【Ruby初学者向け講習】Slow Blog のパフォーマンス改善

app/controllers/posts_controller.rb

@@ -4,7 +4,7 @@ class PostsController < ApplicationController
   def index
     @user = User.find(params[:user_id])
 
-    posts_scope = @user.posts.eager_load(:comments)
+    posts_scope = @user.posts.preload(:comments)
     posts_scope = posts_scope.published unless Current.user == @user
 
     # Filter by tag if specified
@@ -13,7 +13,7 @@ def index
     end
 
     @page = Page.new(params: params, relation: posts_scope)
-    @posts = posts_scope.order(created_at: :desc).limit(@page.per_page).offset(@page.offset)
+    @posts = posts_scope.order(created_at: :desc).limit(@page.per_page).offset(@page.offset).preload(:tags, comments: :user)
     @all_user_tags = Tag.joins(:posts).where(posts: { user: @user }).distinct
   end
 

app/controllers/searches_controller.rb

@@ -6,7 +6,7 @@ def index
 
     if @tag
       @page = Page.new(params: params, relation: @tag.posts.published)
-      @posts = @tag.posts.published.order(view_count: :desc).limit(5).offset(@page.offset)
+      @posts = @tag.posts.published.order(view_count: :desc).limit(5).offset(@page.offset).preload(comments: :user)
     else
       @page = Page.new(params: params, relation: Post.none)
       @posts = Post.none

app/controllers/welcome_controller.rb

@@ -3,7 +3,7 @@ class WelcomeController < ApplicationController
 
   def index
     @page = Page.new(params: params, relation: Post)
-    @posts = Post.published.order(view_count: :desc).limit(5).offset(@page.offset)
+    @posts = Post.published.order(view_count: :desc).limit(5).offset(@page.offset).preload(:tags, comments: :user)
     @popular_tags = Tag.joins(:posts)
                       .where(posts: { status: :published })
                       .group("tags.id")

app/views/posts/_post.html.erb

@@ -12,8 +12,8 @@
   <% else%>
     <p><%= simple_format(post.body) %></p>
   <% end%>
-  
-  <% if post.tags.any? %>
+
+  <% if post.tags.present? %>
     <div style="margin-top: 10px;">
       <% post.tags.each do |tag| %>
         <span style="background-color: #007bff; color: white; padding: 3px 8px; border-radius: 12px; font-size: 0.8em; margin-right: 5px; display: inline-block;"><%= tag.name %></span>

app/views/posts/index.html.erb

@@ -13,8 +13,8 @@
     <section>
       <label for="tag_filter">Filter by tag:</label>
       <%= form_with url: user_posts_path(@user), method: :get, local: true do |form| %>
-        <%= form.select :tag_id, 
-            options_from_collection_for_select(@all_user_tags, :id, :name, params[:tag_id]), 
+        <%= form.select :tag_id,
+            options_from_collection_for_select(@all_user_tags, :id, :name, params[:tag_id]),
             { prompt: "All posts" },
             { onchange: "this.form.submit();" } %>
       <% end %>
@@ -30,7 +30,7 @@
       <%= render partial: post, locals: { short: true } %>
       <footer>
         <details>
-          <summary>Comments (<%= post.comments.count %>)</summary>
+          <summary>Comments (<%= post.comments.size %>)</summary>
           <%= render post.comments %>
         </details>
       </footer>
@@ -39,5 +39,3 @@
 
   <%= render 'posts/paging', page: @page %>
 </div>
-
-

app/views/searches/index.html.erb

@@ -18,12 +18,12 @@
       <%= render partial: post, locals: { short: true } %>
       <footer>
         <details>
-          <summary>Comments (<%= post.comments.count %>)</summary>
+          <summary>Comments (<%= post.comments.size %>)</summary>
           <%= render post.comments %>
         </details>
       </footer>
     </article>
   <% end %>
 
   <%= render 'posts/paging', page: @page, additional_params: { tag: params[:tag] } %>
-</div>
+</div>

app/views/welcome/index.html.erb

@@ -20,7 +20,7 @@
       <%= render partial: post, locals: { short: true } %>
       <footer>
         <details>
-          <summary>Comments (<%= post.comments.count %>)</summary>
+          <summary>Comments (<%= post.comments.size %>)</summary>
           <%= render post.comments %>
         </details>
       </footer>