Improve error handling

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/interceptor/SearchPreferHandlingInterceptor.java

@@ -82,6 +82,12 @@ public class SearchPreferHandlingInterceptor {
 			return;
 		}
 
+		String resourceName = theRequestDetails.getResourceName();
+		if (!theRequestDetails.getFhirContext().getResourceTypes().contains(resourceName)) {
+			// This is an error. Let the server handle it normally.
+			return;
+		}
+
 		String preferHeader = theRequestDetails.getHeader(Constants.HEADER_PREFER);
 		PreferHandlingEnum handling = null;
 		if (isNotBlank(preferHeader)) {

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/provider/ServerCapabilityStatementProvider.java

@@ -385,6 +385,7 @@ public class ServerCapabilityStatementProvider implements IServerConformanceProv
 			List<IBaseResource> allStructureDefinitions = myValidationSupport.fetchAllNonBaseStructureDefinitions();
 			if (allStructureDefinitions != null) {
 				for (IBaseResource next : allStructureDefinitions) {
+					String id = next.getIdElement().getValue();
 					String kind = terser.getSinglePrimitiveValueOrNull(next, "kind");
 					String url = terser.getSinglePrimitiveValueOrNull(next, "url");
 					String baseDefinition = defaultString(terser.getSinglePrimitiveValueOrNull(next, "baseDefinition"));
@@ -397,7 +398,12 @@ public class ServerCapabilityStatementProvider implements IServerConformanceProv
 
 						String resourceType = terser.getSinglePrimitiveValueOrNull(next, "snapshot.element.path");
 						if (isBlank(resourceType)) {
+							try {
 								next = myValidationSupport.generateSnapshot(new ValidationSupportContext(myValidationSupport), next, null, null, null);
+							} catch (Exception e) {
+								ourLog.warn("Failure while generating snapshot for StructureDefinition with URL[{}] ID[{}]", url, id, e);
+								continue;
+							}
 							if (next != null) {
 								resourceType = terser.getSinglePrimitiveValueOrNull(next, "snapshot.element.path");
 							}

hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/rest/server/SearchPreferHandlingInterceptorTest.java

@@ -14,6 +14,11 @@ import ca.uhn.fhir.rest.param.TokenAndListParam;
 import ca.uhn.fhir.rest.server.exceptions.InvalidRequestException;
 import ca.uhn.fhir.rest.server.interceptor.SearchPreferHandlingInterceptor;
 import ca.uhn.fhir.test.utilities.server.RestfulServerExtension;
+import org.apache.commons.io.IOUtils;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 import org.hl7.fhir.r4.model.Bundle;
 import org.hl7.fhir.r4.model.HumanName;
@@ -22,6 +27,8 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -67,6 +74,17 @@ public class SearchPreferHandlingInterceptorTest {
 
 	}
 
+	@Test
+	public void testSearchWithUnknownResourceType() throws IOException {
+		try (CloseableHttpClient client = HttpClientBuilder.create().build()) {
+			try (CloseableHttpResponse result = client.execute(new HttpGet("http://localhost:" + myPort + "/BadResource?foo=bar"))) {
+				assertEquals(404, result.getStatusLine().getStatusCode());
+				String response = IOUtils.toString(result.getEntity().getContent(), StandardCharsets.UTF_8);
+				assertThat(response, containsString("Unknown resource type 'BadResource' - Server knows how to handle: [Patient, OperationDefinition]"));
+			}
+		}
+	}
+
 	@Test
 	public void testSearchWithInvalidParam_StrictHeader() {
 		try {