com.github.gvolpe.fs2rabbit.json.Fs2JsonEncoder.scala Maven / Gradle / Ivy
/*
* Copyright 2017 Fs2 Rabbit
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.gvolpe.fs2rabbit.json
import cats.effect.Sync
import com.github.gvolpe.fs2rabbit.model.AmqpMessage
import com.github.gvolpe.fs2rabbit.typeclasses.StreamEval
import fs2.Pipe
import io.circe.Encoder
import io.circe.syntax._
/**
* Stream-based Json Encoder that exposes only one method as a streaming transformation
* using [[fs2.Pipe]] and depends on the Circe library.
* */
class Fs2JsonEncoder[F[_]: Sync](implicit SE: StreamEval[F]) {
/**
* It tries to encode a given case class encapsulated in an [[AmqpMessage]] into a
* json string.
*
* For example:
*
* {{{
* import fs2._
*
* val payload = Person("Sherlock", Address(212, "Baker St"))
* val p = Stream(AmqpMessage(payload, AmqpProperties.empty)).covary[IO] through jsonEncode[IO, Person]
*
* p.run.unsafeRunSync
* }}}
*
* The result will be an [[AmqpMessage]] of type [[String]]
* */
def jsonEncode[A: Encoder]: Pipe[F, AmqpMessage[A], AmqpMessage[String]] =
streamMsg =>
for {
amqpMsg <- streamMsg
json <- SE.evalF[String](amqpMsg.payload.asJson.noSpaces)
} yield AmqpMessage(json, amqpMsg.properties)
}