undefined method error 'Public Activity Gem' - ruby-on-rails

Question

I have a simple rails app and i am trying to add an activity feed on it. For that i am using the Public Activity Gem and was following the this Railscast
but now it's giving me an error:
undefined method `shipment' for #<Shipment:0x6a96578>
My codes are:
activities_controller.rb
class ActivitiesController < ApplicationController
def index
#activities = PublicActivity::Activity.order("created_at desc")
end
end
My Activity index.html.erb file
<h1>feeds</h1>
<% #activities.each do |activity| %>
<div class="activity">
<%= link_to activity.owner.full_name, activity.owner if activity.owner %>
added comment to <%= link_to activity.trackable.shipment.name.activity.trackable.shipment %>
</div>
<% end %>
My comment.rb file
class Comment < ActiveRecord::Base
include PublicActivity::Model
tracked owner: ->(controller, model) { controller && controller.current_user }
belongs_to :shipment
belongs_to :user
end
I have a simple rails app and i am trying to add an activity feed on it. For that i am using the Public Activity Gem and was following the this Railscast
but now it's giving me an error:
undefined method `user_path' for #<#:0x4a90a30>
My codes are:
activities_controller.rb
class ActivitiesController < ApplicationController
def index
#activities = PublicActivity::Activity.order("created_at desc")
end
end
My Activity index.html.erb file
<h1>feeds</h1>
<% #activities.each do |activity| %>
<div class="activity">
<%= link_to activity.owner.full_name, activity.owner if activity.owner %>
added comment to <%= link_to activity.trackable.shipment.name.activity.trackable.shipment %>
</div>
<% end %>
My comment.rb file
class Comment < ActiveRecord::Base
include PublicActivity::Model
tracked owner: ->(controller, model) { controller && controller.current_user }
belongs_to :shipment
belongs_to :user
end
My routes.rb file
Rails.application.routes.draw do
get 'activities/index'
get 'profiles/show'
get 'pages/homepage'
devise_for :users, :controllers => {:registrations => "registrations"}
resources :shipments do
member do
get "like", to: "shipments#upvote"
end
resources :comments
end
# The priority is based upon order of creation: first created -> highest priority.
# See how all your routes lay out with "rake routes".
root "shipments#index"
get '/:id', to: 'profiles#show'
get "mailbox/inbox" => "mailbox#inbox", as: :mailbox_inbox
get "mailbox/sent" => "mailbox#sent", as: :mailbox_sent
get "mailbox/trash" => "mailbox#trash", as: :mailbox_trash
resources :conversations do
member do
post :reply
post :trash
post :untrash
resources :users
end
end
end
stack trace
Rendered activities/index.html.erb within layouts/application (31.2ms)
Completed 500 Internal Server Error in 109ms (ActiveRecord: 78.0ms)
ActionView::Template::Error (undefined method `shipment' for #<Shipment:0x4dc44b
0>):
2: <% #activities.each do |activity| %>
3: <div class="activity">
4: <%= link_to activity.owner.profile_name, activity.owner if activity.o
wner %>
5: added comment to <%= link_to activity.trackable.shipment.name, activi
ty.trackable.shipment %>
6: <% end %>
app/views/activities/index.html.erb:5:in `block in _app_views_activities_index
_html_erb___51428318_40366872'
app/views/activities/index.html.erb:2:in `_app_views_activities_index_html_erb
___51428318_40366872'

Answer 1

What Ryan fails to mention in the Railscast is that you may get activities belonging to different types of trackables.
So if you have set up tracking for the shipment model:
class Shipment < ActiveRecord::Base
include PublicActivity::Model
tracked
# ...
belongs_to :user
has_many :comments, dependent: :destroy
end
And created a few shipment records and a few commends than your activities table will contains something like this
id trackable_type # ...
1 Shipment
2 Shipment
3 Comment
Here are two possible solutions:
1. Filter the query for one type of trackable.
#activities = PublicActivity::Activity.order("created_at desc")
.where(trackable_type: "Comment")
2. Use different partials for each type of trackable:
<% #activities.each do |activity| %>
<%= render partial "activities/#{ activity.trackable.model_name.singular }",
activity: activity,
object: activity.trackable,
owner: activity.owner
%>
<% end %>
What this does is render app/views/activities/_comment.html.erb or _shipment.html.erb depending on the type. We also setup some local variables so that we don't have to write activity.foo.bar.baz.
We also use the object option which creates an instance variable (an # variable) with the same name as the partial. So in it would be #shipment in _shipment.html.erb.
So in your _comment.html.erb you would do:
<div class="activity">
<%= link_to owner.full_name, owner if owner %>
added comment to <%= link_to #comment.shipment.name, #comment.shipment %>
</div>
See also:
http://guides.rubyonrails.org/layouts_and_rendering.html#using-partials
https://github.com/chaps-io/public_activity#displaying-activities