Merge fix gh 225 (#272)

* Fix bug in SpringEncoder (#225)

This commit fixes a bug in the SpringEncoder that causes the bodyType to
be ignored and not passed to generic message converters.

Fixes gh-225

* Refactor changes based on Olga Maciaszek's review

* Add Ahmad Mozafarnia to authors.

Co-authored-by: Ahmad Mozafarnia <ahmad.mozafarnia@gmail.com>

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

@@ -40,6 +40,7 @@ import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpOutputMessage;
 import org.springframework.http.MediaType;
 import org.springframework.http.converter.ByteArrayHttpMessageConverter;
+import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter;
 import org.springframework.web.multipart.MultipartFile;
@@ -50,6 +51,7 @@ import static org.springframework.cloud.openfeign.support.FeignUtils.getHttpHead
 /**
  * @author Spencer Gibb
  * @author Scien Jus
+ * @author Ahmad Mozafarnia
  */
 public class SpringEncoder implements Encoder {
 
@@ -68,7 +70,6 @@ public class SpringEncoder implements Encoder {
 			throws EncodeException {
 		// template.body(conversionService.convert(object, String.class));
 		if (requestBody != null) {
-			Class<?> requestType = requestBody.getClass();
 			Collection<String> contentTypes = request.headers()
 					.get(HttpEncoding.CONTENT_TYPE);
 
@@ -91,31 +92,24 @@ public class SpringEncoder implements Encoder {
 				}
 			}
 
-			for (HttpMessageConverter<?> messageConverter : this.messageConverters
+			for (HttpMessageConverter messageConverter : this.messageConverters
 					.getObject().getConverters()) {
-				if (messageConverter.canWrite(requestType, requestContentType)) {
-					if (log.isDebugEnabled()) {
-						if (requestContentType != null) {
-							log.debug("Writing [" + requestBody + "] as \""
-									+ requestContentType + "\" using [" + messageConverter
-									+ "]");
-						}
-						else {
-							log.debug("Writing [" + requestBody + "] using ["
-									+ messageConverter + "]");
-						}
-
-					}
-
-					FeignOutputMessage outputMessage = new FeignOutputMessage(request);
-					try {
-						@SuppressWarnings("unchecked")
-						HttpMessageConverter<Object> copy = (HttpMessageConverter<Object>) messageConverter;
-						copy.write(requestBody, requestContentType, outputMessage);
+				FeignOutputMessage outputMessage;
+				try {
+					if (messageConverter instanceof GenericHttpMessageConverter) {
+						outputMessage = checkAndWrite(requestBody, bodyType,
+								requestContentType,
+								(GenericHttpMessageConverter) messageConverter, request);
 					}
-					catch (IOException ex) {
-						throw new EncodeException("Error converting request body", ex);
+					else {
+						outputMessage = checkAndWrite(requestBody, requestContentType,
+								messageConverter, request);
 					}
+				}
+				catch (IOException ex) {
+					throw new EncodeException("Error converting request body", ex);
+				}
+				if (outputMessage != null) {
 					// clear headers
 					request.headers(null);
 					// converters can modify headers, so update the request
@@ -141,7 +135,7 @@ public class SpringEncoder implements Encoder {
 				}
 			}
 			String message = "Could not write request: no suitable HttpMessageConverter "
-					+ "found for request type [" + requestType.getName() + "]";
+					+ "found for request type [" + requestBody.getClass().getName() + "]";
 			if (requestContentType != null) {
 				message += " and content type [" + requestContentType + "]";
 			}
@@ -149,6 +143,49 @@ public class SpringEncoder implements Encoder {
 		}
 	}
 
+	@SuppressWarnings("unchecked")
+	private FeignOutputMessage checkAndWrite(Object body, MediaType contentType,
+			HttpMessageConverter converter, RequestTemplate request) throws IOException {
+		if (converter.canWrite(body.getClass(), contentType)) {
+			logBeforeWrite(body, contentType, converter);
+			FeignOutputMessage outputMessage = new FeignOutputMessage(request);
+			converter.write(body, contentType, outputMessage);
+			return outputMessage;
+		}
+		else {
+			return null;
+		}
+	}
+
+	@SuppressWarnings("unchecked")
+	private FeignOutputMessage checkAndWrite(Object body, Type genericType,
+			MediaType contentType, GenericHttpMessageConverter converter,
+			RequestTemplate request) throws IOException {
+		if (converter.canWrite(genericType, body.getClass(), contentType)) {
+			logBeforeWrite(body, contentType, converter);
+			FeignOutputMessage outputMessage = new FeignOutputMessage(request);
+			converter.write(body, genericType, contentType, outputMessage);
+			return outputMessage;
+		}
+		else {
+			return null;
+		}
+	}
+
+	private void logBeforeWrite(Object requestBody, MediaType requestContentType,
+			HttpMessageConverter messageConverter) {
+		if (log.isDebugEnabled()) {
+			if (requestContentType != null) {
+				log.debug("Writing [" + requestBody + "] as \"" + requestContentType
+						+ "\" using [" + messageConverter + "]");
+			}
+			else {
+				log.debug(
+						"Writing [" + requestBody + "] using [" + messageConverter + "]");
+			}
+		}
+	}
+
 	private final class FeignOutputMessage implements HttpOutputMessage {
 
