korolev.Router.scala Maven / Gradle / Ivy
/*
* Copyright 2017-2020 Aleksey Fomkin
*
* 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 korolev
import korolev.effect.Effect
import korolev.effect.syntax._
import korolev.util.Lens
import korolev.web.PathAndQuery
/**
* URL routing definition
*
* @param fromState From current state to Uri
* @param toState From Uri to state
*
* @tparam F A async control
* @tparam S Type of State
*/
final case class Router[F[_], S](
fromState: PartialFunction[S, PathAndQuery],
toState: PartialFunction[PathAndQuery, S => F[S]]
) {
/**
* Compose two routers to one.
* {{{
* val articlesRouter = Router(...)
* val authorsRouter = Router(...)
* val router = articlesRouter ++ authorsRouter
* }}}
*/
def ++(that: Router[F, S]): Router[F, S] =
Router(fromState.orElse(that.fromState), toState.orElse(that.toState))
}
object Router {
def empty[F[_], S]: Router[F, S] = Router(PartialFunction.empty, PartialFunction.empty)
def apply[F[_]: Effect, S, S2](lens: Lens[S, S2])(
fromState: PartialFunction[S2, PathAndQuery] = PartialFunction.empty,
toState: PartialFunction[PathAndQuery, S2 => F[S2]] = PartialFunction.empty): Router[F, S] =
Router(
fromState = lens.read.andThen(fromState),
toState = toState.andThen { f => s =>
lens
.get(s)
.fold(Effect[F].pure(s)) { s2 =>
f(s2).map(newS2 => lens.update(s, newS2))
}
}
)
}