Streaming results using enumerators

Iteratees make it possible to consume streams of data in a non-blocking way. Conversely, enumerators produce data streams in a non-blocking way. They are useful when you need to send large results, or if your result is built from an intermittent data source. An Enumerator[A] object defines a stream of values of type A.

The simplest way to create an enumerator is to use one of the methods of the Enumerator object. For instance, you can easily convert a java.io.InputStream class or a java.io.File class to an Enumerator[Array[Byte]] object as follows:

import play.api.libs.iteratee.Enumerator
Enumerator.fromStream(inputStream)
Enumerator.fromFile(file)

To send a stream of data as a response body, it is better to explicitly set the Content-Length response header so that the connection can be kept alive to serve further requests. Alternatively, you can use the chunked transfer encoding as follows:

Ok.chunked(Enumerator.fromFile(new File("foo.txt")))

To use the chunked...