Resolve placeholders in HttpExchange#url

Closes gh-28492

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceMethod.java

@@ -42,6 +42,7 @@
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
+import org.springframework.util.StringValueResolver;
 import org.springframework.web.service.annotation.HttpExchange;
 
 /**
@@ -67,13 +68,13 @@ final class HttpServiceMethod {
 
 	HttpServiceMethod(
 			Method method, Class<?> containingClass, List<HttpServiceArgumentResolver> argumentResolvers,
-			HttpClientAdapter client, ReactiveAdapterRegistry reactiveRegistry,
-			Duration blockTimeout) {
+			HttpClientAdapter client, @Nullable StringValueResolver embeddedValueResolver,
+			ReactiveAdapterRegistry reactiveRegistry, Duration blockTimeout) {
 
 		this.method = method;
 		this.parameters = initMethodParameters(method);
 		this.argumentResolvers = argumentResolvers;
-		this.requestValuesInitializer = HttpRequestValuesInitializer.create(method, containingClass);
+		this.requestValuesInitializer = HttpRequestValuesInitializer.create(method, containingClass, embeddedValueResolver);
 		this.responseFunction = ResponseFunction.create(client, method, reactiveRegistry, blockTimeout);
 	}
 
@@ -161,15 +162,16 @@ public HttpRequestValues.Builder initializeRequestValuesBuilder() {
 		/**
 		 * Introspect the method and create the request factory for it.
 		 */
-		public static HttpRequestValuesInitializer create(Method method, Class<?> containingClass) {
+		public static HttpRequestValuesInitializer create(
+				Method method, Class<?> containingClass, @Nullable StringValueResolver embeddedValueResolver) {
 
 			HttpExchange annot1 = AnnotatedElementUtils.findMergedAnnotation(containingClass, HttpExchange.class);
 			HttpExchange annot2 = AnnotatedElementUtils.findMergedAnnotation(method, HttpExchange.class);
 
 			Assert.notNull(annot2, "Expected HttpRequest annotation");
 
 			HttpMethod httpMethod = initHttpMethod(annot1, annot2);
-			String url = initUrl(annot1, annot2);
+			String url = initUrl(annot1, annot2, embeddedValueResolver);
 			MediaType contentType = initContentType(annot1, annot2);
 			List<MediaType> acceptableMediaTypes = initAccept(annot1, annot2);
 
@@ -194,11 +196,17 @@ private static HttpMethod initHttpMethod(@Nullable HttpExchange typeAnnot, HttpE
 		}
 
 		@Nullable
-		private static String initUrl(@Nullable HttpExchange typeAnnot, HttpExchange annot) {
+		private static String initUrl(
+				@Nullable HttpExchange typeAnnot, HttpExchange annot, @Nullable StringValueResolver embeddedValueResolver) {
 
 			String url1 = (typeAnnot != null ? typeAnnot.url() : null);
 			String url2 = annot.url();
 
+			if (embeddedValueResolver != null) {
+				url1 = (url1 != null ? embeddedValueResolver.resolveStringValue(url1) : null);
+				url2 = embeddedValueResolver.resolveStringValue(url2);
+			}
+
 			boolean hasUrl1 = StringUtils.hasText(url1);
 			boolean hasUrl2 = StringUtils.hasText(url2);
 

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceProxyFactory.java

@@ -35,6 +35,7 @@
 import org.springframework.format.support.DefaultFormattingConversionService;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.StringValueResolver;
 import org.springframework.web.service.annotation.HttpExchange;
 
 /**
@@ -50,17 +51,22 @@ public final class HttpServiceProxyFactory {
 
 	private final List<HttpServiceArgumentResolver> argumentResolvers;
 
