How to get response headers and body in dispatch request? - scala

Question

I want to get both body and headers from dispatch request. How to do this?
val response = Http(request OK as.String)
for (r <- response) yield {
println(r.toString) //prints body
// println(r.getHeaders) // ???? how to print headers here ????
}

Answer 1

We needed the response body of failed requests to an API, so we came up with this solution:
Define your own ApiHttpError class with code and body (for the body text):
case class ApiHttpError(code: Int, body: String)
extends Exception("Unexpected response status: %d".format(code))
Define OkWithBodyHandler similar to what is used in the source of displatch:
class OkWithBodyHandler[T](f: Response => T) extends AsyncCompletionHandler[T] {
def onCompleted(response: Response) = {
if (response.getStatusCode / 100 == 2) {
f(response)
} else {
throw ApiHttpError(response.getStatusCode, response.getResponseBody)
}
}
}
Now, near your call to the code that might throw and exception (calling API), add implicit override to the ToupleBuilder (again similar to the source code) and call OkWithBody on request:
class MyApiService {
implicit class MyRequestHandlerTupleBuilder(req: Req) {
def OKWithBody[T](f: Response => T) =
(req.toRequest, new OkWithBodyHandler(f))
}
def callApi(request: Req) = {
Http(request OKWithBody as.String).either
}
}
From now on, fetching either will give you the [Throwable, String] (using as.String), and the Throwable is our ApiHttpError with code and body.
Hope it helped.

Answer 2

From the Dispatch docs:
import dispatch._, Defaults._
val svc = url("http://api.hostip.info/country.php")
val country = Http(svc OK as.String)
The above defines and initiates a request to the given host where 2xx
responses are handled as a string. Since Dispatch is fully
asynchronous, country represents a future of the string rather than
the string itself.
(source)
In your example, the type of response is Future[String], because 'OK as.String' converts 2xx responses into strings and non-2xx responses into failed futures. If you remove 'OK as.String', you'll get a Future[com.ning.http.client.Response]. You can then use getResponseBody, getHeaders, etc. to inspect the Request object.