Create optimized RequestPredicate for GraphQL endpoints

Prior to this commit, Spring Boot applications would wire the GraphQL
handlers (for various transports and both WebFlux and WebMVC) with
standard `RequestPredicates` chained into a `RouterFunction`.

While this is the expected way for custom application endpoints, stock
predicates are more general purpose and require some overhead when
copying attributes.

This commit introduces custom predicates, optimized for faster and lower
overhead matching. The new `GraphQlRequestPredicates` classes provide
factory methods for HTTP and SSE predicates.

Closes gh-906

spring-graphql/src/main/java/org/springframework/graphql/server/webflux/GraphQlRequestPredicates.java

@@ -0,0 +1,167 @@
+/*
+ * Copyright 2020-2024 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.
+ * 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 org.springframework.graphql.server.webflux;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.server.PathContainer;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.MimeTypeUtils;
+import org.springframework.web.cors.reactive.CorsUtils;
+import org.springframework.web.reactive.function.server.RequestPredicate;
+import org.springframework.web.reactive.function.server.ServerRequest;
+import org.springframework.web.util.pattern.PathPattern;
+import org.springframework.web.util.pattern.PathPatternParser;
+
+/**
+ * {@link RequestPredicate} implementations tailored for GraphQL reactive endpoints.
+ *
+ * @author Brian Clozel
+ * @since 1.3.0
+ */
+public class GraphQlRequestPredicates {
+
+    private static final Log logger = LogFactory.getLog(GraphQlRequestPredicates.class);
+
+    /**
+     * Create a {@link RequestPredicate predicate} that matches GraphQL HTTP requests for the configured path.
+     *
+     * @param path the path on which the GraphQL HTTP endpoint is mapped
+     * @see GraphQlHttpHandler
+     */
+    public static RequestPredicate graphQlHttp(String path) {
+        return new GraphQlHttpRequestPredicate(path, MediaType.APPLICATION_JSON, MediaType.APPLICATION_GRAPHQL_RESPONSE);
+    }
+
+    /**
+     * Create a {@link RequestPredicate predicate} that matches GraphQL SSE over HTTP requests for the configured path.
+     *
+     * @param path the path on which the GraphQL SSE endpoint is mapped
+     * @see GraphQlSseHandler
+     */
+    public static RequestPredicate graphQlSse(String path) {
+        return new GraphQlHttpRequestPredicate(path, MediaType.TEXT_EVENT_STREAM);
+    }
+
+    private static class GraphQlHttpRequestPredicate implements RequestPredicate {
+
+        private final PathPattern pattern;
+
+        private final List<MediaType> acceptedMediaTypes;
+
+
+        GraphQlHttpRequestPredicate(String path, MediaType... accepted) {
+            Assert.notNull(path, "'path' must not be null");
+            Assert.notEmpty(accepted, "'accepted' must not be empty");
+            PathPatternParser parser = PathPatternParser.defaultInstance;
+            path = parser.initFullPathPattern(path);
+            this.pattern = parser.parse(path);
+            this.acceptedMediaTypes = Arrays.asList(accepted);
+        }
+
+        @Override
+        public boolean test(ServerRequest request) {
+            return methodMatch(request, HttpMethod.POST)
+                    && contentTypeMatch(request, MediaType.APPLICATION_JSON)
