import scala.util.Try
import reactivemongo.api.bson.{ BSONReader, BSONValue }

def fromBSON[T](bson: BSONValue)(implicit r: BSONReader[T]): Try[T] =
 r.readTry(bson)

Concrete methods

Prepares a BSONReader that returns the result of applying f on the result of this reader.

import scala.util.Try
import reactivemongo.api.bson.{ BSONReader, BSONValue }

// Try to return an integer + 1,
// from any T that can be read from BSON
// and is a numeric type
def fromBSON[T](bson: BSONValue)(
 implicit r: BSONReader[T], n: Numeric[T]): Try[Int] = {
 val r2: BSONReader[Int] = r.afterRead { v => n.toInt(v) + 1 }
 r2.readTry(bson)
}

Value parameters:

f: the function to apply

Prepares a BSONReader that transforms the input BSON value, using the given f function, before passing the transformed BSON value to the current reader.

import reactivemongo.api.bson.{
 BSONReader, BSONInteger, BSONNull, BSONString
}

val normalizingReader: BSONReader[Int] =
 implicitly[BSONReader[Int]].beforeRead {
   case BSONNull => BSONInteger(-1)
   case BSONString(s) => BSONInteger(s.size)
   // other values are unchanged
 }

normalizingReader.readOpt(BSONNull) // Some(-1)
normalizingReader.readTry(BSONString("foo")) // Success(3)
normalizingReader.readOpt(BSONInteger(4)) // unchanged: Some(4)

Prepares a BSONReader that transforms the input BSON value, using the given f function, before passing the transformed BSON value to the current reader.

Tries to produce an instance of T from the bson value, returns None if an error occurred.

import reactivemongo.api.bson.{ BSONReader, BSONValue }

def fromBSON[T](bson: BSONValue)(implicit r: BSONReader[T]): Option[T] =
 r.readOpt(bson)

Tries to produce an instance of T from the bson value, returns the default value if an error occurred.

import reactivemongo.api.bson.{ BSONReader, BSONValue }

def fromBSON[T](bson: BSONValue, v: T)(implicit r: BSONReader[T]): T =
 r.readOrElse(bson, v)

@SuppressWarnings(scala.Array.apply[java.lang.String]("AsInstanceOf")(scala.reflect.ClassTag.apply[java.lang.String](classOf[java.lang.String])))

Widens this reader for a compatible type U.

import reactivemongo.api.bson.BSONReader

val listReader: BSONReader[List[String]] =
 implicitly[BSONReader[List[String]]]

val widenAsSeqReader: BSONReader[Seq[String]] =
 listReader.widen[Seq[String]]
 // as Seq[String] >: List[String]

Type parameters:

U: must be a super-type of T