#101 マイグレとコントローラ

backend/app/controllers/posts_controller.rb

@@ -8,8 +8,11 @@ class PostsController < ApplicationController
     limit = params[:limit].presence&.to_i
     cursor = params[:cursor].presence
 
-    q = filtered_posts.order(created_at: :desc)
-    q = q.where('posts.created_at < ?', Time.iso8601(cursor)) if cursor
+    created_at = ('COALESCE(posts.original_created_before - INTERVAL 1 SECOND,' +
+                  'posts.original_created_from,' +
+                  'posts.created_at)')
+    q = filtered_posts.order(Arel.sql("#{ created_at } DESC"))
+    q = q.where("#{ created_at } < ?", Time.iso8601(cursor)) if cursor
 
     posts = limit ? q.limit(limit + 1) : q
 
@@ -20,14 +23,14 @@ class PostsController < ApplicationController
     end
 
     render json: { posts: posts.map { |post|
-      post.as_json(include: { tags: { only: [:id, :name, :category, :post_count] } }).tap { |json|
+      post.as_json(include: { tags: { only: [:id, :name, :category, :post_count] } }).tap do |json|
         json['thumbnail'] =
             if post.thumbnail.attached?
               rails_storage_proxy_url(post.thumbnail, only_path: false)
             else
               nil
             end
-      }
+      end
     }, next_cursor: }
   end
 
@@ -39,7 +42,7 @@ class PostsController < ApplicationController
 
     render json: (post
                   .as_json(include: { tags: { only: [:id, :name, :category, :post_count] } })
-                  .merge(viewed: viewed))
+                  .merge(viewed:))
   end
 
   # GET /posts/1
@@ -60,7 +63,7 @@ class PostsController < ApplicationController
     return head :forbidden unless current_user.member?
 
     # TODO: URL が正規のものがチェック，不正ならエラー
-    # TODO: title、URL は必須にする．
+    # TODO: URL は必須にする（タイトルは省略可）．
     # TODO: サイトに応じて thumbnail_base 設定
     title = params[:title]
     url = params[:url]

backend/db/migrate/20250909075500_add_original_created_at_to_posts.rb

@@ -0,0 +1,6 @@
+class AddOriginalCreatedAtToPosts < ActiveRecord::Migration[8.0]
+  def change
+    add_column :posts, :original_created_from, :datetime, after: :created_at
+    add_column :posts, :original_created_before, :datetime, after: :original_created_from
+  end
+end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_07_29_210600) do
+ActiveRecord::Schema[8.0].define(version: 2025_09_09_075500) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -83,6 +83,8 @@ ActiveRecord::Schema[8.0].define(version: 2025_07_29_210600) do
     t.bigint "parent_id"
     t.bigint "uploaded_user_id"
     t.datetime "created_at", null: false
+    t.datetime "original_created_from"
+    t.datetime "original_created_before"
     t.datetime "updated_at", null: false
     t.index ["parent_id"], name: "index_posts_on_parent_id"
     t.index ["uploaded_user_id"], name: "index_posts_on_uploaded_user_id"