PreMarching filter errors should be filtered as ordinary request filters

Author: dstepanov

http-server-tck/src/main/java/io/micronaut/http/server/tck/tests/filter/ResponseFilterOnPreMatchExceptionHandlerTest.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2017-2023 original authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micronaut.http.server.tck.tests.filter;
+
+import io.micronaut.context.annotation.Requires;
+import io.micronaut.http.HttpRequest;
+import io.micronaut.http.HttpResponse;
+import io.micronaut.http.HttpStatus;
+import io.micronaut.http.MediaType;
+import io.micronaut.http.MutableHttpRequest;
+import io.micronaut.http.MutableHttpResponse;
+import io.micronaut.http.annotation.Controller;
+import io.micronaut.http.annotation.Get;
+import io.micronaut.http.annotation.Produces;
+import io.micronaut.http.annotation.RequestFilter;
+import io.micronaut.http.annotation.ResponseFilter;
+import io.micronaut.http.annotation.ServerFilter;
+import io.micronaut.http.server.annotation.PreMatching;
+import io.micronaut.http.server.exceptions.ExceptionHandler;
+import io.micronaut.http.tck.AssertionUtils;
+import io.micronaut.http.tck.HttpResponseAssertion;
+import io.micronaut.http.tck.TestScenario;
+import jakarta.inject.Singleton;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+
+import static io.micronaut.http.annotation.Filter.MATCH_ALL_PATTERN;
+
+@SuppressWarnings({
+    "java:S5960", // We're allowed assertions, as these are used in tests only
+    "checkstyle:MissingJavadocType",
+    "checkstyle:DesignForExtension"
+})
+public class ResponseFilterOnPreMatchExceptionHandlerTest {
+    private static final String SPEC_NAME = "ResponseFilterOnPreMatchExceptionHandlerTest";
+
+    @Test
+    public void exceptionHandlerTest() throws IOException {
+        TestScenario.builder()
+            .specName(SPEC_NAME)
+            .request(HttpRequest.GET("/foo"))
+            .assertion((server, request) -> AssertionUtils.assertDoesNotThrow(server, request, HttpResponseAssertion.builder()
+                .status(HttpStatus.OK)
+                .body("EXCEPTION MAPPER RESPONSE FILTER")
+                .build()))
+            .run();
+    }
+
+    static class FooException extends RuntimeException {
+
+    }
+
+    @ServerFilter(MATCH_ALL_PATTERN)
+    @Requires(property = "spec.name", value = SPEC_NAME)
+    static class ErrorThrowingFilter {
+        @PreMatching
+        @RequestFilter
+        public void onPreMatching(MutableHttpRequest<?> request) {
+            throw new FooException();
+        }
+
+        @ResponseFilter
+        public void onResponse(MutableHttpResponse<?> response) {
+            response.body(response.getBody(String.class).get() + " RESPONSE FILTER");
+        }
+    }
+
+    @Requires(property = "spec.name", value = SPEC_NAME)
+    @Controller("/foo")
+    static class FooController {
+        @Produces(MediaType.TEXT_PLAIN)
+        @Get
+        String index() {
+            return "Hello World";
+        }
+    }
+
+    @Requires(property = "spec.name", value = SPEC_NAME)
+    @Singleton
+    static class FooExceptionHandler implements ExceptionHandler<FooException, HttpResponse<?>> {
+
+        @Override
+        public HttpResponse<?> handle(HttpRequest request, FooException exception) {
+            return HttpResponse.ok("EXCEPTION MAPPER");
+        }
+    }
+}

http/src/main/java/io/micronaut/http/filter/FilterRunner.java

@@ -234,7 +234,8 @@ public final ExecutionFlow<HttpResponse<?>> run(HttpRequest<?> request,
             } else {
                 // Pre-matching filters plus route match resolver
                 var f = new RouteMatchResolverHttpFilter();
-                filtersToRun.add(f);
+                filtersToRun.add(0, f); // Response filter to resolve filters on error
+                filtersToRun.add(f); // Request filter to resolve filters after preMatch filters
                 iterator = filtersToRun.listIterator();
                 f.filterIterator = iterator;
             }
@@ -396,33 +397,80 @@ private ExecutionFlow<FilterContext> processFailureFilterException(FilterContext
     final class RouteMatchResolverHttpFilter implements InternalHttpFilter {
 
         private ListIterator<InternalHttpFilter> filterIterator;
+        private boolean executed = false;
+
+        @Override
+        public boolean isFiltersResponse() {
+            return true;
+        }
 
         @Override
         public boolean isFiltersRequest() {
             return true;
         }
 
+        @Override
+        public ExecutionFlow<FilterContext> processResponseFilter(FilterContext context, Throwable exceptionToFilter) {
+            if (!executed) {
+                cleanupAllNext();
+                addFoundFilters(context.request());
+                moveIteratorToEnd();
+                return ExecutionFlow.just(context);
+            }
+            return ExecutionFlow.just(context);
+        }
+
         @Override
         public ExecutionFlow<FilterContext> processRequestFilter(FilterContext context) {
+            if (filterIterator.nextIndex() == 1) {
+                return ExecutionFlow.just(context);
+            }
+            executed = true;
             HttpRequest<?> request = context.request();
             try {
                 doRouteMatch(request);
                 return ExecutionFlow.just(context);
             } catch (Throwable throwable) {
                 return processFailurePropagateException(throwable, context);
             } finally {
+                cleanupAllPrevious();
+                addFoundFilters(request);
+                moveIteratorToBeginning();
+            }
+        }
+
+        private void moveIteratorToBeginning() {
+            while (filterIterator.hasPrevious()) {
+                filterIterator.previous();
+            }
+        }
+
+        private void moveIteratorToEnd() {
+            while (filterIterator.hasNext()) {
+                filterIterator.next();
+            }
+        }
+
+        private void addFoundFilters(HttpRequest<?> request) {
+            List<InternalHttpFilter> postFilters = findInternalFiltersAfterRouteMatch(request);
+            for (InternalHttpFilter postFilter : postFilters) {
+                filterIterator.add(postFilter);
+            }
+        }
+
+        private void cleanupAllNext() {
+            filterIterator.remove();
+            while (filterIterator.hasNext()) {
+                filterIterator.next();
+                filterIterator.remove();
+            }
+        }
+
+        private void cleanupAllPrevious() {
+            filterIterator.remove();
+            while (filterIterator.hasPrevious()) {
+                filterIterator.previous();
                 filterIterator.remove();
-                while (filterIterator.hasPrevious()) {
-                    filterIterator.previous();
-                    filterIterator.remove();
-                }
-                List<InternalHttpFilter> postFilters = findInternalFiltersAfterRouteMatch(request);
-                for (InternalHttpFilter postFilter : postFilters) {
-                    filterIterator.add(postFilter);
-                }
-                while (filterIterator.hasPrevious()) {
-                    filterIterator.previous();
-                }
             }
         }
     }