Polishing external contribution

See gh-29985

Author: poutsma

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultEntityResponseBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -115,6 +115,13 @@ public EntityResponse.Builder<T> headers(HttpHeaders headers) {
 		return this;
 	}
 
+	@Override
+	public EntityResponse.Builder<T> headers(Consumer<HttpHeaders> headersConsumer) {
+		Assert.notNull(headersConsumer, "HeadersConsumer must not be null");
+		headersConsumer.accept(this.headers);
+		return this;
+	}
+
 	@Override
 	public EntityResponse.Builder<T> allow(HttpMethod... allowedMethods) {
 		this.headers.setAllow(new LinkedHashSet<>(Arrays.asList(allowedMethods)));

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultResourceCacheLookupStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -149,6 +149,18 @@ interface Builder<T> {
 		 */
 		Builder<T> headers(HttpHeaders headers);
 
+		/**
+		 * Manipulate this entity's headers with the given consumer. The
+		 * headers provided to the consumer are "live", so that the consumer can be used to
+		 * {@linkplain HttpHeaders#set(String, String) overwrite} existing header values,
+		 * {@linkplain HttpHeaders#remove(Object) remove} values, or use any of the other
+		 * {@link HttpHeaders} methods.
+		 * @param headersConsumer a function that consumes the {@code HttpHeaders}
+		 * @return this builder
+		 * @since 6.1
+		 */
+		Builder<T> headers(Consumer<HttpHeaders> headersConsumer);
+
 		/**
 		 * Set the HTTP status.
 		 * @param status the response status

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/EntityResponse.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -23,11 +23,12 @@
 import java.net.URI;
 import java.net.URL;
 import java.util.Set;
+import java.util.function.BiConsumer;
 
 import reactor.core.publisher.Mono;
 
 import org.springframework.core.io.Resource;
-import org.springframework.http.CacheControl;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.lang.Nullable;
@@ -46,18 +47,13 @@ class ResourceHandlerFunction implements HandlerFunction<ServerResponse> {
 
 
 	private final Resource resource;
-	private final CacheControl cacheControl;
 
-
-	public ResourceHandlerFunction(Resource resource) {
-		this.resource = resource;
-		this.cacheControl = CacheControl.empty();
-	}
+	private final BiConsumer<Resource, HttpHeaders> headersConsumer;
 
 
-	public ResourceHandlerFunction(Resource resource, ResourceCacheLookupStrategy strategy) {
+	public ResourceHandlerFunction(Resource resource, BiConsumer<Resource, HttpHeaders> headersConsumer) {
 		this.resource = resource;
-		this.cacheControl = strategy.lookupCacheControl(resource);
+		this.headersConsumer = headersConsumer;
 	}
 
 
@@ -66,14 +62,14 @@ public Mono<ServerResponse> handle(ServerRequest request) {
 		HttpMethod method = request.method();
 		if (HttpMethod.GET.equals(method)) {
 			return EntityResponse.fromObject(this.resource)
-					.cacheControl(this.cacheControl)
+					.headers(headers -> this.headersConsumer.accept(this.resource, headers))
 					.build()
 					.map(response -> response);
 		}
 		else if (HttpMethod.HEAD.equals(method)) {
 			Resource headResource = new HeadMethodResource(this.resource);
 			return EntityResponse.fromObject(headResource)
-					.cacheControl(this.cacheControl)
+					.headers(headers -> this.headersConsumer.accept(this.resource, headers))
 					.build()
 					.map(response -> response);
 		}

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ResourceCacheLookupStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -19,6 +19,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -30,6 +31,7 @@
 import reactor.core.publisher.Mono;
 
 import org.springframework.core.io.Resource;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.util.Assert;
 
@@ -242,8 +244,10 @@ public RouterFunctions.Builder resources(String pattern, Resource location) {
 	}
 
 	@Override
-	public RouterFunctions.Builder resources(String pattern, Resource location, ResourceCacheLookupStrategy resourceCacheLookupStrategy) {
-		return add(RouterFunctions.resources(pattern,location,resourceCacheLookupStrategy));
+	public RouterFunctions.Builder resources(String pattern, Resource location,
+			BiConsumer<Resource, HttpHeaders> headersConsumer) {
+
+		return add(RouterFunctions.resources(pattern, location, headersConsumer));
 	}
 
