Experimental GraphQL client for Scala and Scala.js.
Either:
- A
FetchClient[F[_], S](supporting queries and mutations), or - A
StreamingClient[F[_], S](supporting queries, mutations and subscriptions).
S is a type denoting the schema. It can be any type, even a phantom type. It's only used to type-match clients and operations.
import clue.*
import cats.effect.IO
sealed trait StarWars
// Scala JVM and Scala.js with http4s Ember client
import org.http4s.ember.client.EmberClientBuilder
EmberClientBuilder
.default[IO]
.build
.use: client =>
given Backend[IO] = Http4sHttpBackend[IO](client)
val fetchClient: FetchClient[IO, StarWars] =
Http4sHttpClient.of[IO, StarWars]("https://starwars.com/graphql")
// Scala JVM with JDK WS client behind http4s
import import org.http4s.jdkhttpclient.JdkWSClient
JdkWSClient
.simple[IO]
.use: client =>
given StreamingBackend[IO] = Http4sWebSocketBackend[IO](client)
val streamingClient: StreamingClient[IO, StarWars] =
Http4sWebSocketClient.of[IO, StarWars]("wss://starwars.com/graphql")
// Scala.js with default fetch/WS client
import clue.js.*
given Backend[IO] = AjaxJSBackend[IO]
val fetchClient: FetchClient[IO, StarWars] =
FetchJsClient.of[IO, StarWars]("https://starwars.com/graphql")
// Streaming doesn't require Apollo, it just follows the Apollo protocol for GraphQL over WS
given StreamingBackend[IO] = WebSocketJsBackend[IO]
val streamingClient: StreamingClient[IO, StarWars] =
ApolloStreamingClient.of[IO, StarWars]("wss://starwars.com/graphql")They must extend GraphQLOperation[S], defining the following members:
val document: String
type Variables
type Data
val varEncoder: io.circe.Encoder.AsObject[Variables]
val dataDecoder: io.circe.Decoder[Data] import io.circe._
import io.circe.generic.semiauto._
object CharacterQuery extends GraphQLOperation[StarWars] {
val document = """
query (charId: ID!) {
character(id: $charId) {
id
name
}
}
"""
case class Variables(charId: String)
case class Character(id: String, name: Option[String])
object Character {
implicit val characterDecoder: Decoder[Character] = deriveDecoder[Character]
}
case class Data(character: Option[Character])
val varEncoder: Encoder[Variables] = deriveEncoder[Variables]
val dataDecoder: Decoder[Data] = deriveDecoder[Data]
}fetchClient.request(CharacterQuery)(CharacterQuery.Variables("0001"))
.forEach(println).unsafeRunSync()
# Data(Some(Character("0001", Some("Luke"))))