12.2 a web interface for following and followers.

1.before we do the UI, we need to populate database.

we will write a rake task to do this:

 

 

namespace :db do
  desc "populate database"
  task :populate => :environment do
    Rake:Task["db:reset"].invoke
    make_users
    make_microposts
    make_relationships
  end
end

def make_users
  admin = User.create!(:name => "fdf", :email => "[e-mail]", :pass...)
  admin.toggle!(:admin)
  # add 99 sample users
end

def make _microposts
  User.all(:limit => 6).each do |u|
    50.times do
      content = ......
      u.microposts.create!(:content => content)
    end
  end
end

def make_relationships
  users = User.all
  user = users.first
  following = users[1..50]
  followers = users[3..40]
  following.each { |followed| user.follow!(followed) }
  followers.each { |follower| follower.follow!(user)}
end

 

 

2. next, we will do the partial showing the following and followers number of a user.

 

since the two numbers are links, the following number will link to the following user list page.

 

the followers number link will link to the follower list, so we first prepare the url for the two pages.

 

both the page belong to :users  resources.

 

here is how we define the REST route:

 

resources :users do
  member do
    get :following, followers
  end
end

this part of code will create ulr like this:

 

users/1/following
users/1/followers

and the following named routes:

following_user_path(1)
followers_user_path(1)

to make the url work, we still need to define

def following

render 'show_follow'

end

def followers

render 'show_follow'

end

in users controller. 

 

and of course, the show_follow.html.erb should be in app/views/users

 

 

 

another kind of resoures routes is called collection:

 

resources :users do
  collection do
    get :tigers
  end
end

 this will create url:

 

users/tigers

tigers_users_path

 

3. after preparing routes, we will write test for the partial, since it will appear on user profile page and home page, so we will take this chance to refactor the test code in home page controller test, taking into account user signing in.

 

    describe "when signed in" do
      before :each do
        @user = test_sign_in(Factory(:user))
        other_user = Factory(:user, :email => Factory.next(:email))
        other_user.follow! @user
      end
      it "should have the right following and followers count" do
        get :home
        response.should have_selector('a', :href => following_user_path(@user), :content => "0 following")
        response.should have_selector('a', :href => followers_user_path(@user), :content => "1 follower")
      end
    end

 4. next we will do the stats partial:

 

<% @user ||= current_user %>
<div class="stats">
	<table summary="User stats">
		<tr>
			<td>
				<a href="<%= following_user_path(@user) %>">
					<span id="following" class="stats">
						<%= @user.following.count %> following
					</span>
				</a>
			</td>
			<td>
				<a href="<%= followers_user_path(@user) %>">
					<span id="followers" class="stats">
						<%= pluralize(@user.followers.count, "follower") %>
					</span>
				</a>
			</td>	
		</tr>
	</table>
</div>

 

pay special attention to the css id attr, it will be used for ajax, which access elements using their unique ids.

 

5. next, we can include the partial into the home page:

 

<% if signed_in? %>
        .
        .
        .
        <%= render 'shared/user_info' %>
        <%= render 'shared/stats' %>
      </td>
    </tr>
  </table>
<% else %>
  .
  .
  .
<% end %>

 

6. next, we will prepare the follow/unfollow form button partial:

 

<% unless current_user?(@user) %>
	<div id="follow_form">
		<% if current_user.following?(@user) %>
			<%= render 'unfollow' %>
		<% else %>
			<%= render 'follow' %>
		<% end %>
	</div>
<% end %>

 

7. next, we will prepare the routes for relationship resource:

 

resources :relationships, :only => [:create, :destroy]

 8. ok now we can do the follow/unfollow partial.

<%= form_for current_user.relationships.build(:followed_id => @user.id) do |f| %>
	<div><%= f.hidden_field :followed_id %></div>
	<div class="actions"><%= submit_tag 'follow' %></div>
<% end %>

 note, in the follow partial:

a. we new a relationship object, pass it as the param of form_for.

b. in this form, we only have a follow button.

c. but when user click this button, we need to make sure the form data include a param of 

relationship[followed_id], 

so we have to add a hidden field.

you may wondering, why I didn't input value into the hidden field, but it has data of user.id?

because of the build method, you already assign value to :followed_id, so the hidden field already has value of @user.id.