 	@Override
@@ -252,8 +256,10 @@ public RouterFunctions.Builder resources(Function<ServerRequest, Mono<Resource>>
 	}
 
 	@Override
-	public RouterFunctions.Builder resources(Function<ServerRequest, Mono<Resource>> lookupFunction, ResourceCacheLookupStrategy resourceCacheLookupStrategy) {
-		return add(RouterFunctions.resources(lookupFunction,resourceCacheLookupStrategy));
+	public RouterFunctions.Builder resources(Function<ServerRequest, Mono<Resource>> lookupFunction,
+			BiConsumer<Resource, HttpHeaders> headersConsumer) {
+
+		return add(RouterFunctions.resources(lookupFunction, headersConsumer));
 	}
 
 	@Override

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ResourceHandlerFunction.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -20,6 +20,7 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -32,6 +33,7 @@
 import reactor.core.publisher.Mono;
 
 import org.springframework.core.io.Resource;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.server.reactive.HttpHandler;
@@ -156,10 +158,26 @@ public static <T extends ServerResponse> RouterFunction<T> nest(
 	 * @see #resourceLookupFunction(String, Resource)
 	 */
 	public static RouterFunction<ServerResponse> resources(String pattern, Resource location) {
-		return resources(resourceLookupFunction(pattern, location), ResourceCacheLookupStrategy.noCaching());
+		return resources(resourceLookupFunction(pattern, location), (resource, httpHeaders) -> {});
 	}
-	public static RouterFunction<ServerResponse> resources(String pattern, Resource location, ResourceCacheLookupStrategy lookupStrategy) {
-		return resources(resourceLookupFunction(pattern, location), lookupStrategy);
+
+	/**
+	 * Route requests that match the given pattern to resources relative to the given root location.
+	 * For instance
+	 * <pre class="code">
+	 * Resource location = new FileSystemResource("public-resources/");
+	 * RouterFunction&lt;ServerResponse&gt; resources = RouterFunctions.resources("/resources/**", location);
+     * </pre>
+	 * @param pattern the pattern to match
+	 * @param location the location directory relative to which resources should be resolved
+	 * @param headersConsumer provides access to the HTTP headers for served resources
+	 * @return a router function that routes to resources
+	 * @since 6.1
+	 * @see #resourceLookupFunction(String, Resource)
+	 */
+	public static RouterFunction<ServerResponse> resources(String pattern, Resource location,
+			BiConsumer<Resource, HttpHeaders> headersConsumer) {
+		return resources(resourceLookupFunction(pattern, location), headersConsumer);
 	}
 
 	/**
@@ -189,10 +207,21 @@ public static Function<ServerRequest, Mono<Resource>> resourceLookupFunction(Str
 	 * @return a router function that routes to resources
 	 */
 	public static RouterFunction<ServerResponse> resources(Function<ServerRequest, Mono<Resource>> lookupFunction) {
-		return new ResourcesRouterFunction(lookupFunction, ResourceCacheLookupStrategy.noCaching());
+		return new ResourcesRouterFunction(lookupFunction, (resource, httpHeaders) -> {});
 	}
-	public static RouterFunction<ServerResponse> resources(Function<ServerRequest, Mono<Resource>> lookupFunction, ResourceCacheLookupStrategy lookupStrategy) {
-		return new ResourcesRouterFunction(lookupFunction, lookupStrategy);
+
+	/**
+	 * Route to resources using the provided lookup function. If the lookup function provides a
+	 * {@link Resource} for the given request, it will be it will be exposed using a
+	 * {@link HandlerFunction} that handles GET, HEAD, and OPTIONS requests.
+	 * @param lookupFunction the function to provide a {@link Resource} given the {@link ServerRequest}
+	 * @param headersConsumer provides access to the HTTP headers for served resources
+	 * @return a router function that routes to resources
+	 * @since 6.1
+	 */
+	public static RouterFunction<ServerResponse> resources(Function<ServerRequest, Mono<Resource>> lookupFunction,
+			BiConsumer<Resource, HttpHeaders> headersConsumer) {
+		return new ResourcesRouterFunction(lookupFunction, headersConsumer);
 	}
 
