org.springframework.web.filter.reactive.ServerWebExchangeContextFilter Maven / Gradle / Ivy
/*
* Copyright 2002-2019 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.filter.reactive;
import java.util.Optional;
import reactor.core.publisher.Mono;
import reactor.util.context.Context;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
/**
* Inserts an attribute in the Reactor {@link Context} that makes the current
* {@link ServerWebExchange} available under the attribute name
* {@link #EXCHANGE_CONTEXT_ATTRIBUTE}. This is useful for access to the
* exchange without explicitly passing it to components that participate in
* request processing.
*
* The convenience method {@link #get(Context)} looks up the exchange.
*
* @author Rossen Stoyanchev
* @since 5.2
*/
public class ServerWebExchangeContextFilter implements WebFilter {
/** Attribute name under which the exchange is saved in the context. */
public static final String EXCHANGE_CONTEXT_ATTRIBUTE =
ServerWebExchangeContextFilter.class.getName() + ".EXCHANGE_CONTEXT";
@Override
public Mono filter(ServerWebExchange exchange, WebFilterChain chain) {
return chain.filter(exchange)
.subscriberContext(cxt -> cxt.put(EXCHANGE_CONTEXT_ATTRIBUTE, exchange));
}
/**
* Access the {@link ServerWebExchange} from the Reactor Context, if available,
* which is if {@link ServerWebExchangeContextFilter} is configured for use
* and the give context was obtained from a request processing chain.
* @param context the context in which to access the exchange
* @return the exchange
*/
public static Optional get(Context context) {
return context.getOrEmpty(EXCHANGE_CONTEXT_ATTRIBUTE);
}
}