Add predicate to detect requests made for a Cloud Foundry route service. (#241)

See gh-190

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/handler/predicate/CloudFoundryRouteServicePredicateFactory.java

@@ -0,0 +1,38 @@
+package org.springframework.cloud.gateway.handler.predicate;
+
+import java.util.function.Predicate;
+
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * Creates a predicate which indicates if the request is intended for a Cloud Foundry Route Service.
+ * @see <a href="https://docs.cloudfoundry.org/services/route-services.html">Cloud Foundry Route Service documentation</a>.
+ * @author Andrew Fitzgerald
+ */
+public class CloudFoundryRouteServicePredicateFactory extends
+		AbstractRoutePredicateFactory<Object> {
+
+	public static final String X_CF_FORWARDED_URL = "X-CF-Forwarded-Url";
+	public static final String X_CF_PROXY_SIGNATURE = "X-CF-Proxy-Signature";
+	public static final String X_CF_PROXY_METADATA = "X-CF-Proxy-Metadata";
+	private final HeaderRoutePredicateFactory factory = new HeaderRoutePredicateFactory();
+
+	public CloudFoundryRouteServicePredicateFactory() {
+		super(Object.class);
+	}
+
+	@Override
+	public Predicate<ServerWebExchange> apply(
+			Object unused) {
+		return headerPredicate(X_CF_FORWARDED_URL)
+				.and(headerPredicate(X_CF_PROXY_SIGNATURE))
+				.and(headerPredicate(X_CF_PROXY_METADATA));
+	}
+
+	private Predicate<ServerWebExchange> headerPredicate(String header) {
+		HeaderRoutePredicateFactory.Config config = factory.newConfig();
+		config.setHeader(header);
+		config.setRegexp(".*");
+		return factory.apply(config);
+	}
+}

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/handler/predicate/CloudFoundryRouteServicePredicateFactoryTest.java

@@ -0,0 +1,61 @@
+package org.springframework.cloud.gateway.handler.predicate;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.function.Predicate;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.web.server.MockServerWebExchange;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * @author Andrew Fitzgerald
+ */
+public class CloudFoundryRouteServicePredicateFactoryTest {
+
+	private Predicate<ServerWebExchange> predicate;
+
+	@Before
+	public void setUp() throws Exception {
+		CloudFoundryRouteServicePredicateFactory factory = new CloudFoundryRouteServicePredicateFactory();
+		predicate = factory.apply(factory.newConfig());
+	}
+
+	@Test
+	public void itReturnsTrueWithAllHeadersPresent() {
+		MockServerHttpRequest request = MockServerHttpRequest.get("someurl")
+				.header(CloudFoundryRouteServicePredicateFactory.X_CF_FORWARDED_URL,
+						"url")
+				.header(CloudFoundryRouteServicePredicateFactory.X_CF_PROXY_METADATA,
+						"metadata")
+				.header(CloudFoundryRouteServicePredicateFactory.X_CF_PROXY_SIGNATURE,
+						"signature")
+				.build();
+		MockServerWebExchange exchange = MockServerWebExchange.from(request);
+
+		assertThat(predicate.test(exchange)).isTrue();
+	}
+
+	@Test
+	public void itReturnsFalseWithAHeadersMissing() {
+		MockServerHttpRequest request = MockServerHttpRequest.get("someurl")
+				.header(CloudFoundryRouteServicePredicateFactory.X_CF_FORWARDED_URL,
+						"url")
+				.header(CloudFoundryRouteServicePredicateFactory.X_CF_PROXY_METADATA,
+						"metadata")
+				.build();
+		MockServerWebExchange exchange = MockServerWebExchange.from(request);
+
+		assertThat(predicate.test(exchange)).isFalse();
+	}
+
+	@Test
+	public void itReturnsFalseWithNoHeaders() {
+		MockServerHttpRequest request = MockServerHttpRequest.get("someurl").build();
+		MockServerWebExchange exchange = MockServerWebExchange.from(request);
+
+		assertThat(predicate.test(exchange)).isFalse();
+	}
+}