在Rails中显示用户的帖子列表

Question

I have a rails app where users post reviews of albums. The reviews that are posted are called "pins" and are uploaded with a release date, album title, artist name, album cover image, and rank for the year. (as in my #1 favorite album of the year) The pins belong users and the users have many pins. What I want to do is create a new page for 2013 that displays each user, then lists a descending ordered list of the album image, title, artist as their top ten list for the year. Something like:

<% @users.each do |user| %>
<%= link_to (image_tag user.image(:small)), user %> <%= user.name %>
<ol>   
  <li><%= @pin.album %> - <% @pin.artist%></li>     
    </ol>   
<% end %>

I need to limit the pins to only :date => "2013" and I need to list them in descending order.

I'm having trouble figuring out the controller and view. Here is my page controller so far:

def tens2013
  @users = User.all
  @pin = Pin.where(:date => "2013")
end

How should I set my controller to be able to call <%= @pin.user.album %> ?

Answer 1

1. To call @pin.user.album , you need to define the dependency first at the model level. So in the Pin model, you should have belongs_to :users and in the User model, you should include has_many :pins . Now this will assume that in the Pin model, there is a field called user_id , which will be the foreign key. Also use :include in the queries when you are going to access dependent classes like this. It avoids the N+1 query problem. eg:

    @pin = Pin.includes(:users).where("date >= ?","2013-01-01") 

2. To limit responses to only the year 2013, you may want to search your query likewise:

    @pin = Pin.where("date >= ?","2013-01-01") 

Answer 2

The way I see it, your models should be set up like this:

class User < ActiveRecord::Base
  has_many :pins
end

class Pin < ActiveRecord::Base
  belongs_to :user
  belongs_to :album
end

class Album < ActiveRecord::Base
  has_many :pins
end

Pin should have user_id and album_id to achieve this.

Then in the controller, you can eager load all users and their pins, with each pin's respective album, like this:

@users = User.includes(:pins => :album)

Or to limit to a certain year, do:

@users = User.includes(:pins => :album).where('pins.date>=?','2013-01-01').references(:pins)

Now you can iterate through the users in your view, and through each user's pins, and each pin's album.

You don't need to use @pin for each user's pin. Make the necessary changes in your view, and iterate through them using this style:

@users.each do |user|
  # do something 
  user.pins.each do |pin|
    # Now you have "pin" and you can use it:
    # pin.album...
    # pin.artist...
  end
end