org.springframework.web.filter.CorsFilter 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;
import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.util.Assert;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.CorsConfigurationSource;
import org.springframework.web.cors.CorsProcessor;
import org.springframework.web.cors.CorsUtils;
import org.springframework.web.cors.DefaultCorsProcessor;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
/**
* {@link javax.servlet.Filter} that handles CORS preflight requests and intercepts
* CORS simple and actual requests thanks to a {@link CorsProcessor} implementation
* ({@link DefaultCorsProcessor} by default) in order to add the relevant CORS
* response headers (like {@code Access-Control-Allow-Origin}) using the provided
* {@link CorsConfigurationSource} (for example an {@link UrlBasedCorsConfigurationSource}
* instance.
*
* This is an alternative to Spring MVC Java config and XML namespace CORS configuration,
* useful for applications depending only on spring-web (not on spring-webmvc) or for
* security constraints requiring CORS checks to be performed at {@link javax.servlet.Filter}
* level.
*
*
This filter could be used in conjunction with {@link DelegatingFilterProxy} in order
* to help with its initialization.
*
* @author Sebastien Deleuze
* @since 4.2
* @see CORS W3C recommendation
*/
public class CorsFilter extends OncePerRequestFilter {
private final CorsConfigurationSource configSource;
private CorsProcessor processor = new DefaultCorsProcessor();
/**
* Constructor accepting a {@link CorsConfigurationSource} used by the filter
* to find the {@link CorsConfiguration} to use for each incoming request.
* @see UrlBasedCorsConfigurationSource
*/
public CorsFilter(CorsConfigurationSource configSource) {
Assert.notNull(configSource, "CorsConfigurationSource must not be null");
this.configSource = configSource;
}
/**
* Configure a custom {@link CorsProcessor} to use to apply the matched
* {@link CorsConfiguration} for a request.
*
By default {@link DefaultCorsProcessor} is used.
*/
public void setCorsProcessor(CorsProcessor processor) {
Assert.notNull(processor, "CorsProcessor must not be null");
this.processor = processor;
}
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
FilterChain filterChain) throws ServletException, IOException {
CorsConfiguration corsConfiguration = this.configSource.getCorsConfiguration(request);
boolean isValid = this.processor.processRequest(corsConfiguration, request, response);
if (!isValid || CorsUtils.isPreFlightRequest(request)) {
return;
}
filterChain.doFilter(request, response);
}
}