Creating an activity feed

A lot of applications (well, a few at least) have required some sort of “recent activity” feed. You know, for a dashboard or something. It’s a pretty straight-forward thing to do, but I thought I might mention how I typically go about it, and see if anyone else has suggestions/improvements. I have some ideas for a useful plugin, so I’ll be working toward that soon.

An activity feed isn’t really all that useful if it’s only showing you the latest of one thing. Like comments, for example. More than likely you’ll want the most recent comments, articles, uploaded pictures, messages, etc, all in one place, and all over one iteration. What I do is create a class in the app/models directory that doesn’t inherit from ActiveRecord. Then, using named_scope’s, I just build a collection of objects. Here’s an example:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

class Activity
  def initialize(user)
    @user = user
  end
  
  def recent(options = {})
    limit = options[:limit] || 15
    
    returning([]) do |collection|
      collection << Article.recent.all(:limit => limit)
      collection << Asset.parents.recent.all(:limit => limit)
      collection << Message.sent_to(@user).recent.all(:limit => limit)
    end.flatten.sort_by(&:updated_at).reverse.slice(0, limit)
  end
end

Then to get an array of the most recent articles, assets, and messages, you can simply do:

1

@activity = Activity.new(current_user).recent(:limit => 10)

The next thing I typically do is match icons up to the object type, and render those by convention. So when I’m iterating over an article, for example, I might render an “article-icon.png” as the representative icon. Assets would have “asset-icon.png” and so on.

Keeping this stuff in its own class is nice because you can add methods as needed. For instance, maybe you need some special logic for an RSS feed, well you could add a to_rss method or something that would handle it.

This type of thing typically comes with a group of helpers that format the collection appropriately and represent it in a useful way, but I’ll leave that up to you.