001/* 002 * Copyright 2002-2018 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.reactive.resource; 018 019import java.util.List; 020 021import reactor.core.publisher.Mono; 022 023import org.springframework.core.io.Resource; 024import org.springframework.lang.Nullable; 025import org.springframework.web.server.ServerWebExchange; 026 027/** 028 * A contract for invoking a chain of {@link ResourceResolver ResourceResolvers} where each resolver 029 * is given a reference to the chain allowing it to delegate when necessary. 030 * 031 * @author Rossen Stoyanchev 032 * @since 5.0 033 */ 034public interface ResourceResolverChain { 035 036 /** 037 * Resolve the supplied request and request path to a {@link Resource} that 038 * exists under one of the given resource locations. 039 * @param exchange the current exchange 040 * @param requestPath the portion of the request path to use 041 * @param locations the locations to search in when looking up resources 042 * @return the resolved resource; or an empty {@code Mono} if unresolved 043 */ 044 Mono<Resource> resolveResource(@Nullable ServerWebExchange exchange, String requestPath, 045 List<? extends Resource> locations); 046 047 /** 048 * Resolve the externally facing <em>public</em> URL path for clients to use 049 * to access the resource that is located at the given <em>internal</em> 050 * resource path. 051 * <p>This is useful when rendering URL links to clients. 052 * @param resourcePath the internal resource path 053 * @param locations the locations to search in when looking up resources 054 * @return the resolved public URL path; or an empty {@code Mono} if unresolved 055 */ 056 Mono<String> resolveUrlPath(String resourcePath, List<? extends Resource> locations); 057 058}