Answer by pixeltrix for API Versioning for Rails Routes

A couple of things to add:

Your redirect match isn't going to work for certain routes - the *api param is greedy and will swallow up everything, e.g. /api/asdf/users/1 will redirect to /api/v2/1. You'd be better off using a regular param like :api. Admittedly it won't match cases like /api/asdf/asdf/users/1 but if you have nested resources in your api it's a better solution.

Ryan WHY U NO LIKE namespace? :-), e.g:

current_api_routes = lambda do  resources :usersendnamespace :api do  scope :module => :v2, &current_api_routes  namespace :v2, &current_api_routes  namespace :v1, &current_api_routes  match ":api/*path", :to => redirect("/api/v2/%{path}")end

Which has the added benefit of versioned and generic named routes. One additional note - the convention when using :module is to use underscore notation, e.g: api/v1 not 'Api::V1'. At one point the latter didn't work but I believe it was fixed in Rails 3.1.

Also, when you release v3 of your API the routes would be updated like this:

current_api_routes = lambda do  resources :usersendnamespace :api do  scope :module => :v3, &current_api_routes  namespace :v3, &current_api_routes  namespace :v2, &current_api_routes  namespace :v1, &current_api_routes  match ":api/*path", :to => redirect("/api/v3/%{path}")end

Of course it's likely that your API has different routes between versions in which case you can do this:

current_api_routes = lambda do  # Define latest APIendnamespace :api do  scope :module => :v3, &current_api_routes  namespace :v3, &current_api_routes  namespace :v2 do    # Define API v2 routes  end  namespace :v1 do    # Define API v1 routes  end  match ":api/*path", :to => redirect("/api/v3/%{path}")end