Ratpack has the class ratpack.handling.ReponseTimer which adds a header with the name X-Response-Time to the response. The value is the time spent in code from when the request comes in and the response is sent out. ResponseTimer is a handler we can add in our application. Alternatively we can use the static method decorator to get a handler decorator. With a handler decorator we can use the registry to add handler logic in our application.

First we use the ResponseTimer as a handler:

@Grab("io.ratpack:ratpack-groovy:1.1.1")
import ratpack.handling.ResponseTimer

import static ratpack.groovy.Groovy.ratpack

ratpack {
    handlers {
        // Add ResponseTimer for
        // all requests.
        all(new ResponseTimer())

        get {
            render "Ratpack rocks!"
        }
    }
}

We get the same result if we add the handler decorator via the registry:

@Grab("io.ratpack:ratpack-groovy:1.1.1")
import ratpack.handling.ResponseTimer

import static ratpack.groovy.Groovy.ratpack

ratpack {
    bindings {
        // Add ResponseTimer for
        // all requests.
        bindInstance(ResponseTimer.decorator())
    }
    handlers {
        get {
            render "Ratpack rocks!"
        }
    }
}

When we make a request and look at the response header we see a header with the name X-Response-Time:

$ http localhost:5050
X-Response-Time: 1.00000
connection: keep-alive
content-encoding: gzip
content-type: text/plain;charset=UTF-8
transfer-encoding: chunked

Ratpack rocks!

$

Written with Ratpack 1.1.1.

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