Adapt Enumerator / Iteratee to Stream

Question

I have a Spray application where I'm using reactive-mongo to connect to my Mongo database.

val collection: BSONCollection = db("ping")
val cursor: Cursor[Ping] = collection.find(BSONDocument()).cursor[Ping]
val e: Enumerator[Ping] = cursor.enumerate()

ReactiveMongo's cursor allows me to get the data by chunks. This cursor can be transformed to a play.api.libs.iteratee.Enumerator which is in turn connected to a play.api.libs.iteratee.Iteratee where any code I want is called for each element of the collection. "Ping" is my domain entity.

With Spray it's possible to return a Stream[Ping] that will be marshalled into a JSON response. I'd like to know if it's possible to adapt the Enumerator or the Iteratee to a Stream, so I can return that.

Answer 1

You can use collect[Stream] instead of enumerate on the Cursor instance to do that:

val collection: BSONCollection = db("ping")
val cursor: Cursor[Ping] = collection.find(BSONDocument()).cursor[Ping]
val stream: Stream[Ping] = cursor.toList.toStream

EDIT: Used cursor.toList.toStream. This will gather all the documents matched by the query, then produce a stream.