Adds support for optional request body Fixes gh-126

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/annotation/RequestBodyParameterProcessor.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2013-2019 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.cloud.openfeign.annotation;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+
+import feign.MethodMetadata;
+import feign.Request;
+
+import org.springframework.cloud.openfeign.AnnotatedParameterProcessor;
+import org.springframework.web.bind.annotation.RequestBody;
+
+import static feign.Util.checkState;
+import static org.springframework.cloud.openfeign.support.SpringEncoder.OPTIONAL_REQUEST_BODY;
+
+/**
+ * {@Link RequestBody} annotation processor.
+ *
+ * @author Matt King
+ * @see AnnotatedParameterProcessor
+ */
+public class RequestBodyParameterProcessor implements AnnotatedParameterProcessor {
+
+	private static final Class<RequestBody> ANNOTATION = RequestBody.class;
+
+	@Override
+	public Class<? extends Annotation> getAnnotationType() {
+		return ANNOTATION;
+	}
+
+	@Override
+	public boolean processArgument(AnnotatedParameterContext context,
+			Annotation annotation, Method method) {
+		int parameterIndex = context.getParameterIndex();
+		MethodMetadata data = context.getMethodMetadata();
+		boolean required = ANNOTATION.cast(annotation).required();
+
+		checkState(data.bodyIndex() == null, "Only one request body is allowed.");
+
+		data.bodyIndex(parameterIndex);
+
+		if (!required) {
+			data.template().body(Request.Body.bodyTemplate(OPTIONAL_REQUEST_BODY, null));
+		}
+
+		return true;
+	}
+
+}

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SpringEncoder.java

@@ -58,6 +58,9 @@
  */
 public class SpringEncoder implements Encoder {
 
+	/** Constant to identify request body as optional. */
+	public static final String OPTIONAL_REQUEST_BODY = "OPTIONAL_REQUEST_BODY";
+
 	private static final Log log = LogFactory.getLog(SpringEncoder.class);
 
 	private final SpringFormEncoder springFormEncoder;
@@ -150,6 +153,11 @@ else if (messageConverter instanceof ProtobufHttpMessageConverter
 			}
 			throw new EncodeException(message);
 		}
+		else {
+			if (OPTIONAL_REQUEST_BODY.equals(request.bodyTemplate())) {
+				request.body(Request.Body.empty());
+			}
+		}
 	}
 
 	@SuppressWarnings("unchecked")

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SpringMvcContract.java

@@ -40,6 +40,7 @@
 import org.springframework.cloud.openfeign.annotation.MatrixVariableParameterProcessor;
 import org.springframework.cloud.openfeign.annotation.PathVariableParameterProcessor;
 import org.springframework.cloud.openfeign.annotation.QueryMapParameterProcessor;
+import org.springframework.cloud.openfeign.annotation.RequestBodyParameterProcessor;
 import org.springframework.cloud.openfeign.annotation.RequestHeaderParameterProcessor;
 import org.springframework.cloud.openfeign.annotation.RequestParamParameterProcessor;
 import org.springframework.cloud.openfeign.annotation.RequestPartParameterProcessor;
@@ -359,6 +360,7 @@ private List<AnnotatedParameterProcessor> getDefaultAnnotatedArgumentsProcessors
 
 		annotatedArgumentResolvers.add(new MatrixVariableParameterProcessor());
 		annotatedArgumentResolvers.add(new PathVariableParameterProcessor());
+		annotatedArgumentResolvers.add(new RequestBodyParameterProcessor());
 		annotatedArgumentResolvers.add(new RequestParamParameterProcessor());
 		annotatedArgumentResolvers.add(new RequestHeaderParameterProcessor());
 		annotatedArgumentResolvers.add(new QueryMapParameterProcessor());

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/support/SpringEncoderTests.java

@@ -18,11 +18,13 @@
 
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
+import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
+import feign.Request;
 import feign.RequestTemplate;
 import feign.codec.EncodeException;
 import feign.codec.Encoder;
@@ -54,6 +56,7 @@
 import org.springframework.web.multipart.MultipartFile;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.cloud.openfeign.support.SpringEncoder.OPTIONAL_REQUEST_BODY;
 import static org.springframework.http.HttpHeaders.ACCEPT;
 import static org.springframework.http.HttpHeaders.CONTENT_LENGTH;
 import static org.springframework.http.HttpHeaders.CONTENT_TYPE;
@@ -185,6 +188,20 @@ public void testMultipartFile2() {
 				.as("Body content cannot be decoded").contains("hi");
 	}
 
+	@Test
+	public void testOptionalBody() {
+		Encoder encoder = this.context.getInstance("foo", Encoder.class);
+		assertThat(encoder).isNotNull();
+
+		RequestTemplate request = new RequestTemplate();
+		request.body(Request.Body.bodyTemplate(OPTIONAL_REQUEST_BODY, (Charset) null));
+
+		encoder.encode(null, Object.class, request);
+
+		assertThat(request.requestBody())
+				.isEqualToComparingFieldByField(Request.Body.empty());
+	}
+
 	protected interface TestClient {
 
 	}

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/support/SpringMvcContractTests.java

@@ -64,6 +64,8 @@
 import static com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility.NONE;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assume.assumeTrue;
+import static org.springframework.cloud.openfeign.support.SpringEncoder.OPTIONAL_REQUEST_BODY;
+import static org.springframework.web.util.UriUtils.encode;
 
 /**
  * @author chadjaros
@@ -530,6 +532,26 @@ public void testProcessQueryMapMoreThanOnce() throws Exception {
 		this.contract.parseAndValidateMetadata(method.getDeclaringClass(), method);
 	}
 
+	@Test
+	public void testRequestBody_optional() throws Exception {
+		Method method = TestTemplate_RequestBody.class.getDeclaredMethod("requestBody",
+				TestObject.class);
+		MethodMetadata data = contract
+				.parseAndValidateMetadata(method.getDeclaringClass(), method);
+
+		assertThat(data.template().bodyTemplate()).isEqualTo(OPTIONAL_REQUEST_BODY);
+	}
+
+	@Test
+	public void testRequestBody_required() throws Exception {
+		Method method = TestTemplate_RequestBody.class
+				.getDeclaredMethod("requestBodyRequired", TestObject.class);
+		MethodMetadata data = contract
+				.parseAndValidateMetadata(method.getDeclaringClass(), method);
+
+		assertThat(data.template().bodyTemplate()).isNotEqualTo(OPTIONAL_REQUEST_BODY);
+	}
+
 	@Test
 	public void testMatrixVariable_MapParam() throws Exception {
 		Method method = TestTemplate_MatrixVariable.class
@@ -770,6 +792,16 @@ public interface TestTemplate_MatrixVariable {
 
 	}
 
+	public interface TestTemplate_RequestBody {
+
+		@RequestMapping(path = "/requestBody")
+		String requestBody(@RequestBody(required = false) TestObject body);
+
+		@RequestMapping(path = "/requestBody_required")
+		String requestBodyRequired(@RequestBody TestObject body);
+
+	}
+
 	@JsonAutoDetect
 	@RequestMapping("/advanced")
 	public interface TestTemplate_Advanced {