We have talked about routes, and how to pass parameters to controllers. Let's now talk about what we can do with the controller.
The method defined in the route must return a
play.api.mvc.Action instance. The
Action type is a thin wrapper around the type
Request[A] => Result, where
Request[A] identifies an HTTP request and
Result is an HTTP response.
Composing the response
An HTTP response, as we saw in Chapter 7, Web APIs, is composed of:
- the status code (such as 200 for a successful response, or 404 for a missing page)
- the response headers, a key-value list indicating metadata related to the response
- The response body. This can be HTML for web pages, or JSON, XML or plain text (or many other formats). This is generally the bit that we are ...