Use charset from response Content-Type header to decode

jackson/src/main/java/feign/jackson/JacksonDecoder.java

@@ -13,15 +13,17 @@
  */
 package feign.jackson;
 
-import com.fasterxml.jackson.databind.DeserializationFeature;
-import com.fasterxml.jackson.databind.Module;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.RuntimeJsonMappingException;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.Reader;
 import java.lang.reflect.Type;
+import java.nio.charset.Charset;
+import java.util.Collection;
 import java.util.Collections;
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.Module;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.RuntimeJsonMappingException;
 import feign.Response;
 import feign.Util;
 import feign.codec.Decoder;
@@ -47,7 +49,8 @@ public JacksonDecoder(ObjectMapper mapper) {
   public Object decode(Response response, Type type) throws IOException {
     if (response.body() == null)
       return null;
-    Reader reader = response.body().asReader(Util.UTF_8);
+    Charset charset = getResponseCharset(response);
+    Reader reader = response.body().asReader(charset);
     if (!reader.markSupported()) {
       reader = new BufferedReader(reader, 1);
     }
@@ -66,4 +69,23 @@ public Object decode(Response response, Type type) throws IOException {
       throw e;
     }
   }
+
+  private Charset getResponseCharset(Response response) {
+
+    Collection<String> contentTypeHeaders = response.headers().get("Content-Type");
+
+    if (contentTypeHeaders != null) {
+      for (String contentTypeHeader : contentTypeHeaders) {
+        String[] contentTypeParmeters = contentTypeHeader.split(";");
+        if (contentTypeParmeters.length > 1) {
+          String[] charsetParts = contentTypeParmeters[1].split("=");
+          if (charsetParts.length == 2 && "charset".equalsIgnoreCase(charsetParts[0].trim())) {
+            return Charset.forName(charsetParts[1]);
+          }
+        }
+      }
+    }
+
+    return Util.UTF_8;
+  }
 }

jackson/src/test/java/feign/jackson/JacksonCodecTest.java

@@ -28,9 +28,12 @@
 import org.junit.Test;
 import java.io.Closeable;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.LinkedList;
@@ -169,6 +172,29 @@ public void customEncoder() {
         + "} ]");
   }
 
+  @Test
+  public void decoderCharset() throws IOException {
+    Zone zone = new Zone("denominator.io.", "ÁÉÍÓÚÀÈÌÒÙÄËÏÖÜÑ");
+
+    Map<String, Collection<String>> headers = new HashMap<String, Collection<String>>();
+    headers.put("Content-Type", Arrays.asList("application/json;charset=ISO-8859-1"));
+
+    Response response = Response.builder()
+        .status(200)
+        .reason("OK")
+        .request(Request.create(HttpMethod.GET, "/api", Collections.emptyMap(), null, Util.UTF_8))
+        .headers(headers)
+        .body(new String("" //
+            + "{" + System.lineSeparator()
+            + "  \"name\" : \"DENOMINATOR.IO.\"," + System.lineSeparator()
+            + "  \"id\" : \"ÁÉÍÓÚÀÈÌÒÙÄËÏÖÜÑ\"" + System.lineSeparator()
+            + "}").getBytes(StandardCharsets.ISO_8859_1))
+        .build();
+    assertEquals(zone.get("id"),
+        ((Zone) new JacksonDecoder().decode(response, new TypeReference<Zone>() {}.getType()))
+            .get("id"));
+  }
+
   @Test
   public void decodesIterator() throws Exception {
     List<Zone> zones = new LinkedList<Zone>();