Activities is a gem that enables social activities in ActiveRecord objects.

sudo gem install activities

You have to create a migration.

• Rails 2: script/generate migration create_activities

• Rails 3: rails generate migration create_activities

Then paste the following code.

class CreateActivities < ActiveRecord::Migration
  def self.up
    create_table :activities do |t|
      t.references :tracker, :polymorphic => true, :null => false
      t.references :trackable, :polymorphic => true, :null => false
      t.string :action, :null => false
      t.text :data, :null => true
      t.timestamps
    end

    add_index :activities, [:tracker_id, :trackable_id]
    add_index :activities, [:tracker_id, :trackable_id, :action]
  end

  def self.down
    drop_table :activities
  end
end

If you want the source go to github.com/fnando/activities

Activities is plugged on associations. So, all you have to do is add something like this:

class User < ActiveRecord::Base
  has_many :projects
  activities_for :projects do
    track :renamed, :if => proc {|r| !r.new_record? && r.name_changed? }, :on => :save
    track :create
    track :update
    track :destroy
  end
end

This will add activities when you create, update, destroy a project or the change its name.

To retrieve the activities, you can use the association activities.

@user.activities.all

By default, all attributes are stored in a field called data. You should overwrite the method to_activity and return a hash with the attributes that you really want to be saved.

class Project < ActiveRecord::Base
  belongs_to :user

  def to_activity
    { :name => name, :status => status }
  end
end

To display the activities, you should use the helper render_activity.

<% for activity in @activities %>
  <%= render_activity @activity %>
<% end %>

The render_activity helper will render a partial as app/views/activities/TRACKABLE_TYPE/ACTION. So, if you want to render activities for that project, you should create the following files:

app/views/activities/project/_renamed.html.erb
app/views/activities/project/_create.html.erb
app/views/activities/project/_update.html.erb
app/views/activities/project/_destroy.html.erb

The activity object will be available and you can display something like this:

<p>
  <%= tracker.name %> created the
  repository <%= link_to data[:name], project_path(trackable) %>
  <%= time_ago_in_words data[:created_at] %>
</p>

(The MIT License)

Copyright © 2010:

• Nando Vieira - nandovieira.com.br

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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