add encoder, decoder and contract to feign properties, so we can override the default value with properties (#2687)

docs/src/main/asciidoc/spring-cloud-netflix.adoc

@@ -1131,6 +1131,9 @@ feign:
           - com.example.FooRequestInterceptor
           - com.example.BarRequestInterceptor
         decode404: false
+        encoder: com.example.SimpleEncoder
+        decoder: com.example.SimpleDecoder
+        contract: com.example.SimpleContract
 ----
 
 Default configurations can be specified in the `@EnableFeignClients` attribute `defaultConfiguration` in a similar manner as described above. The difference is that this configuration will apply to _all_ feign clients.

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/FeignClientFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -179,6 +179,18 @@ class FeignClientFactoryBean implements FactoryBean<Object>, InitializingBean,
 				builder.decode404();
 			}
 		}
+
+		if (Objects.nonNull(config.getEncoder())) {
+			builder.encoder(getOrInstantiate(config.getEncoder()));
+		}
+
+		if (Objects.nonNull(config.getDecoder())) {
+			builder.decoder(getOrInstantiate(config.getDecoder()));
+		}
+
+		if (Objects.nonNull(config.getContract())) {
+			builder.contract(getOrInstantiate(config.getContract()));
+		}
 	}
 
 	private <T> T getOrInstantiate(Class<T> tClass) {

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/FeignClientProperties.java

@@ -15,9 +15,12 @@
  */
 package org.springframework.cloud.netflix.feign;
 
+import feign.Contract;
 import feign.Logger;
 import feign.RequestInterceptor;
 import feign.Retryer;
+import feign.codec.Decoder;
+import feign.codec.Encoder;
 import feign.codec.ErrorDecoder;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 
@@ -93,6 +96,12 @@ public class FeignClientProperties {
 
 		private Boolean decode404;
 
+		private Class<Decoder> decoder;
+
+		private Class<Encoder> encoder;
+
+		private Class<Contract> contract;
+
 		public Logger.Level getLoggerLevel() {
 			return loggerLevel;
 		}
@@ -149,6 +158,30 @@ public class FeignClientProperties {
 			this.decode404 = decode404;
 		}
 
+		public Class<Decoder> getDecoder() {
+			return decoder;
+		}
+
+		public void setDecoder(Class<Decoder> decoder) {
+			this.decoder = decoder;
+		}
+
+		public Class<Encoder> getEncoder() {
+			return encoder;
+		}
+
+		public void setEncoder(Class<Encoder> encoder) {
+			this.encoder = encoder;
+		}
+
+		public Class<Contract> getContract() {
+			return contract;
+		}
+
+		public void setContract(Class<Contract> contract) {
+			this.contract = contract;
+		}
+
 		@Override
 		public boolean equals(Object o) {
 			if (this == o) return true;
@@ -160,13 +193,16 @@ public class FeignClientProperties {
 					Objects.equals(retryer, that.retryer) &&
 					Objects.equals(errorDecoder, that.errorDecoder) &&
 					Objects.equals(requestInterceptors, that.requestInterceptors) &&
-					Objects.equals(decode404, that.decode404);
+					Objects.equals(decode404, that.decode404) &&
+					Objects.equals(encoder, that.encoder) &&
+					Objects.equals(decoder, that.decoder) &&
+					Objects.equals(contract, that.contract);
 		}
 
 		@Override
 		public int hashCode() {
 			return Objects.hash(loggerLevel, connectTimeout, readTimeout, retryer,
-					errorDecoder, requestInterceptors, decode404);
+					errorDecoder, requestInterceptors, decode404, encoder, decoder, contract);
 		}
 	}
 

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/feign/FeignClientUsingPropertiesTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -20,6 +20,8 @@ import feign.RequestInterceptor;
 import feign.RequestTemplate;
 import feign.RetryableException;
 import feign.Retryer;
+import feign.codec.EncodeException;
+import feign.codec.Encoder;
 import feign.codec.ErrorDecoder;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -30,6 +32,8 @@ import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.TestPropertySource;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@@ -38,8 +42,11 @@ import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
 
 import javax.servlet.http.HttpServletRequest;
+import java.lang.reflect.Type;
+import java.util.Collections;
+import java.util.Map;
 
