Allow @RequestPart user-defined POJOs

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2019 the original author or authors.
+ * Copyright 2013-2020 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.
@@ -40,6 +40,7 @@
 import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
 import org.springframework.cloud.openfeign.support.PageJacksonModule;
 import org.springframework.cloud.openfeign.support.PageableSpringEncoder;
+import org.springframework.cloud.openfeign.support.PojoFormWriter;
 import org.springframework.cloud.openfeign.support.ResponseEntityDecoder;
 import org.springframework.cloud.openfeign.support.SpringDecoder;
 import org.springframework.cloud.openfeign.support.SpringEncoder;
@@ -54,6 +55,7 @@
 /**
  * @author Dave Syer
  * @author Venil Noronha
+ * @author Darren Foong
  */
 @Configuration(proxyBeanMethods = false)
 public class FeignClientsConfiguration {
@@ -73,6 +75,9 @@ public class FeignClientsConfiguration {
 	@Autowired(required = false)
 	private SpringDataWebProperties springDataWebProperties;
 
+	@Autowired(required = false)
+	private PojoFormWriter pojoFormWriter;
+
 	@Bean
 	@ConditionalOnMissingBean
 	public Decoder feignDecoder() {
@@ -84,15 +89,29 @@ public Decoder feignDecoder() {
 	@ConditionalOnMissingBean
 	@ConditionalOnMissingClass("org.springframework.data.domain.Pageable")
 	public Encoder feignEncoder() {
-		return new SpringEncoder(this.messageConverters);
+		if (this.pojoFormWriter != null) {
+			return new SpringEncoder(this.pojoFormWriter, this.messageConverters);
+		}
+		else {
+			return new SpringEncoder(this.messageConverters);
+		}
 	}
 
 	@Bean
 	@ConditionalOnClass(name = "org.springframework.data.domain.Pageable")
 	@ConditionalOnMissingBean
 	public Encoder feignEncoderPageable() {
-		PageableSpringEncoder encoder = new PageableSpringEncoder(
-				new SpringEncoder(this.messageConverters));
+		PageableSpringEncoder encoder;
+
+		if (this.pojoFormWriter != null) {
+			encoder = new PageableSpringEncoder(
+					new SpringEncoder(this.pojoFormWriter, this.messageConverters));
+		}
+		else {
+			encoder = new PageableSpringEncoder(
+					new SpringEncoder(this.messageConverters));
+		}
+
 		if (springDataWebProperties != null) {
 			encoder.setPageParameter(
 					springDataWebProperties.getPageable().getPageParameter());

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

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2013-2020 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.cloud.openfeign.support;
+
+import java.io.IOException;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.MediaType;
+import org.springframework.stereotype.Component;
+
+/**
+ * @author Darren Foong
+ */
+@Component
+public class JsonPojoFormWriter extends PojoFormWriter {
+
+	@Autowired
+	private ObjectMapper objectMapper;
+
+	@Override
+	protected MediaType getContentType() {
+		return MediaType.APPLICATION_JSON;
+	}
+
+	@Override
+	protected String writePojoAsString(Object object) throws IOException {
+		return objectMapper.writeValueAsString(object);
+	}
+
+}

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

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2013-2020 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.cloud.openfeign.support;
+
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.function.Predicate;
+
+import feign.codec.EncodeException;
+import feign.form.multipart.AbstractWriter;
+import feign.form.multipart.Output;
+import feign.form.util.PojoUtil;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.multipart.MultipartFile;
+
+import static feign.form.ContentProcessor.CRLF;
+import static feign.form.util.PojoUtil.isUserPojo;
+
+/**
+ * @author Darren Foong
+ */
+public abstract class PojoFormWriter extends AbstractWriter {
+
+	@Override
+	public boolean isApplicable(Object object) {
+		return !isTypeOrCollection(object, o -> o instanceof MultipartFile)
+				&& isTypeOrCollection(object, PojoUtil::isUserPojo);
+	}
+
+	@Override
+	public void write(Output output, String key, Object object) throws EncodeException {
+		try {
+			String string = new StringBuilder()
+					.append("Content-Disposition: form-data; name=\"").append(key)
+					.append('"').append(CRLF).append("Content-Type: ")
+					.append(getContentType()).append("; charset=")
+					.append(output.getCharset().name()).append(CRLF).append(CRLF)
+					.append(writePojoAsString(object)).toString();
+
+			output.write(string);
+		}
+		catch (IOException e) {
+			throw new EncodeException(e.getMessage());
+		}
+	}
+
+	protected abstract MediaType getContentType();
+
+	protected abstract String writePojoAsString(Object object) throws IOException;
+
+	private boolean isTypeOrCollection(Object object, Predicate<Object> isType) {
+		if (object.getClass().isArray()) {
+			Object[] array = (Object[]) object;
+
+			return array.length > 1 && isType.test(array[0]);
+		}
+		else if (object instanceof Iterable) {
+			Iterable<?> iterable = (Iterable<?>) object;
+			Iterator<?> iterator = iterable.iterator();
+
+			return iterator.hasNext() && isType.test(iterator.next());
+		}
+		else {
+			return isType.test(object);
+		}
+	}
+
+}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2019 the original author or authors.
+ * Copyright 2013-2020 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.
@@ -54,16 +54,24 @@
  * @author Scien Jus
  * @author Ahmad Mozafarnia
  * @author Aaron Whiteside
+ * @author Darren Foong
  */
 public class SpringEncoder implements Encoder {
 
