1_user.rb

class User < ApplicationRecord
  has_many :posts
  has_many :comments
  #  id                   :integer          not null, primary key
  #  name                 :string(50)       default("")
end

2_post.rb

class Post < ApplicationRecord
  belongs_to :user
  has_many :comments

  #  id                   :integer          not null, primary key
  #  user_id              :integer
  #  content              :text             default("")
  #  created_at           :datetime
end

3_comment.rb

class Comment < ApplicationRecord
  belongs_to :user
  belongs_to :post

  #  id                   :integer          not null, primary key
  #  user_id              :integer
  #  post_id              :integer
  #  content              :text             default("")
  #  created_at           :datetime
end

4_newsfeed_controller.rb

class NewsfeedController < ApplicationController
  # JSON endpoint that returns an array of Post objects in order of
  # newest first, to oldest last. Each Post contains a User object
  # (the author of the Post), and an array of Comments. Each Comment
  # will also include the User object of the Comment's author.
  
  # TODO: Newsfeed endpoint here
end

5_example.json

[
  {
    "type": "Post",
    "content": "First post",
    "user": {
      "type": "User",
      "name": "Luke"
    },
    "comments": [
      {
        "type": "Comment",
        "user": {
          "type": "User",
          "name": "Leia"
        },
        "content": "First comment"
      },
      {
        "type": "Comment",
        "user": {
          "type": "User",
          "name": "Han"
        },
        "content": "Second comment"
      },
    ]
  },
  {
    "type": "Post",
    "content": "Second post",
    "user": {
      "type": "User",
      "name": "Darth Vader"
    },
    "comments": [
      {
        "type": "Comment",
        "user": {
          "type": "User",
          "name": "Boba Fett"
        },
        "content": "Third comment"
      },
      {
        "type": "Comment",
        "user": {
          "type": "User",
          "name": "Jabba"
        },
        "content": "Fourth comment"
      },
    ]
  }
]

Reflektive has a newsfeed page - liken it to Facebook posts or LinkedIn Posts - where a User can create a message Post. Others can Comment on the post. The skeleton models are provided above.

The application will fetch posts from the newsfeed_controller. Presume that there are hundreds of posts per day. There may be a web app or mobile app or 3rd party consumer.

Build out the newsfeed_controller so that someone can fetch newsfeeds and produce the JSON above. You can presume that you only fetch 50 at a time.

Feel free to copy this gist and add your code to a gist. You do not have to have this be a running Rails app, but please use real code in your example (not pseudo code)

some thoughts: Can you make the queries efficient (what would this mean)? What if we want to reuse the query in other tasks? Would you organize the code in a different way? (e.g. Email the most recent 50 posts to somebody).