Question

I am running Ruby on Rails 3 and I have an application that makes use of namespaces in order to handle more “internal concepts”. With “internal concepts” I mean that each namespace is used to handle a specific resource of my application. For example a namespace is “users” and it is used to handle user’s sessions and authorizations, another is “blogs” and it is used to handle all about posts and comments.

I think this is a “convenient” solution to avoid a lot of problems, but not the best.

At this time my RoR application consists of this file system structure:

# "users" and "blogs" are namespaces

RAILS_ROOT/app/controllers/users
RAILS_ROOT/app/controllers/blogs
RAILS_ROOT/app/models/users
RAILS_ROOT/app/models/blogs
RAILS_ROOT/app/views/users
RAILS_ROOT/app/views/blogs
...

I would like to switch the “users” and “blogs” namespace in two RoR applications using subdomains to have something like this:

http://main.com        # This is the main RoR application
http://users.main.com  # This is another RoR application used to handle users
http://blogs.main.com  # This is another RoR application used to handle blogs

In few words, I think I am trying to Scale Out* my application or maybe to create a Webservice for each RoR application, but my issues are:

1. What problems I may encounter?

I noticed of problems about maintaining sessions (in my case I handle those with cookies) between applications but I think it isn’t the only one problem.

2. How to handle communication between the three RoR applications in my case?

I noticed that I can use ActiveResource to share information, but I must pay attention to information such as user authentication.

1. I have to implement the OpenID/Oauth protocol in order to maintain user authentications?

2. I think I have to ensure the user authentication information with a HTTPS connection also if the comunication is between subdomains. Is it true?

3. How do I organize my work and resources?

With all that being said, I would like to don’t use (absolutely) plugins or gems, but, if I need, I would like to implement my own handler.

At the end I would like to have 3 RoR “easy” and separated applications without use namespaces in each of them and that can communicate between each other:

# "Main" application for http://main.com
ROOT_MAIN/app/controllers/
ROOT_MAIN/app/models/
ROOT_MAIN/app/views/users
...

# "Users" application for http://users.main.com
ROOT_USERS/app/controllers/
ROOT_USERS/app/models/
ROOT_USERS/app/views/users
...

# "Blogs" application for http://blogs.main.com
ROOT_BLOGS/app/controllers/
ROOT_BLOGS/app/models/
ROOT_BLOGS/app/views/users
...

BTW: is a good approach the usage of namespaces that I’m doing?

P.S.: If you need some other information, let me know and I will update the question.

---

*From The O2 Software Process: “Scale Out” refers to the concept of adding more servers to an existing park, as opposed to “Scale Up” which means to replace existing (slow) servers with newer (and faster) servers.

Answer 1

Is your app really so big that you need to use multiple apps to handle the different concerns? It could be that your post just lacks enough detail to convey the real magnitude of what you are doing but it seems like you are trying to modularize a small enough app that it would be fine without “scaling out” as you say. Or maybe I am just missing something?

1. I think that is going to be a tricky problem but there may be some way to store session data in the database and either share it the way you handle #2 or you’ll have to roll a custom solution for that. I think the biggest problem will be sharing resources across your app, and also if you are breaking user management out into its own app you’ll need to implement your own OpenID/Oauth. This post describes this with Devise/OAuth.

2. You can use activeresource to connect to each app’s respective rest api. This post describes one guy’s solutions to sharing data across rails apps.

3. This question is somewhat vague. You described using multiple apps to separate your concerns (blogging vs user management), so I imagine you’ll have your resources at the root of each application without any namespacing, as you’ve done already in your existing application.

Now for a more general response to your entire question, recently I read a blog post regarding Data, Context and Interaction (wikipedia article) on Rails, and I think this might be a better solution for what you are trying to accomplish if you feel like your app is getting out of control.