 	private static final Log log = LogFactory.getLog(SpringEncoder.class);
 
-	private final SpringFormEncoder springFormEncoder = new SpringFormEncoder();
+	private SpringFormEncoder springFormEncoder;
 
 	private final ObjectFactory<HttpMessageConverters> messageConverters;
 
 	public SpringEncoder(ObjectFactory<HttpMessageConverters> messageConverters) {
+		this.springFormEncoder = new SpringFormEncoder();
+		this.messageConverters = messageConverters;
+	}
+
+	public SpringEncoder(PojoFormWriter writer,
+			ObjectFactory<HttpMessageConverters> messageConverters) {
+		this.springFormEncoder = new SpringPojoFormEncoder(writer);
 		this.messageConverters = messageConverters;
 	}
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2019 the original author or authors.
+ * Copyright 2013-2020 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.
@@ -28,6 +28,7 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 import feign.Contract;
 import feign.Feign;
@@ -42,6 +43,7 @@
 import org.springframework.cloud.openfeign.annotation.RequestHeaderParameterProcessor;
 import org.springframework.cloud.openfeign.annotation.RequestParamParameterProcessor;
 import org.springframework.cloud.openfeign.annotation.RequestPartParameterProcessor;
+import org.springframework.cloud.openfeign.encoding.HttpEncoding;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.ResourceLoaderAware;
 import org.springframework.core.DefaultParameterNameDiscoverer;
@@ -54,6 +56,7 @@
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.http.MediaType;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -72,6 +75,7 @@
  * @author Olga Maciaszek-Sharma
  * @author Aaron Whiteside
  * @author Artyom Romanenko
+ * @author Darren Foong
  */
 public class SpringMvcContract extends Contract.BaseContract
 		implements ResourceLoaderAware {
@@ -272,6 +276,17 @@ private void checkOne(Method method, Object[] values, String fieldName) {
 	@Override
 	protected boolean processAnnotationsOnParameter(MethodMetadata data,
 			Annotation[] annotations, int paramIndex) {
+		boolean isMultipartFormData = false;
+
+		Collection<String> contentTypes = data.template().headers()
+				.get(HttpEncoding.CONTENT_TYPE);
+
+		if (contentTypes != null && !contentTypes.isEmpty()) {
+			String type = contentTypes.iterator().next();
+			isMultipartFormData = Objects.equals(MediaType.valueOf(type),
+					MediaType.MULTIPART_FORM_DATA);
+		}
+
 		boolean isHttpAnnotation = false;
 
 		AnnotatedParameterProcessor.AnnotatedParameterContext context = new SimpleAnnotatedParameterContext(
@@ -291,7 +306,8 @@ protected boolean processAnnotationsOnParameter(MethodMetadata data,
 			}
 		}
 
-		if (isHttpAnnotation && data.indexToExpander().get(paramIndex) == null) {
+		if (!isMultipartFormData && isHttpAnnotation
+				&& data.indexToExpander().get(paramIndex) == null) {
 			TypeDescriptor typeDescriptor = createTypeDescriptor(method, paramIndex);
 			if (this.conversionService.canConvert(typeDescriptor,
 					STRING_TYPE_DESCRIPTOR)) {

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

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2013-2020 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.cloud.openfeign.support;
+
+import feign.form.MultipartFormContentProcessor;
+import feign.form.spring.SpringFormEncoder;
+
+import static feign.form.ContentType.MULTIPART;
+
+/**
+ * @author Darren Foong
+ */
+public class SpringPojoFormEncoder extends SpringFormEncoder {
+
+	public SpringPojoFormEncoder(PojoFormWriter pojoFormWriter) {
+		super();
+
+		MultipartFormContentProcessor processor = (MultipartFormContentProcessor) getContentProcessor(
+				MULTIPART);
+		processor.addFirstWriter(pojoFormWriter);
+	}
+
+}