+                    && acceptMatch(request, this.acceptedMediaTypes)
+                    && pathMatch(request, this.pattern);
+        }
+    }
+
+    private static boolean methodMatch(ServerRequest request, HttpMethod expected) {
+        HttpMethod actual = resolveMethod(request);
+        boolean methodMatch = expected.equals(actual);
+        traceMatch("Method", expected, actual, methodMatch);
+        return methodMatch;
+    }
+
+    private static HttpMethod resolveMethod(ServerRequest request) {
+        if (CorsUtils.isPreFlightRequest(request.exchange().getRequest())) {
+            String accessControlRequestMethod =
+                    request.headers().firstHeader(HttpHeaders.ACCESS_CONTROL_REQUEST_METHOD);
+            if (accessControlRequestMethod != null) {
+                return HttpMethod.valueOf(accessControlRequestMethod);
+            }
+        }
+        return request.method();
+    }
+
+    private static boolean contentTypeMatch(ServerRequest request, MediaType expected) {
+        if (CorsUtils.isPreFlightRequest(request.exchange().getRequest())) {
+            return true;
+        }
+        ServerRequest.Headers headers = request.headers();
+        MediaType actual = headers.contentType().orElse(MediaType.APPLICATION_OCTET_STREAM);
+        boolean contentTypeMatch = expected.includes(actual);
+        traceMatch("Content-Type", expected, actual, contentTypeMatch);
+        return contentTypeMatch;
+    }
+
+    private static boolean acceptMatch(ServerRequest request, List<MediaType> expected) {
+        if (CorsUtils.isPreFlightRequest(request.exchange().getRequest())) {
+            return true;
+        }
+        ServerRequest.Headers headers = request.headers();
+        List<MediaType> acceptedMediaTypes = acceptedMediaTypes(headers);
+        boolean match = false;
+        outer:
+        for (MediaType acceptedMediaType : acceptedMediaTypes) {
+            for (MediaType mediaType : expected) {
+                if (acceptedMediaType.isCompatibleWith(mediaType)) {
+                    match = true;
+                    break outer;
+                }
+            }
+        }
+        traceMatch("Accept", expected, acceptedMediaTypes, match);
+        return match;
+    }
+
+    private static List<MediaType> acceptedMediaTypes(ServerRequest.Headers headers) {
+        List<MediaType> acceptedMediaTypes = headers.accept();
+        if (acceptedMediaTypes.isEmpty()) {
+            acceptedMediaTypes = Collections.singletonList(MediaType.ALL);
+        } else {
+            MimeTypeUtils.sortBySpecificity(acceptedMediaTypes);
+        }
+        return acceptedMediaTypes;
+    }
+
+    private static boolean pathMatch(ServerRequest request, PathPattern pattern) {
+        PathContainer pathContainer = request.requestPath().pathWithinApplication();
+        boolean pathMatch = pattern.matches(pathContainer);
+        traceMatch("Pattern", pattern.getPatternString(), request.path(), pathMatch);
+        return pathMatch;
+    }
+
+    private static void traceMatch(String prefix, Object desired, @Nullable Object actual, boolean match) {
+        if (logger.isTraceEnabled()) {
+            logger.trace(String.format("%s \"%s\" %s against value \"%s\"",
+                    prefix, desired, match ? "matches" : "does not match", actual));
+        }
+    }
+
+}

