#73

backend/app/controllers/posts_controller.rb

@@ -5,16 +5,26 @@ require 'nokogiri'
 class PostsController < ApplicationController
   # GET /posts
   def index
-    latest_id = params[:latest].to_i
-    offset = params[:offset].to_i
+    limit = (params[:limit] || 20).to_i
+    cursor = params[:cursor]
 
-    posts = filtered_posts.order(created_at: :desc)
-    posts = if posts.first&.id == latest_id
-              posts.limit(20).offset(offset)
-            else
-              posts.limit(offset + 20)
-            end
-    render json: posts.as_json(include: { tags: { only: [:id, :name, :category, :post_count] } })
+    q = filtered_posts.order(created_at: :desc)
+
+    next_cursor = nil
+    if cursor.present?
+      q = q.where('posts.created_at < ?', Time.iso8601(cursor))
+    end
+
+    posts = q.limit(limit + 1)
+
+    next_cursor = nil
+    if posts.size > limit
+      next_cursor = posts.last.created_at.iso8601(6)
+      posts = posts.first(limit)
+    end
+
+    render json: { posts:       posts.as_json(include: { tags: { only: [:id, :name, :category, :post_count] } }),
+                   next_cursor: }
   end
 
   def random
@@ -31,7 +41,10 @@ class PostsController < ApplicationController
   # GET /posts/1
   def show
     post = Post.includes(:tags).find(params[:id])
-    viewed = current_user&.viewed?(post)
+    return head :not_found unless post
+
+    viewed = current_user&.viewed?(post) || false
+
     render json: (post
                   .as_json(include: { tags: { only: [:id, :name, :category] } })
                   .merge(viewed: viewed))
@@ -95,7 +108,7 @@ class PostsController < ApplicationController
   private
 
   def filtered_posts
-    tag_names = params[:tags]&.split(',')
+    tag_names = params[:tags]&.split(?\ )
     match_type = params[:match]
     tag_names.present? ? filter_posts_by_tags(tag_names, match_type) : Post.all
   end