org.springframework.web.server.CoWebFilter.kt Maven / Gradle / Ivy
/*
* Copyright 2002-2023 the original author or authors.
*
* 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
*
* https://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 org.springframework.web.server
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.currentCoroutineContext
import kotlinx.coroutines.reactor.awaitSingleOrNull
import kotlinx.coroutines.reactor.mono
import reactor.core.publisher.Mono
import kotlin.coroutines.CoroutineContext
/**
* Kotlin-specific implementation of the [WebFilter] interface that allows for
* using coroutines.
*
* @author Arjen Poutsma
* @author Sebastien Deleuze
* @since 6.0.5
*/
abstract class CoWebFilter : WebFilter {
final override fun filter(exchange: ServerWebExchange, chain: WebFilterChain): Mono {
val context = exchange.attributes[COROUTINE_CONTEXT_ATTRIBUTE] as CoroutineContext?
return mono(context ?: Dispatchers.Unconfined) {
filter(exchange, object : CoWebFilterChain {
override suspend fun filter(exchange: ServerWebExchange) {
exchange.attributes[COROUTINE_CONTEXT_ATTRIBUTE] = currentCoroutineContext().minusKey(Job.Key)
chain.filter(exchange).awaitSingleOrNull()
}
})}.then()
}
/**
* Process the Web request and (optionally) delegate to the next
* [WebFilter] through the given [WebFilterChain].
* @param exchange the current server exchange
* @param chain provides a way to delegate to the next filter
*/
protected abstract suspend fun filter(exchange: ServerWebExchange, chain: CoWebFilterChain)
companion object {
/**
* Name of the [ServerWebExchange] attribute that contains the
* [kotlin.coroutines.CoroutineContext] to be passed to the
* [org.springframework.web.reactive.result.method.InvocableHandlerMethod].
*/
@JvmField
val COROUTINE_CONTEXT_ATTRIBUTE = CoWebFilter::class.java.getName() + ".context"
}
}
/**
* Kotlin-specific adaption of [WebFilterChain] that allows for coroutines.
*
* @author Arjen Poutsma
* @since 6.0.5
*/
interface CoWebFilterChain {
/**
* Delegate to the next [WebFilter] in the chain.
* @param exchange the current server exchange
*/
suspend fun filter(exchange: ServerWebExchange)
}