spring-graphql/src/main/java/org/springframework/graphql/server/webmvc/GraphQlRequestPredicates.java

@@ -0,0 +1,167 @@
+/*
+ * Copyright 2020-2024 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.
+ * 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 org.springframework.graphql.server.webmvc;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.server.PathContainer;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.MimeTypeUtils;
+import org.springframework.web.cors.CorsUtils;
+import org.springframework.web.servlet.function.RequestPredicate;
+import org.springframework.web.servlet.function.ServerRequest;
+import org.springframework.web.util.pattern.PathPattern;
+import org.springframework.web.util.pattern.PathPatternParser;
+
+/**
+ * {@link RequestPredicate} implementations tailored for GraphQL endpoints.
+ *
+ * @author Brian Clozel
+ * @since 1.3.0
+ */
+public class GraphQlRequestPredicates {
+
+    private static final Log logger = LogFactory.getLog(GraphQlRequestPredicates.class);
+
+    /**
+     * Create a {@link RequestPredicate predicate} that matches GraphQL HTTP requests for the configured path.
+     *
+     * @param path the path on which the GraphQL HTTP endpoint is mapped
+     * @see GraphQlHttpHandler
+     */
+    public static RequestPredicate graphQlHttp(String path) {
+        return new GraphQlHttpRequestPredicate(path, MediaType.APPLICATION_JSON, MediaType.APPLICATION_GRAPHQL_RESPONSE);
+    }
+
+    /**
+     * Create a {@link RequestPredicate predicate} that matches GraphQL SSE over HTTP requests for the configured path.
+     *
+     * @param path the path on which the GraphQL SSE endpoint is mapped
+     * @see GraphQlSseHandler
+     */
+    public static RequestPredicate graphQlSse(String path) {
+        return new GraphQlHttpRequestPredicate(path, MediaType.TEXT_EVENT_STREAM);
+    }
+
+    private static class GraphQlHttpRequestPredicate implements RequestPredicate {
+
+        private final PathPattern pattern;
+
+        private final List<MediaType> acceptedMediaTypes;
+
+
+        GraphQlHttpRequestPredicate(String path, MediaType... accepted) {
+            Assert.notNull(path, "'path' must not be null");
+            Assert.notEmpty(accepted, "'accepted' must not be empty");
+            PathPatternParser parser = PathPatternParser.defaultInstance;
+            path = parser.initFullPathPattern(path);
+            this.pattern = parser.parse(path);
+            this.acceptedMediaTypes = Arrays.asList(accepted);
+        }
+
+        @Override
+        public boolean test(ServerRequest request) {
+            return methodMatch(request, HttpMethod.POST)
+                    && contentTypeMatch(request, MediaType.APPLICATION_JSON)
+                    && acceptMatch(request, this.acceptedMediaTypes)
+                    && pathMatch(request, this.pattern);
+        }
+    }
+
+    private static boolean methodMatch(ServerRequest request, HttpMethod expected) {
+        HttpMethod actual = resolveMethod(request);
+        boolean methodMatch = expected.equals(actual);
+        traceMatch("Method", expected, actual, methodMatch);
+        return methodMatch;
+    }
+
+    private static HttpMethod resolveMethod(ServerRequest request) {
+        if (CorsUtils.isPreFlightRequest(request.servletRequest())) {
+            String accessControlRequestMethod =
+                    request.headers().firstHeader(HttpHeaders.ACCESS_CONTROL_REQUEST_METHOD);
+            if (accessControlRequestMethod != null) {
+                return HttpMethod.valueOf(accessControlRequestMethod);
+            }
+        }
+        return request.method();
+    }
+
+    private static boolean contentTypeMatch(ServerRequest request, MediaType expected) {
+        if (CorsUtils.isPreFlightRequest(request.servletRequest())) {
+            return true;
+        }
+        ServerRequest.Headers headers = request.headers();
+        MediaType actual = headers.contentType().orElse(MediaType.APPLICATION_OCTET_STREAM);
+        boolean contentTypeMatch = expected.includes(actual);
+        traceMatch("Content-Type", expected, actual, contentTypeMatch);
+        return contentTypeMatch;
+    }
+
+    private static boolean acceptMatch(ServerRequest request, List<MediaType> expected) {
+        if (CorsUtils.isPreFlightRequest(request.servletRequest())) {
+            return true;
+        }
+        ServerRequest.Headers headers = request.headers();
+        List<MediaType> acceptedMediaTypes = acceptedMediaTypes(headers);
+        boolean match = false;
+        outer:
+        for (MediaType acceptedMediaType : acceptedMediaTypes) {
+            for (MediaType mediaType : expected) {
+                if (acceptedMediaType.isCompatibleWith(mediaType)) {
+                    match = true;
+                    break outer;
+                }
+            }
+        }
+        traceMatch("Accept", expected, acceptedMediaTypes, match);
+        return match;
+    }
+
+    private static List<MediaType> acceptedMediaTypes(ServerRequest.Headers headers) {
+        List<MediaType> acceptedMediaTypes = headers.accept();
+        if (acceptedMediaTypes.isEmpty()) {
+            acceptedMediaTypes = Collections.singletonList(MediaType.ALL);
+        } else {
+            MimeTypeUtils.sortBySpecificity(acceptedMediaTypes);
+        }
+        return acceptedMediaTypes;
+    }
+
+    private static boolean pathMatch(ServerRequest request, PathPattern pattern) {
+        PathContainer pathContainer = request.requestPath().pathWithinApplication();
+        boolean pathMatch = pattern.matches(pathContainer);
+        traceMatch("Pattern", pattern.getPatternString(), request.path(), pathMatch);
+        return pathMatch;
+    }
+
+    private static void traceMatch(String prefix, Object desired, @Nullable Object actual, boolean match) {
+        if (logger.isTraceEnabled()) {
+            logger.trace(String.format("%s \"%s\" %s against value \"%s\"",
+                    prefix, desired, match ? "matches" : "does not match", actual));
+        }
+    }
+
+}