+	@Nullable
+	private final StringValueResolver embeddedValueResolver;
+
 	private final ReactiveAdapterRegistry reactiveAdapterRegistry;
 
 	private final Duration blockTimeout;
 
 
 	private HttpServiceProxyFactory(
 			HttpClientAdapter clientAdapter, List<HttpServiceArgumentResolver> argumentResolvers,
-			ReactiveAdapterRegistry reactiveAdapterRegistry, Duration blockTimeout) {
+			@Nullable StringValueResolver embeddedValueResolver, ReactiveAdapterRegistry reactiveAdapterRegistry,
+			Duration blockTimeout) {
 
 		this.clientAdapter = clientAdapter;
 		this.argumentResolvers = argumentResolvers;
+		this.embeddedValueResolver = embeddedValueResolver;
 		this.reactiveAdapterRegistry = reactiveAdapterRegistry;
 		this.blockTimeout = blockTimeout;
 	}
@@ -80,8 +86,8 @@ public <S> S createClient(Class<S> serviceType) {
 						.stream()
 						.map(method ->
 								new HttpServiceMethod(
-										method, serviceType, this.argumentResolvers,
-										this.clientAdapter, this.reactiveAdapterRegistry, this.blockTimeout))
+										method, serviceType, this.argumentResolvers, this.clientAdapter,
+										this.embeddedValueResolver, this.reactiveAdapterRegistry, this.blockTimeout))
 						.toList();
 
 		return ProxyFactory.getProxy(serviceType, new HttpServiceMethodInterceptor(methods));
@@ -114,6 +120,9 @@ public final static class Builder {
 		@Nullable
 		private ConversionService conversionService;
 
+		@Nullable
+		private StringValueResolver embeddedValueResolver;
+
 		private ReactiveAdapterRegistry reactiveAdapterRegistry = ReactiveAdapterRegistry.getSharedInstance();
 
 		private Duration blockTimeout = Duration.ofSeconds(5);
@@ -144,6 +153,18 @@ public Builder setConversionService(ConversionService conversionService) {
 			return this;
 		}
 
+		/**
+		 * Set the StringValueResolver to use for resolving placeholders and
+		 * expressions in {@link HttpExchange#url()}.
+		 * @param embeddedValueResolver the resolver to use
+		 * @return the same builder instance
+		 * @see org.springframework.context.EmbeddedValueResolverAware
+		 */
+		public Builder setEmbeddedValueResolver(@Nullable StringValueResolver embeddedValueResolver) {
+			this.embeddedValueResolver = embeddedValueResolver;
+			return this;
+		}
+
 		/**
 		 * Set the {@link ReactiveAdapterRegistry} to use to support different
 		 * asynchronous types for HTTP service method return values.
@@ -176,7 +197,8 @@ public HttpServiceProxyFactory build() {
 			List<HttpServiceArgumentResolver> resolvers = initArgumentResolvers(conversionService);
 
 			return new HttpServiceProxyFactory(
-					this.clientAdapter, resolvers, this.reactiveAdapterRegistry, this.blockTimeout);
+					this.clientAdapter, resolvers, this.embeddedValueResolver, this.reactiveAdapterRegistry,
+					this.blockTimeout);
 		}
 
 		private ConversionService initConversionService() {

spring-web/src/test/java/org/springframework/web/service/invoker/HttpServiceMethodTests.java

@@ -168,7 +168,11 @@ void methodAnnotatedService() {
 	@Test
 	void typeAndMethodAnnotatedService() {
 
-		MethodLevelAnnotatedService service = this.proxyFactory.createClient(TypeAndMethodLevelAnnotatedService.class);
+		HttpServiceProxyFactory proxyFactory = HttpServiceProxyFactory.builder(this.clientAdapter)
+				.setEmbeddedValueResolver(value -> (value.equals("${baseUrl}") ? "/base" : value))
+				.build();
+
+		MethodLevelAnnotatedService service = proxyFactory.createClient(TypeAndMethodLevelAnnotatedService.class);
 
 		service.performGet();
 
@@ -281,7 +285,7 @@ private interface MethodLevelAnnotatedService {
 
 
 	@SuppressWarnings("unused")
-	@HttpExchange(url = "/base", contentType = APPLICATION_CBOR_VALUE, accept = APPLICATION_CBOR_VALUE)
+	@HttpExchange(url = "${baseUrl}", contentType = APPLICATION_CBOR_VALUE, accept = APPLICATION_CBOR_VALUE)
 	private interface TypeAndMethodLevelAnnotatedService extends MethodLevelAnnotatedService {
 	}