An Introduction to the Diaspora Source

Framework and Tools:

Diaspora is written in Ruby on Rails, a web framework for Ruby. If you’ve never looked at a Rails project, you may want to check out a Rails guide like this one.

There are a few tools we’re using that aren’t in every rails project:

Our views are written in HAML, a templating language. The HAML docs are here.

Our CSS is written in SASS, which generates CSS. The syntax is inspired by HAML, and quite similar. If you want to edit the stylesheets, look in public/stylesheets/sass/.

Both HAML and SASS are whitespace sensitive.


Please test your patches. If you find a bug, exposing it with a test is awesome. We write our unit tests in Rspec, and integration tests in Cucumber. We need more integration tests! Specs are in spec/, and Cucumber features are in features/.

The Models:

Our Models can be found in the app/models folder:

User – Users, of course, come first. A User object represents the private information and capabilities of a user on that server. The user object is able to friend people, post updates, and update his profile. A User has a Person.

Person – A Person is a User viewed from the outside. When a user friends another user, they friend that user’s Person object. Person objects are replicated across servers, and they are where a User’s public key lives. A Person has many Posts. A Person has a Profile.

Profile – This contains information about the person. Currently, a profile looks the same to anyone looking at it.

Request – This is a friend request object that gets sent to another person.

Aspect – This is contains a list of people, and posts which are for that aspect. Aspects are private to Users, and we might embed the Aspect documents in the User document.

Post – A Post belongs to a Person. This is a parent class for different types of posts, it contains comment ids and a few other attributes common to all Posts.

  • Status Message inherits from Post
  • Album inherits from Post
  • Photo inherits from Post

Comment – a comment belongs to a Post

Retraction – this is an object that gets sent out when a post creator deletes a post. It is not a model, but it serializes for dispatch to other Diaspora servers the same way our models do.

Posting something (app/models/user):

1) When a user posts anything, he/she posts it to an aspect or all aspects

2) Assuming the post is valid, the post created and its id is stored in raw_visible_posts for that user

3) The html for that post is rendered on the server and is pushed to the user through the websocket

4) The post is then serialized to xml, wrapped in an encrypted and signed salmon envelope and POSTed to the receive urls(“http://pod.location/receive/users/:id[person_id]”) for the recipient people.

Receiving a post (app/controllers/publics_controller.rb & lib/diaspora/user/receiving.rb ):

1) The user receives the salmon, decrypts the headers.

2) If the signature on the salmon data is from the person who claims to have sent to have sent the post the post is marshaled into an object and saved into the database

3) That post id is stored in the visible posts for the receiving user as well as posts for the aspect the sender is in.

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