org.springframework.web.filter.reactive.HiddenHttpMethodFilter Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
import reactor.core.publisher.Mono;
import org.springframework.http.HttpMethod;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
/**
* Reactive {@link WebFilter} that converts posted method parameters into HTTP methods,
* retrievable via {@link ServerHttpRequest#getMethod()}. Since browsers currently only
* support GET and POST, a common technique is to use a normal POST with an additional
* hidden form field ({@code _method}) to pass the "real" HTTP method along.
* This filter reads that parameter and changes the {@link ServerHttpRequest#getMethod()}
* return value using {@link ServerWebExchange#mutate()}.
*
* The name of the request parameter defaults to {@code _method}, but can be
* adapted via the {@link #setMethodParamName(String) methodParamName} property.
*
* @author Greg Turnquist
* @author Rossen Stoyanchev
* @since 5.0
*/
public class HiddenHttpMethodFilter implements WebFilter {
private static final List ALLOWED_METHODS =
Collections.unmodifiableList(Arrays.asList(HttpMethod.PUT,
HttpMethod.DELETE, HttpMethod.PATCH));
/** Default name of the form parameter with the HTTP method to use. */
public static final String DEFAULT_METHOD_PARAMETER_NAME = "_method";
private String methodParamName = DEFAULT_METHOD_PARAMETER_NAME;
/**
* Set the name of the form parameter with the HTTP method to use.
* By default this is set to {@code "_method"}.
*/
public void setMethodParamName(String methodParamName) {
Assert.hasText(methodParamName, "'methodParamName' must not be empty");
this.methodParamName = methodParamName;
}
/**
* Transform an HTTP POST into another method based on {@code methodParamName}.
* @param exchange the current server exchange
* @param chain provides a way to delegate to the next filter
* @return {@code Mono} to indicate when request processing is complete
*/
@Override
public Mono filter(ServerWebExchange exchange, WebFilterChain chain) {
if (exchange.getRequest().getMethod() != HttpMethod.POST) {
return chain.filter(exchange);
}
return exchange.getFormData()
.map(formData -> {
String method = formData.getFirst(this.methodParamName);
return StringUtils.hasLength(method) ? mapExchange(exchange, method) : exchange;
})
.flatMap(chain::filter);
}
private ServerWebExchange mapExchange(ServerWebExchange exchange, String methodParamValue) {
HttpMethod httpMethod = HttpMethod.resolve(methodParamValue.toUpperCase(Locale.ENGLISH));
Assert.notNull(httpMethod, () -> "HttpMethod '" + methodParamValue + "' not supported");
if (ALLOWED_METHODS.contains(httpMethod)) {
return exchange.mutate().request(builder -> builder.method(httpMethod)).build();
}
else {
return exchange;
}
}
}