-import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
 /**
@@ -64,6 +71,8 @@ public class FeignClientUsingPropertiesTests {
 
 	private FeignClientFactoryBean barFactoryBean;
 
+	private FeignClientFactoryBean formFactoryBean;
+
 	public FeignClientUsingPropertiesTests() {
 		fooFactoryBean = new FeignClientFactoryBean();
 		fooFactoryBean.setName("foo");
@@ -72,6 +81,10 @@ public class FeignClientUsingPropertiesTests {
 		barFactoryBean = new FeignClientFactoryBean();
 		barFactoryBean.setName("bar");
 		barFactoryBean.setType(FeignClientFactoryBean.class);
+
+		formFactoryBean = new FeignClientFactoryBean();
+		formFactoryBean.setName("form");
+		formFactoryBean.setType(FeignClientFactoryBean.class);
 	}
 
 	public FooClient fooClient() {
@@ -84,10 +97,15 @@ public class FeignClientUsingPropertiesTests {
 		return barFactoryBean.feign(context).target(BarClient.class, "http://localhost:" + this.port);
 	}
 
+	public FormClient formClient() {
+		formFactoryBean.setApplicationContext(applicationContext);
+		return formFactoryBean.feign(context).target(FormClient.class, "http://localhost:" + this.port);
+	}
+
 	@Test
 	public void testFoo() {
 		String response = fooClient().foo();
-		assertNotNull("OK", response);
+		assertEquals("OK", response);
 	}
 
 	@Test(expected = RetryableException.class)
@@ -96,6 +114,13 @@ public class FeignClientUsingPropertiesTests {
 		fail("it should timeout");
 	}
 
+	@Test
+	public void testForm() {
+		Map<String, String> request = Collections.singletonMap("form", "Data");
+		String response = formClient().form(request);
+		assertEquals("Data", response);
+	}
+
 	protected interface FooClient {
 
 		@RequestMapping(method = RequestMethod.GET, value = "/foo")
@@ -108,6 +133,14 @@ public class FeignClientUsingPropertiesTests {
 		String bar();
 	}
 
+	protected interface FormClient {
+
+		@RequestMapping(value = "/form", method = RequestMethod.POST,
+				consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
+		String form(Map<String, String> form);
+
+	}
+
 	@Configuration
 	@EnableAutoConfiguration
 	@RestController
@@ -129,6 +162,12 @@ public class FeignClientUsingPropertiesTests {
 			return "OK";
 		}
 
+		@RequestMapping(value = "/form", method = RequestMethod.POST,
+				consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
+		public String form(HttpServletRequest request) {
+			return request.getParameter("form");
+		}
+
 	}
 
 	public static class FooRequestInterceptor implements RequestInterceptor {
@@ -161,4 +200,19 @@ public class FeignClientUsingPropertiesTests {
 	public static class DefaultErrorDecoder extends ErrorDecoder.Default {
 	}
 
+	public static class FormEncoder implements Encoder {
+
+		@Override
+		public void encode(Object o, Type type, RequestTemplate requestTemplate) throws EncodeException {
+			Map<String, String> form = (Map<String, String>) o;
+			StringBuilder builder = new StringBuilder();
+			form.forEach((key, value) -> {
+				builder.append(key + "=" + value + "&");
+			});
+
+			requestTemplate.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE);
+			requestTemplate.body(builder.toString());
+		}
+	}
+
 }

spring-cloud-netflix-core/src/test/resources/feign-properties.properties

@@ -16,4 +16,6 @@ feign.client.config.foo.requestInterceptors[0]=org.springframework.cloud.netflix
 feign.client.config.foo.requestInterceptors[1]=org.springframework.cloud.netflix.feign.FeignClientUsingPropertiesTests.BarRequestInterceptor
 
 feign.client.config.bar.connectTimeout=1000
-feign.client.config.bar.readTimeout=1000
+feign.client.config.bar.readTimeout=1000
+
+feign.client.config.form.encoder=org.springframework.cloud.netflix.feign.FeignClientUsingPropertiesTests.FormEncoder