Best practice for extracting data from a response

[jamesarosen]

Here's what I want:

VCR.use_cassette('foo-refresh') do
  subject.refresh()
end
expect(subject.foo).to eq(some_value_from_the_foo_refresh_response)

I could use a Dynamic ERB Cassette and inject the expected value into it. The downside there is that it's something I need to maintain every time the cassette gets re-recorded.

I could use an after_http_request hook, but that has to be configured globally. That means (a) the response parsing looks magical from the perspective of the spec and (b) I need to store the extracted value somewhere global as well.

Does anyone have a good pattern for this?