org.springframework.web.reactive.result.method.annotation.RequestAttributeMethodArgumentResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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 reactor.core.publisher.Mono;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.core.MethodParameter;
import org.springframework.core.ReactiveAdapter;
import org.springframework.core.ReactiveAdapterRegistry;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.bind.annotation.RequestAttribute;
import org.springframework.web.bind.annotation.ValueConstants;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.ServerWebInputException;
/**
* Resolves method arguments annotated with an @{@link RequestAttribute}.
*
* @author Rossen Stoyanchev
* @since 5.0
* @see SessionAttributeMethodArgumentResolver
*/
public class RequestAttributeMethodArgumentResolver extends AbstractNamedValueSyncArgumentResolver {
/**
* @param factory a bean factory to use for resolving ${...}
* placeholder and #{...} SpEL expressions in default values;
* or {@code null} if default values are not expected to have expressions
* @param registry for checking reactive type wrappers
*/
public RequestAttributeMethodArgumentResolver(@Nullable ConfigurableBeanFactory factory,
ReactiveAdapterRegistry registry) {
super(factory, registry);
}
@Override
public boolean supportsParameter(MethodParameter param) {
return param.hasParameterAnnotation(RequestAttribute.class);
}
@Override
protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
RequestAttribute ann = parameter.getParameterAnnotation(RequestAttribute.class);
Assert.state(ann != null, "No RequestAttribute annotation");
return new NamedValueInfo(ann.name(), ann.required(), ValueConstants.DEFAULT_NONE);
}
@Override
protected Object resolveNamedValue(String name, MethodParameter parameter, ServerWebExchange exchange) {
Object value = exchange.getAttribute(name);
ReactiveAdapter toAdapter = getAdapterRegistry().getAdapter(parameter.getParameterType());
if (toAdapter != null) {
if (value == null) {
Assert.isTrue(toAdapter.supportsEmpty(),
() -> "No request attribute '" + name + "' and target type " +
parameter.getGenericParameterType() + " doesn't support empty values.");
return toAdapter.fromPublisher(Mono.empty());
}
if (parameter.getParameterType().isAssignableFrom(value.getClass())) {
return value;
}
ReactiveAdapter fromAdapter = getAdapterRegistry().getAdapter(value.getClass());
Assert.isTrue(fromAdapter != null,
() -> getClass().getSimpleName() + " doesn't support " +
"reactive type wrapper: " + parameter.getGenericParameterType());
return toAdapter.fromPublisher(fromAdapter.toPublisher(value));
}
return value;
}
@Override
protected void handleMissingValue(String name, MethodParameter parameter) {
String type = parameter.getNestedParameterType().getSimpleName();
String reason = "Missing request attribute '" + name + "' of type " + type;
throw new ServerWebInputException(reason, parameter);
}
}