Rails 4 - Respond only to JSON and not HTML

Question

I\'m trying to build an API in rails 4, and am having an issue where rails returns a 500 error instead of a 406 when using respond_to :json and trying to access

Answer 1

In Rails 4, you need to pass a lambda to enforce the constraint on a route.

Unfortunately, this will NOT work because it will still try to serve up (or attempt to serve up) an html template since the format is an optional parameter:

resources :posts, constraints: { format: 'json' }

This DOES work (uses the lambda):

resources :posts, constraints: lambda { |req| req.format == :json }

See the second (final) note in this section of the Rails guide.