Add defaultApiVersion to RestClient and WebClient

Closes gh-34857

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClient.java

@@ -94,6 +94,8 @@ final class DefaultWebClient implements WebClient {
 
 	private final @Nullable MultiValueMap<String, String> defaultCookies;
 
+	private final @Nullable Object defaultApiVersion;
+
 	private final @Nullable ApiVersionInserter apiVersionInserter;
 
 	private final @Nullable Consumer<RequestHeadersSpec<?>> defaultRequest;
@@ -110,7 +112,7 @@ final class DefaultWebClient implements WebClient {
 	DefaultWebClient(ExchangeFunction exchangeFunction, @Nullable ExchangeFilterFunction filterFunctions,
 			UriBuilderFactory uriBuilderFactory, @Nullable HttpHeaders defaultHeaders,
 			@Nullable MultiValueMap<String, String> defaultCookies,
-			@Nullable ApiVersionInserter apiVersionInserter,
+			@Nullable Object defaultApiVersion, @Nullable ApiVersionInserter apiVersionInserter,
 			@Nullable Consumer<RequestHeadersSpec<?>> defaultRequest,
 			@Nullable Map<Predicate<HttpStatusCode>, Function<ClientResponse, Mono<? extends Throwable>>> statusHandlerMap,
 			ObservationRegistry observationRegistry, @Nullable ClientRequestObservationConvention observationConvention,
@@ -121,6 +123,7 @@ final class DefaultWebClient implements WebClient {
 		this.uriBuilderFactory = uriBuilderFactory;
 		this.defaultHeaders = defaultHeaders;
 		this.defaultCookies = defaultCookies;
+		this.defaultApiVersion = defaultApiVersion;
 		this.apiVersionInserter = apiVersionInserter;
 		this.defaultRequest = defaultRequest;
 		this.defaultStatusHandlers = initStatusHandlers(statusHandlerMap);
@@ -491,13 +494,18 @@ final class DefaultWebClient implements WebClient {
 
 		private URI initUri() {
 			URI uriToUse = (this.uri != null ? this.uri : uriBuilderFactory.expand(""));
-			if (this.apiVersion != null) {
+			Object version = getApiVersionOrDefault();
+			if (version != null) {
 				Assert.state(apiVersionInserter != null, "No ApiVersionInserter configured");
-				uriToUse = apiVersionInserter.insertVersion(this.apiVersion, uriToUse);
+				uriToUse = apiVersionInserter.insertVersion(version, uriToUse);
 			}
 			return uriToUse;
 		}
 
+		private @Nullable Object getApiVersionOrDefault() {
+			return (this.apiVersion != null ? this.apiVersion : DefaultWebClient.this.defaultApiVersion);
+		}
+
 		private void initHeaders(HttpHeaders out) {
 			if (defaultHeaders != null && !defaultHeaders.isEmpty()) {
 				out.putAll(defaultHeaders);
@@ -505,9 +513,10 @@ final class DefaultWebClient implements WebClient {
 			if (this.headers != null && !this.headers.isEmpty()) {
 				out.putAll(this.headers);
 			}
-			if (this.apiVersion != null) {
+			Object version = getApiVersionOrDefault();
+			if (version != null) {
 				Assert.state(apiVersionInserter != null, "No ApiVersionInserter configured");
-				apiVersionInserter.insertVersion(this.apiVersion, out);
+				apiVersionInserter.insertVersion(version, out);
 			}
 		}
 

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java

@@ -81,6 +81,8 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 
 	private @Nullable MultiValueMap<String, String> defaultCookies;
 
+	private @Nullable Object defaultApiVersion;
+
 	private @Nullable ApiVersionInserter apiVersionInserter;
 
 	private @Nullable Consumer<WebClient.RequestHeadersSpec<?>> defaultRequest;
@@ -122,6 +124,8 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 		}
 
 		this.defaultCookies = (other.defaultCookies != null ? new LinkedMultiValueMap<>(other.defaultCookies) : null);
+
+		this.defaultApiVersion = other.defaultApiVersion;
 		this.apiVersionInserter = other.apiVersionInserter;
 
 		this.defaultRequest = other.defaultRequest;
@@ -194,6 +198,11 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 		return this.defaultCookies;
 	}
 
+	@Override
+	public WebClient.Builder defaultApiVersion(Object version) {
+		this.defaultApiVersion = version;
+		return this;
+	}
 
 	@Override
 	public WebClient.Builder apiVersionInserter(ApiVersionInserter apiVersionInserter) {
@@ -308,7 +317,7 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 		return new DefaultWebClient(
 				exchange, filterFunctions,
 				initUriBuilderFactory(), defaultHeaders, defaultCookies,
-				this.apiVersionInserter,
+				this.defaultApiVersion, this.apiVersionInserter,
 				this.defaultRequest,
 				this.statusHandlers,
 				this.observationRegistry, this.observationConvention,

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/WebClient.java

@@ -252,6 +252,15 @@ public interface WebClient {
 		 */
 		Builder defaultCookies(Consumer<MultiValueMap<String, String>> cookiesConsumer);
 
+		/**
+		 * Global option to specify an API version to add to every request,
+		 * if not already set.
+		 * @param version the version to use
+		 * @return this builder
+		 * @since 7.0
+		 */
+		Builder defaultApiVersion(Object version);
+
 		/**
 		 * Configure an {@link ApiVersionInserter} to abstract how an API version
 		 * specified via {@link RequestHeadersSpec#apiVersion(Object)}