 	/**
@@ -658,7 +687,21 @@ public interface Builder {
 		 * @return this builder
 		 */
 		Builder resources(String pattern, Resource location);
-		Builder resources(String pattern, Resource location, ResourceCacheLookupStrategy resourceCacheLookupStrategy);
+
+		/**
+		 * Route requests that match the given pattern to resources relative to the given root location.
+		 * For instance
+		 * <pre class="code">
+		 * Resource location = new FileSystemResource("public-resources/");
+		 * RouterFunction&lt;ServerResponse&gt; resources = RouterFunctions.resources("/resources/**", location);
+	     * </pre>
+		 * @param pattern the pattern to match
+		 * @param location the location directory relative to which resources should be resolved
+		 * @param headersConsumer provides access to the HTTP headers for served resources
+		 * @return this builder
+		 * @since 6.1
+		 */
+		Builder resources(String pattern, Resource location, BiConsumer<Resource, HttpHeaders> headersConsumer);
 
 		/**
 		 * Route to resources using the provided lookup function. If the lookup function provides a
@@ -668,7 +711,17 @@ public interface Builder {
 		 * @return this builder
 		 */
 		Builder resources(Function<ServerRequest, Mono<Resource>> lookupFunction);
-		Builder resources(Function<ServerRequest, Mono<Resource>> lookupFunction, ResourceCacheLookupStrategy resourceCacheLookupStrategy);
+
+		/**
+		 * Route to resources using the provided lookup function. If the lookup function provides a
+		 * {@link Resource} for the given request, it will be it will be exposed using a
+		 * {@link HandlerFunction} that handles GET, HEAD, and OPTIONS requests.
+		 * @param lookupFunction the function to provide a {@link Resource} given the {@link ServerRequest}
+		 * @param headersConsumer provides access to the HTTP headers for served resources
+		 * @return this builder
+		 * @since 6.1
+		 */
+		Builder resources(Function<ServerRequest, Mono<Resource>> lookupFunction, BiConsumer<Resource, HttpHeaders> headersConsumer);
 
 		/**
 		 * Route to the supplied router function if the given request predicate applies. This method
@@ -1150,22 +1203,20 @@ private static class ResourcesRouterFunction extends  AbstractRouterFunction<Ser
 
 		private final Function<ServerRequest, Mono<Resource>> lookupFunction;
 
-		private final ResourceCacheLookupStrategy lookupStrategy;
+		private final BiConsumer<Resource, HttpHeaders> headersConsumer;
 
-		public ResourcesRouterFunction(Function<ServerRequest, Mono<Resource>> lookupFunction) {
-			this(lookupFunction, ResourceCacheLookupStrategy.noCaching());
-		}
 
-		public ResourcesRouterFunction(Function<ServerRequest, Mono<Resource>> lookupFunction, ResourceCacheLookupStrategy lookupStrategy) {
+		public ResourcesRouterFunction(Function<ServerRequest, Mono<Resource>> lookupFunction,
+				BiConsumer<Resource, HttpHeaders> headersConsumer) {
 			Assert.notNull(lookupFunction, "Function must not be null");
-			Assert.notNull(lookupStrategy, "Strategy must not be null");
+			Assert.notNull(headersConsumer, "HeadersConsumer must not be null");
 			this.lookupFunction = lookupFunction;
-			this.lookupStrategy = lookupStrategy;
+			this.headersConsumer = headersConsumer;
 		}
 
 		@Override
 		public Mono<HandlerFunction<ServerResponse>> route(ServerRequest request) {
-			return this.lookupFunction.apply(request).map(resource -> new ResourceHandlerFunction(resource, this.lookupStrategy));
+			return this.lookupFunction.apply(request).map(resource -> new ResourceHandlerFunction(resource, this.headersConsumer));
 		}
 
 		@Override

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RouterFunctionBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -47,7 +47,7 @@ public class ResourceHandlerFunctionTests {
 
 	private final Resource resource = new ClassPathResource("response.txt", getClass());
 
-	private final ResourceHandlerFunction handlerFunction = new ResourceHandlerFunction(this.resource);
+	private final ResourceHandlerFunction handlerFunction = new ResourceHandlerFunction(this.resource, (r, h) -> {});
 
 	private ServerResponse.Context context;