Add possibility for custom MimeMappings

Add a new property called 'mime-mappings' under the 'server' property.
This is a key-value-map, which is added to the default MimeMappings.

See gh-39430

Author: BenchmarkingBuffalo

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

@@ -37,6 +37,7 @@
 import org.springframework.boot.web.server.Compression;
 import org.springframework.boot.web.server.Cookie;
 import org.springframework.boot.web.server.Http2;
+import org.springframework.boot.web.server.MimeMappings;
 import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.servlet.server.Encoding;
@@ -71,6 +72,7 @@
  * @author Parviz Rozikov
  * @author Florian Storz
  * @author Michael Weidmann
+ * @author Lasse Wulff
  * @since 1.0.0
  */
 @ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
@@ -115,6 +117,8 @@ public class ServerProperties {
 	@NestedConfigurationProperty
 	private final Compression compression = new Compression();
 
+	private final MimeMappings mimeMappings = MimeMappings.lazyCopy(MimeMappings.DEFAULT);
+
 	@NestedConfigurationProperty
 	private final Http2 http2 = new Http2();
 
@@ -186,6 +190,14 @@ public Compression getCompression() {
 		return this.compression;
 	}
 
+	public MimeMappings getMimeMappings() {
+		return this.mimeMappings;
+	}
+
+	public void setMimeMappings(Map<String, String> customMappings) {
+		customMappings.forEach(this.mimeMappings::add);
+	}
+
 	public Http2 getHttp2() {
 		return this.http2;
 	}

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

@@ -38,6 +38,7 @@
  * @author Olivier Lamy
  * @author Yunkun Huang
  * @author Scott Frederick
+ * @author Lasse Wulff
  * @since 2.0.0
  */
 public class ServletWebServerFactoryCustomizer
@@ -94,6 +95,7 @@ public void customize(ConfigurableServletWebServerFactory factory) {
 		map.from(() -> this.cookieSameSiteSuppliers)
 			.whenNot(CollectionUtils::isEmpty)
 			.to(factory::setCookieSameSiteSuppliers);
+		map.from(this.serverProperties::getMimeMappings).to(factory::setMimeMappings);
 		this.webListenerRegistrars.forEach((registrar) -> registrar.register(factory));
 	}
 

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

@@ -46,6 +46,8 @@
 import org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory;
 import org.springframework.boot.web.embedded.jetty.JettyWebServer;
 import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
+import org.springframework.boot.web.server.MimeMappings;
+import org.springframework.boot.web.server.MimeMappings.Mapping;
 import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.util.unit.DataSize;
 
@@ -66,6 +68,7 @@
  * @author Rafiullah Hamedy
  * @author Chris Bono
  * @author Parviz Rozikov
+ * @author Lasse Wulff
  */
 @DirtiesUrlFactories
 class ServerPropertiesTests {
@@ -182,6 +185,21 @@ void testContextPathWithLeadingAndTrailingWhitespaceAndContextWithSpace() {
 		assertThat(this.properties.getServlet().getContextPath()).isEqualTo("/assets /copy");
 	}
 
+	@Test
+	void testDefaultMimeMapping() {
+		assertThat(this.properties.getMimeMappings())
+			.containsExactly(MimeMappings.DEFAULT.getAll().toArray(new Mapping[0]));
+	}
+
+	@Test
+	void testCustomizedMimeMapping() {
+		MimeMappings expectedMappings = MimeMappings.lazyCopy(MimeMappings.DEFAULT);
+		expectedMappings.add("mjs", "text/javascript");
+		bind("server.mime-mappings.mjs", "text/javascript");
+		assertThat(this.properties.getMimeMappings())
+			.containsExactly(expectedMappings.getAll().toArray(new Mapping[0]));
+	}
+
 	@Test
 	void testCustomizeUriEncoding() {
 		bind("server.tomcat.uri-encoding", "US-ASCII");

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

@@ -45,6 +45,7 @@
  *
  * @author Brian Clozel
  * @author Yunkun Huang
+ * @author Lasse Wulff
  */
 class ServletWebServerFactoryCustomizerTests {
 
@@ -72,6 +73,13 @@ void testCustomizeDisplayName() {
 		then(factory).should().setDisplayName("TestName");
 	}
 
+	@Test
+	void testCustomMimeMappings() {
+		ConfigurableServletWebServerFactory factory = mock(ConfigurableServletWebServerFactory.class);
+		this.customizer.customize(factory);
+		then(factory).should().setMimeMappings(this.properties.getMimeMappings());
+	}
+
 	@Test
 	void testCustomizeDefaultServlet() {
 		ConfigurableServletWebServerFactory factory = mock(ConfigurableServletWebServerFactory.class);