Ruby/Rails library for DRYing up resource access

Question

A common pattern in a Rails controller action is to

1. Fetch a resource
2. Do something to the resource (optional)
3. Return the resource in a serialized format.

I am looking for a library that abstracts away the first step, so that my controller actions can assume a resource was successfully fetched and avoid checks for exceptional cases.

For example, here is a hypothetical show action:

def show
  attrs   = params.slice(:handle, :provider)
  account = Account.find_by(attrs)

  if account
    respond_with account
  else
    head 404
  end
end

And what I want is something more like this:

# controller
def show
  respond_with resource
end

# some initializer (basically pseudocode)
resource do |params|
  attrs = params.slice(:handle, :provider)
  Account.find_by(attrs)
end

Where the library would handle returning a 404 if find_by returns nil, or 400 if the provided params are invalid (missing :handle key, include an extra :id key, etc.).

Does anyone know of a library that provides something like this? It is a great use case for a Rack middleware on top of Application.routes.

Answer 1

The gem platformatec/inherited_resources does something very close to this.