Streama is a simple Ruby activity stream gem for use with the Mongoid ODM framework.
It works by posting to and querying from a firehose of individual activity items.
Currently Streama uses a Fan Out On Read approach. This is great for single instance databases, however if you plan on Sharding then please be aware that it'll hit every shard when querying. I plan on changing the schema soon so that it Fans Out On Write with bucketing.
Data Modeling Examples from the real world
gem install streama
Create an Activity model and define the activities and the fields you would like to cache within the activity.
An activity consists of an actor, a verb, an object, and a target.
class Activity
include Streama::Activity
activity :new_photo do
actor :user, :cache => [:full_name]
object :photo, :cache => [:subject, :comment]
target_object :album, :cache => [:title]
end
end
The activity verb is implied from the activity name, in the above example the verb is :new_photo
The object may be the entity performing the activity, or the entity on which the activity was performed. e.g John(actor) shared a video(object)
The target is the object that the verb is enacted on. e.g. Geraldine(actor) posted a photo(object) to her album(target)
This is based on the Activity Streams 1.0 specification (http://activitystrea.ms)
Include the Actor module in a class and override the default followers method.
class User
include Mongoid::Document
include Streama::Actor
field :full_name, :type => String
def followers
User.excludes(:id => self.id).all
end
end
Create the indexes for the Activities collection. You can do so by calling the create_indexes method.
Activity.create_indexes
In your controller or background worker:
current_user.publish_activity(:new_photo, :object => @photo, :target_object => @album)
This will publish the activity to the mongoid objects returned by the #followers method in the Actor.
To send your activity to different receievers, pass in an additional :receivers parameter.
current_user.publish_activity(:new_photo, :object => @photo, :target_object => @album, :receivers => :friends) # calls friends method
current_user.publish_activity(:new_photo, :object => @photo, :target_object => @album, :receivers => current_user.find(:all, :conditions => {:group_id => mygroup}))
To retrieve the activity stream for an actor
current_user.activity_stream
To retrieve the activity stream and filter by activity type
current_user.activity_stream(:type => :activity_verb)
To retrieve all activities published by an actor
current_user.published_activities
To retrieve all activities published by an actor and filtered by activity type
current_user.published_activities(:type => :activity_verb)
If you need to return the instance of an :actor, :object or :target_object from an activity call the Activity#load_instance method
activity.load_instance(:actor)
You can also refresh the cached activity data by calling the Activity#refresh_data method
activity.refresh_data
Mongoid 4 support added.
Mongoid 3.0 support added.
The Activity "target" field was renamed to "target_object". If you are upgrading from a previous version of Streama you will need to rename the field in existing documents.
http://www.mongodb.org/display/DOCS/Updating#Updating-%24rename
Once you've made your great commits
- Fork
- Create a topic branch - git checkout -b my_branch
- Push to your branch - git push origin my_branch
- Create a Pull Request from your branch
- That's it!