 		private final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

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

@@ -17,9 +17,11 @@
 package org.springframework.cloud.openfeign.support;
 
 import java.io.IOException;
+import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.nio.charset.Charset;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 
 import feign.RequestTemplate;
@@ -35,12 +37,15 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.cloud.openfeign.FeignContext;
+import org.springframework.cloud.openfeign.encoding.HttpEncoding;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.HttpInputMessage;
 import org.springframework.http.HttpOutputMessage;
 import org.springframework.http.MediaType;
 import org.springframework.http.converter.AbstractGenericHttpMessageConverter;
+import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.http.converter.HttpMessageNotWritableException;
@@ -60,6 +65,7 @@ import static org.springframework.http.MediaType.MULTIPART_FORM_DATA_VALUE;
 /**
  * @author Spencer Gibb
  * @author Olga Maciaszek-Sharma
+ * @author Ahmad Mozafarnia
  */
 @RunWith(SpringJUnit4ClassRunner.class)
 @SpringBootTest(classes = SpringEncoderTests.Application.class,
@@ -75,6 +81,10 @@ public class SpringEncoderTests {
 	@Qualifier("myHttpMessageConverter")
 	private HttpMessageConverter<?> myConverter;
 
+	@Autowired
+	@Qualifier("myGenericHttpMessageConverter")
+	private GenericHttpMessageConverter<?> myGenericConverter;
+
 	@Test
 	public void testCustomHttpMessageConverter() {
 		Encoder encoder = this.context.getInstance("foo", Encoder.class);
@@ -97,6 +107,34 @@ public class SpringEncoderTests {
 				.isEqualTo(Charset.forName("UTF-8"));
 	}
 
+	// gh-225
+	@Test
+	public void testCustomGenericHttpMessageConverter() {
+		Encoder encoder = this.context.getInstance("foo", Encoder.class);
+		assertThat(encoder).isNotNull();
+		RequestTemplate request = new RequestTemplate();
+
+		ParameterizedTypeReference<List<String>> stringListType = new ParameterizedTypeReference<List<String>>() {
+		};
+
+		request.header(HttpEncoding.CONTENT_TYPE, "application/mygenerictype");
+		encoder.encode(Collections.singletonList("hi"), stringListType.getType(),
+				request);
+
+		Collection<String> contentTypeHeader = request.headers().get("Content-Type");
+		assertThat(contentTypeHeader).as("missing content type header").isNotNull();
+		assertThat(contentTypeHeader.isEmpty()).as("missing content type header")
+				.isFalse();
+
+		String header = contentTypeHeader.iterator().next();
+		assertThat(header).as("content type header is wrong")
+				.isEqualTo("application/mygenerictype");
+
+		assertThat(request.requestCharset()).as("request charset is null").isNotNull();
+		assertThat(request.requestCharset()).as("request charset is wrong")
+				.isEqualTo(Charset.forName("UTF-8"));
+	}
+
 	@Test
 	public void testBinaryData() {
 		Encoder encoder = this.context.getInstance("foo", Encoder.class);
@@ -179,6 +217,11 @@ public class SpringEncoderTests {
 			return new MyHttpMessageConverter();
 		}
 
+		@Bean
+		GenericHttpMessageConverter<?> myGenericHttpMessageConverter() {
+			return new MyGenericHttpMessageConverter();
+		}
+
 		private static class MyHttpMessageConverter
 				extends AbstractGenericHttpMessageConverter<Object> {
 
@@ -223,6 +266,63 @@ public class SpringEncoderTests {
 
 		}
 
+		private static class MyGenericHttpMessageConverter
+				extends AbstractGenericHttpMessageConverter<Object> {
+
+			MyGenericHttpMessageConverter() {
+				super(new MediaType("application", "mygenerictype"));
+			}
+
+			private boolean isStringList(Type type) {
+				if (type instanceof ParameterizedType) {
+					ParameterizedType parameterizedType = (ParameterizedType) type;
+					return parameterizedType.getRawType() == List.class
+							&& parameterizedType
+									.getActualTypeArguments()[0] == String.class;
+				}
+				else {
+					return false;
+				}
+			}
+
+			@Override
+			protected boolean supports(Class<?> clazz) {
+				return clazz == List.class;
+			}
+
+			@Override
+			public boolean canWrite(Type type, Class<?> clazz, MediaType mediaType) {
+				return canWrite(mediaType) && isStringList(type);
+			}
+
+			@Override
+			public boolean canRead(Type type, Class<?> contextClass,
+					MediaType mediaType) {
+				return canRead(mediaType) && isStringList(type);
+			}
+
+			@Override
+			protected void writeInternal(Object o, Type type,
+					HttpOutputMessage outputMessage)
+					throws IOException, HttpMessageNotWritableException {
+
+			}
+
+			@Override
+			public Object read(Type type, Class<?> contextClass,
+					HttpInputMessage inputMessage)
+					throws IOException, HttpMessageNotReadableException {
+				return null;
+			}
+
+			@Override
+			protected Object readInternal(Class<?> clazz, HttpInputMessage inputMessage)
+					throws IOException, HttpMessageNotReadableException {
+				return null;
+			}
+
+		}
+
 	}
 
 	class MediaTypeMatcher implements ArgumentMatcher<MediaType> {