korolev.server.StateLoader.scala Maven / Gradle / Ivy
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/*
* 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.server
import korolev.effect.Effect
import korolev.state.DeviceId
import korolev.web.Request.Head
object StateLoader {
/**
* State is same for all sessions.
*
* @param initialState
* State factory
* @tparam S
* Type of state
*/
def default[F[_]: Effect, S](initialState: S): StateLoader[F, S] = {
val value = Effect[F].pure(initialState)
(_, _) => value // always return same object
}
/**
* State depends on deviceId. Useful when you want to restore user
* authorization.
*
* {{{
* case class MyState(deviceId: DeviceId, ...)
*
* StateLoader.forDeviceId { deviceId =>
* MyStorage.getStateByDeviceId(deviceId) map {
* case Some(state) => state
* case None => MyState(deviceId, ...)
* }
* }
* }}}
*/
def forDeviceId[F[_], S](initialState: DeviceId => F[S]): StateLoader[F, S] =
(deviceId, _) => initialState(deviceId)
/**
* State depends on deviceId and HTTP-request. Second one could be None if
* case when user reconnected to restarted application and state wasn't
* restored.
*/
def apply[F[_], S](f: (DeviceId, Head) => F[S]): StateLoader[F, S] = f
}