Add support for customizing WebJars resource handler path pattern

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/WebFluxAutoConfiguration.java

@@ -189,8 +189,9 @@ public void addResourceHandlers(ResourceHandlerRegistry registry) {
 				logger.debug("Default resource handling disabled");
 				return;
 			}
-			if (!registry.hasMappingForPattern("/webjars/**")) {
-				ResourceHandlerRegistration registration = registry.addResourceHandler("/webjars/**")
+			String webjarsPathPattern = this.webFluxProperties.getWebjarsPathPattern();
+			if (!registry.hasMappingForPattern(webjarsPathPattern)) {
+				ResourceHandlerRegistration registration = registry.addResourceHandler(webjarsPathPattern)
 						.addResourceLocations("classpath:/META-INF/resources/webjars/");
 				configureResourceCaching(registration);
 				customizeResourceHandlerRegistration(registration);

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/WebFluxProperties.java

@@ -23,6 +23,7 @@
  * {@link ConfigurationProperties properties} for Spring WebFlux.
  *
  * @author Brian Clozel
+ * @author Vedran Pavic
  * @since 2.0.0
  */
 @ConfigurationProperties(prefix = "spring.webflux")
@@ -40,6 +41,11 @@ public class WebFluxProperties {
 	 */
 	private String staticPathPattern = "/**";
 
+	/**
+	 * Path pattern used for WebJar assets.
+	 */
+	private String webjarsPathPattern = "/webjars/**";
+
 	public String getBasePath() {
 		return this.basePath;
 	}
@@ -76,6 +82,14 @@ public void setStaticPathPattern(String staticPathPattern) {
 		this.staticPathPattern = staticPathPattern;
 	}
 
+	public String getWebjarsPathPattern() {
+		return this.webjarsPathPattern;
+	}
+
+	public void setWebjarsPathPattern(String webjarsPathPattern) {
+		this.webjarsPathPattern = webjarsPathPattern;
+	}
+
 	public static class Format {
 
 		/**

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration.java

@@ -329,7 +329,8 @@ public void addResourceHandlers(ResourceHandlerRegistry registry) {
 				logger.debug("Default resource handling disabled");
 				return;
 			}
-			addResourceHandler(registry, "/webjars/**", "classpath:/META-INF/resources/webjars/");
+			addResourceHandler(registry, this.mvcProperties.getWebjarsPathPattern(),
+					"classpath:/META-INF/resources/webjars/");
 			addResourceHandler(registry, this.mvcProperties.getStaticPathPattern(), (registration) -> {
 				registration.addResourceLocations(this.resourceProperties.getStaticLocations());
 				if (this.servletContext != null) {

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -35,6 +35,7 @@
  * @author Stephane Nicoll
  * @author Eddú Meléndez
  * @author Brian Clozel
+ * @author Vedran Pavic
  * @since 2.0.0
  */
 @ConfigurationProperties(prefix = "spring.mvc")
@@ -91,6 +92,11 @@ public class WebMvcProperties {
 	 */
 	private String staticPathPattern = "/**";
 
+	/**
+	 * Path pattern used for WebJar assets.
+	 */
+	private String webjarsPathPattern = "/webjars/**";
+
 	private final Async async = new Async();
 
 	private final Servlet servlet = new Servlet();
@@ -188,6 +194,14 @@ public void setStaticPathPattern(String staticPathPattern) {
 		this.staticPathPattern = staticPathPattern;
 	}
 
+	public String getWebjarsPathPattern() {
+		return this.webjarsPathPattern;
+	}
+
+	public void setWebjarsPathPattern(String webjarsPathPattern) {
+		this.webjarsPathPattern = webjarsPathPattern;
+	}
+
 	public Async getAsync() {
 		return this.async;
 	}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/reactive/WebFluxAutoConfigurationTests.java

@@ -109,6 +109,7 @@
  * @author Brian Clozel
  * @author Andy Wilkinson
  * @author Artsiom Yudovin
+ * @author Vedran Pavic
  */
 class WebFluxAutoConfigurationTests {
 
@@ -186,6 +187,18 @@ void shouldMapResourcesToCustomPath() {
 		});
 	}
 
+	@Test
+	void shouldMapWebjarsToCustomPath() {
+		this.contextRunner.withPropertyValues("spring.webflux.webjars-path-pattern:/assets/**").run((context) -> {
+			SimpleUrlHandlerMapping hm = context.getBean("resourceHandlerMapping", SimpleUrlHandlerMapping.class);
+			assertThat(hm.getUrlMap().get("/assets/**")).isInstanceOf(ResourceWebHandler.class);
+			ResourceWebHandler webjarsHandler = (ResourceWebHandler) hm.getUrlMap().get("/assets/**");
+			assertThat(webjarsHandler.getLocations()).hasSize(1);
+			assertThat(webjarsHandler.getLocations().get(0))
+					.isEqualTo(new ClassPathResource("/META-INF/resources/webjars/"));
+		});
+	}
+
 	@Test
 	void shouldNotMapResourcesWhenDisabled() {
 		this.contextRunner.withPropertyValues("spring.web.resources.add-mappings:false")

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfigurationTests.java

@@ -146,6 +146,7 @@
  * @author Kristine Jetzke
  * @author Artsiom Yudovin
  * @author Scott Frederick
+ * @author Vedran Pavic
  */
 class WebMvcAutoConfigurationTests {
 
@@ -195,6 +196,17 @@ void customResourceHandlerMapping() {
 		});
 	}
 
+	@Test
+	void customWebjarsHandlerMapping() {
+		this.contextRunner.withPropertyValues("spring.mvc.webjars-path-pattern:/assets/**").run((context) -> {
+			Map<String, List<Resource>> locations = getResourceMappingLocations(context);
+			assertThat(locations.get("/assets/**")).hasSize(1);
+			assertThat(locations.get("/assets/**").get(0))
+					.isEqualTo(new ClassPathResource("/META-INF/resources/webjars/"));
+			assertThat(getResourceResolvers(context, "/assets/**")).hasSize(1);
+		});
+	}
+
 	@Test
 	void resourceHandlerMappingOverrideWebjars() {
 		this.contextRunner.withUserConfiguration(WebJars.class).run((context) -> {

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web/reactive.adoc

@@ -84,7 +84,8 @@ If you do so, the default welcome page detection switches to your custom locatio
 So, if there is an `index.html` in any of your locations on startup, it is the home page of the application.
 
 In addition to the "`standard`" static resource locations listed earlier, a special case is made for https://www.webjars.org/[Webjars content].
-Any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format.
+By default, any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format.
+The path can be customized with the configprop:spring.webflux.webjars-path-pattern[] property.
 
 TIP: Spring WebFlux applications do not strictly depend on the servlet API, so they cannot be deployed as war files and do not use the `src/main/webapp` directory.
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web/servlet.adoc

@@ -104,7 +104,8 @@ You can also customize the static resource locations by using the configprop:spr
 The root servlet context path, `"/"`, is automatically added as a location as well.
 
 In addition to the "`standard`" static resource locations mentioned earlier, a special case is made for https://www.webjars.org/[Webjars content].
-Any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format.
+By default, any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format.
+The path can be customized with the configprop:spring.mvc.webjars-path-pattern[] property.
 
 TIP: Do not use the `src/main/webapp` directory if your application is packaged as a jar.
 Although this directory is a common standard, it works *only* with war packaging, and it is silently ignored by most build tools if you generate a jar.