 

then is the unfollow partial:

<%= form_for current_user.relationships.find_by_followed_id(@user),
             :html => { :method => :delete } do |f| %>
  <div class="actions"><%= f.submit "Unfollow" %></div>
<% end %>

 

note, we don't need to hidden field here, since we only need the id to delete a object.

 

next we can put the stats partial and follow/unfollow partials into profile pages.

 

9. next, we will make following page and followers page.

first, we will make the link to following and followers page work, so first write test:

describe UsersController do
  .
  .
  .
  describe "follow pages" do

    describe "when not signed in" do

      it "should protect 'following'" do
        get :following, :id => 1
        response.should redirect_to(signin_path)
      end

      it "should protect 'followers'" do
        get :followers, :id => 1
        response.should redirect_to(signin_path)
      end
    end

    describe "when signed in" do

      before(:each) do
        @user = test_sign_in(Factory(:user))
        @other_user = Factory(:user, :email => Factory.next(:email))
        @user.follow!(@other_user)
      end

      it "should show user following" do
        get :following, :id => @user
        response.should have_selector("a", :href => user_path(@other_user),
                                           :content => @other_user.name)
      end

      it "should show user followers" do
        get :followers, :id => @other_user
        response.should have_selector("a", :href => user_path(@user),
                                           :content => @user.name)
      end
    end
  end
end

 

next, we will write code to make the test pass.

we need to add two new actions to users controller.

def following
    @title = "Following"
    @user = User.find(params[:id])
    @users = @user.following.paginate(:page => params[:page])
    render 'show_follow'
  end

  def followers
    @title = "Followers"
    @user = User.find(params[:id])
    @users = @user.followers.paginate(:page => params[:page])
    render 'show_follow'
  end
  .

 next, we will do the show_follw view:

<table summary="Information about following/followers">
  <tr>
    <td class="main">
      <h1><%= @title %></h1>

      <% unless @users.empty? %>
        <ul class="users">
          <%= render @users %>
        </ul>
        <%= will_paginate @users %>
      <% end %>
    </td>
    <td class="sidebar round">
      <strong>Name</strong> <%= @user.name %><br />
      <strong>URL</strong> <%= link_to user_path(@user), @user %><br />
      <strong>Microposts</strong> <%= @user.microposts.count %>
      <%= render 'shared/stats' %>
      <% unless @users.empty? %>
        <% @users.each do |user| %>
          <%= link_to gravatar_for(user, :size => 30), user %>
        <% end %>
      <% end %>
    </td>
  </tr>
</table>

 another thing to note, in the users controller, for the before filter of :authenticate, 

we change from :only to :except.

  before_filter :authenticate, :except => [:show, :new, :create]

 

10. next, we will try to make follow and unfollow button work.

since follow is creating a relationship, and unfollow is destroying a relationship, so we just need to add

create and destroying methods to relationships controller. 

 

let's start from TDD!!!

require 'spec_helper'

describe RelationshipsController do
  
  describe "access control" do
    it "should require signin for create" do
      post :create
      response.should redirect_to(signin_path)
    end
    it "should require sign in for destroy" do
      delete :destroy, :id => 1
      response.should redirect_to(signin_path)
    end
  end
  
  describe "POST 'create'" do
    before :each do
      @user = test_sign_in(Factory(:user))
      @followed = Factory(:user, :email => Factory.next(:email))
    end
    it "should create a relationship" do
      lambda do
        post :create, :relationship => { :followed_id => @followed }
        response.should be_redirect
      end.should change(Relationship, :count).by(1)
    end
  end
  
  describe "DELETE 'destroy'" do
    before :each do
      @user = test_sign_in(Factory(:user))
      @followed = Factory(:user, :email => Factory.next(:email))
      @user.follow!(@followed)
      @relationship = @user.relationships.find_by_followed_id(@followed)
    end
    it "should destroy a relationship" do
      lambda do
        delete :destroy, :id => @relationship
        response.should be_redirect
      end.should change(Relationship, :count).by(-1)
    end
  end  
  
end

 now we can write create and destroy method to make this test pass:

class RelationshipsController < ApplicationController
  before_filter :authenticate

  def create
    @user = User.find(params[:relationship][:followed_id])
    current_user.follow!(@user)
    redirect_to @user
  end

  def destroy
    @user = Relationship.find(params[:id]).followed
    current_user.unfollow!(@user)
    redirect_to @user
  end
end