Make Optional Pretty-Printed Metadata

Closes gh-13715

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/OpenSamlMetadataResolver.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.
@@ -72,6 +72,8 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	private Consumer<EntityDescriptorParameters> entityDescriptorCustomizer = (parameters) -> {
 	};
 
+	private boolean usePrettyPrint = true;
+
 	public OpenSamlMetadataResolver() {
 		this.entityDescriptorMarshaller = (EntityDescriptorMarshaller) XMLObjectProviderRegistrySupport
 			.getMarshallerFactory()
@@ -123,6 +125,15 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 		this.entityDescriptorCustomizer = entityDescriptorCustomizer;
 	}
 
+	/**
+	 * Configure whether to pretty-print the metadata XML. This can be helpful when
+	 * signing the metadata payload.
+	 * @since 6.2
+	 **/
+	public void setUsePrettyPrint(boolean usePrettyPrint) {
+		this.usePrettyPrint = usePrettyPrint;
+	}
+
 	private SPSSODescriptor buildSpSsoDescriptor(RelyingPartyRegistration registration) {
 		SPSSODescriptor spSsoDescriptor = build(SPSSODescriptor.DEFAULT_ELEMENT_NAME);
 		spSsoDescriptor.addSupportedProtocol(SAMLConstants.SAML20P_NS);
@@ -204,7 +215,10 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	private String serialize(EntityDescriptor entityDescriptor) {
 		try {
 			Element element = this.entityDescriptorMarshaller.marshall(entityDescriptor);
-			return SerializeSupport.prettyPrintXML(element);
+			if (this.usePrettyPrint) {
+				return SerializeSupport.prettyPrintXML(element);
+			}
+			return SerializeSupport.nodeToString(element);
 		}
 		catch (Exception ex) {
 			throw new Saml2Exception(ex);
@@ -214,7 +228,10 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	private String serialize(EntitiesDescriptor entities) {
 		try {
 			Element element = this.entitiesDescriptorMarshaller.marshall(entities);
-			return SerializeSupport.prettyPrintXML(element);
+			if (this.usePrettyPrint) {
+				return SerializeSupport.prettyPrintXML(element);
+			}
+			return SerializeSupport.nodeToString(element);
 		}
 		catch (Exception ex) {
 			throw new Saml2Exception(ex);