RequestHeaderMapMethodArgumentResolver.java

/*
 * Copyright 2002-2016 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
 *
 *      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 org.springframework.web.reactive.result.method.annotation;

import java.util.Map;

import reactor.core.publisher.Mono;

import org.springframework.core.MethodParameter;
import org.springframework.http.HttpHeaders;
import org.springframework.ui.ModelMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.reactive.result.method.HandlerMethodArgumentResolver;
import org.springframework.web.server.ServerWebExchange;

/**
 * Resolves {@link Map} method arguments annotated with {@code @RequestHeader}.
 * For individual header values annotated with {@code @RequestHeader} see
 * {@link RequestHeaderMethodArgumentResolver} instead.
 *
 * <p>The created {@link Map} contains all request header name/value pairs.
 * The method parameter type may be a {@link MultiValueMap} to receive all
 * values for a header, not only the first one.
 *
 * @author Rossen Stoyanchev
 * @see RequestHeaderMethodArgumentResolver
 */
public class RequestHeaderMapMethodArgumentResolver implements HandlerMethodArgumentResolver {

	@Override
	public boolean supportsParameter(MethodParameter parameter) {
		return (parameter.hasParameterAnnotation(RequestHeader.class) &&
				Map.class.isAssignableFrom(parameter.getParameterType()));
	}

	@Override
	public Mono<Object> resolveArgument(MethodParameter parameter, ModelMap model, ServerWebExchange exchange) {
		HttpHeaders headers = exchange.getRequest().getHeaders();
		if (MultiValueMap.class.isAssignableFrom(parameter.getParameterType())) {
			return Mono.just(headers);
		}
		else {
			return Mono.just(headers.toSingleValueMap());
		}
	}

}