(post: [ :title, :body ])
+    end
+end