How to create a graphql schema that can be searched on different fields? - scala

Question

I'm testing out sangria to build a graphql/relay server. I have a very simple User class:
case class User(
id: Int,
username: String,
gender: Gender.Value)
I want to allow queries by either ID or username. I have created a schema that allows this, but the fields have different names:
val Query = ObjectType(
"Query", fields[UserRepo, Unit](
Field("user", OptionType(User),
arguments = ID :: Nil,
resolve = ctx => ctx.ctx.getUser(ctx arg ID)),
Field("userByUsername", OptionType(User),
arguments = Username :: Nil,
resolve = ctx => ctx.ctx.getUserByUsername(ctx arg Username))
))
Unfortunately, I need to query these with different fields names, user and userByUsername, e.g.:
curl -G localhost:8080/graphql
--data-urlencode 'query={userByUsername(username: "Leia Skywalker") {id, username, gender}}'
or
curl -G localhost:8080/graph
--data-urlencode "query={user(id: 1025) {id, username, gender}}"
How can I create a schema that allows a single field called user to be queried on either ID or username? E.g. both of the following should return the same user object:
curl -G localhost:8080/graphql
--data-urlencode 'query={user(username: "Leia Skywalker") {id, username, gender}}'
or
curl -G localhost:8080/graph
--data-urlencode "query={user(id: 1025) {id, username, gender}}"

Answer 1

I finally worked it out:
val ID = Argument("id", OptionInputType(IntType), description = "id of the user")
val Username = Argument("username", OptionInputType(StringType), description = "username of the user")
val Query = ObjectType(
"Query", fields[UserRepo, Unit](
Field("user", OptionType(User),
arguments = List(ID, Username),
resolve = ctx => ctx.ctx.getUser(ctx.argOpt(ID), ctx.argOpt(Username)))
))
And getUser looks like:
def getUser(id: Option[Int], username: Option[String]): Option[User] = {
if (id.isEmpty && username.isEmpty) {
None
}
else {
id.flatMap(i => users.find(_.id == i))
.orElse(username.flatMap(u => users.find(_.username == u)))
}
}