Introduce resource_metadata parameter resolver for BearerTokenAuthenticationEntryPoint

oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/web/BearerTokenAuthenticationEntryPoint.java

@@ -18,6 +18,7 @@
 
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.function.Function;
 
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
@@ -51,6 +52,8 @@ public final class BearerTokenAuthenticationEntryPoint implements Authentication
 
 	private String realmName;
 
+	private Function<HttpServletRequest, String> resourceMetadataParameterResolver = BearerTokenAuthenticationEntryPoint::getResourceMetadataParameter;
+
 	/**
 	 * Collect error details from the provided parameters and format according to RFC
 	 * 6750, specifically {@code error}, {@code error_description}, {@code error_uri}, and
@@ -83,7 +86,7 @@ public void commence(HttpServletRequest request, HttpServletResponse response,
 				status = bearerTokenError.getHttpStatus();
 			}
 		}
-		parameters.put("resource_metadata", getResourceMetadataParameter(request));
+		parameters.put("resource_metadata", this.resourceMetadataParameterResolver.apply(request));
 		String wwwAuthenticate = computeWWWAuthenticateHeaderValue(parameters);
 		response.addHeader(HttpHeaders.WWW_AUTHENTICATE, wwwAuthenticate);
 		response.setStatus(status.value());
@@ -97,6 +100,16 @@ public void setRealmName(String realmName) {
 		this.realmName = realmName;
 	}
 
+	/**
+	 * Set the resolver to compute the {@code resource_metadata} parameter from the
+	 * request.
+	 * @param resourceMetadataParameterResolver
+	 */
+	public void setResourceMetadataParameterResolver(
+			Function<HttpServletRequest, String> resourceMetadataParameterResolver) {
+		this.resourceMetadataParameterResolver = resourceMetadataParameterResolver;
+	}
+
 	private static String getResourceMetadataParameter(HttpServletRequest request) {
 		String path = request.getContextPath()
 				+ OAuth2ProtectedResourceMetadataFilter.DEFAULT_OAUTH2_PROTECTED_RESOURCE_METADATA_ENDPOINT_URI;

oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/web/BearerTokenAuthenticationEntryPointTests.java

@@ -77,6 +77,19 @@ public void commenceWhenNoBearerTokenErrorAndContextPathSetThenStatus401AndAuthH
 
 	}
 
+	@Test
+	public void commenceWhenNoBearerTokenErrorAndResourceMetadataResolverSetThenStatus401AndAuthHeaderWithResolvedResourceMetadata() {
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.setAttribute("resource_id", "https://example.com/resource-from-request");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		this.authenticationEntryPoint
+			.setResourceMetadataParameterResolver((req) -> req.getAttribute("resource_id").toString());
+		this.authenticationEntryPoint.commence(request, response, new BadCredentialsException("test"));
+		assertThat(response.getStatus()).isEqualTo(401);
+		assertThat(response.getHeader("WWW-Authenticate"))
+			.isEqualTo("Bearer resource_metadata=\"https://example.com/resource-from-request\"");
+	}
+
 	@Test
 	public void commenceWhenInvalidRequestErrorThenStatus400AndHeaderWithError() throws Exception {
 		MockHttpServletRequest request = new MockHttpServletRequest();