Introduced DispatcherType request matcher

Created a DispatcherTypeRequestMatcher and corresponding methods
for configuring an HttpSecurity object. This enables filtering of
security rules based on the dispatcher type of the incoming servlet
request.

Closes gh-9205

web/src/test/java/org/springframework/security/web/util/matcher/DispatcherTypeRequestMatcherTests.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2002-2020 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.security.web.util.matcher;
+
+import javax.servlet.DispatcherType;
+import javax.servlet.http.HttpServletRequest;
+
+import org.junit.Test;
+
+import org.springframework.http.HttpMethod;
+import org.springframework.mock.web.MockHttpServletRequest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Nick McKinney
+ */
+public class DispatcherTypeRequestMatcherTests {
+
+	@Test
+	public void matches_dispatcher_type() {
+		HttpServletRequest request = mockHttpServletRequest(DispatcherType.ERROR, HttpMethod.GET);
+		DispatcherTypeRequestMatcher matcher = new DispatcherTypeRequestMatcher(DispatcherType.ERROR);
+
+		assertThat(matcher.matches(request)).isTrue();
+	}
+
+	@Test
+	public void matches_dispatcher_type_and_http_method() {
+		HttpServletRequest request = mockHttpServletRequest(DispatcherType.ERROR, HttpMethod.GET);
+		DispatcherTypeRequestMatcher matcher = new DispatcherTypeRequestMatcher(DispatcherType.ERROR, HttpMethod.GET);
+
+		assertThat(matcher.matches(request)).isTrue();
+	}
+
+	@Test
+	public void does_not_match_wrong_type() {
+		HttpServletRequest request = mockHttpServletRequest(DispatcherType.FORWARD, HttpMethod.GET);
+		DispatcherTypeRequestMatcher matcher = new DispatcherTypeRequestMatcher(DispatcherType.ERROR);
+
+		assertThat(matcher.matches(request)).isFalse();
+	}
+
+	@Test
+	public void does_not_match_with_wrong_http_method() {
+		HttpServletRequest request = mockHttpServletRequest(DispatcherType.ERROR, HttpMethod.GET);
+		DispatcherTypeRequestMatcher matcher = new DispatcherTypeRequestMatcher(DispatcherType.ERROR, HttpMethod.POST);
+
+		assertThat(matcher.matches(request)).isFalse();
+	}
+
+	@Test
+	public void null_http_method_matches_any_http_method() {
+		HttpServletRequest request = mockHttpServletRequest(DispatcherType.ERROR, HttpMethod.POST);
+		DispatcherTypeRequestMatcher matcher = new DispatcherTypeRequestMatcher(DispatcherType.ERROR, null);
+
+		assertThat(matcher.matches(request)).isTrue();
+	}
+
+	private HttpServletRequest mockHttpServletRequest(DispatcherType dispatcherType, HttpMethod httpMethod) {
+		MockHttpServletRequest mockHttpServletRequest = new MockHttpServletRequest();
+		mockHttpServletRequest.setDispatcherType(dispatcherType);
+		mockHttpServletRequest.setMethod(httpMethod.name());
+		return mockHttpServletRequest;
+	}
+
+}