Retrofit template: return body string directly when failed to parse response body as JSON

modules/swagger-codegen/src/main/resources/retrofit/service.mustache

@@ -2,8 +2,20 @@ package {{invokerPackage}};
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
+import com.google.gson.JsonParseException;
+
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.io.IOException;
+import java.lang.reflect.Type;
+
 import retrofit.RestAdapter;
+import retrofit.converter.ConversionException;
+import retrofit.converter.Converter;
 import retrofit.converter.GsonConverter;
+import retrofit.mime.TypedByteArray;
+import retrofit.mime.TypedInput;
+import retrofit.mime.TypedOutput;
 
 public class ServiceGenerator {
   // No need to instantiate this class.
@@ -15,9 +27,63 @@ public class ServiceGenerator {
         .create();
     RestAdapter adapter = new RestAdapter.Builder()
         .setEndpoint("{{basePath}}")
-        .setConverter(new GsonConverter(gson))
+        .setConverter(new GsonConverterWrapper(gson))
         .build();
 
     return adapter.create(serviceClass);
   }
 }
+
+/**
+ * This wrapper is to take care of this case:
+ * when the deserialization fails due to JsonParseException and the
+ * expected type is String, then just return the body string.
+ */
+class GsonConverterWrapper implements Converter {
+    private GsonConverter converter;
+
+    public GsonConverterWrapper(Gson gson) {
+        converter = new GsonConverter(gson);
+    }
+
+    @Override public Object fromBody(TypedInput body, Type type) throws ConversionException {
+        byte[] bodyBytes = readInBytes(body);
+        TypedByteArray newBody = new TypedByteArray(body.mimeType(), bodyBytes);
+        try {
+            return converter.fromBody(newBody, type);
+        } catch (ConversionException e) {
+            if (e.getCause() instanceof JsonParseException && type.equals(String.class)) {
+                return new String(bodyBytes);
+            } else {
+                throw e;
+            }
+        }
+    }
+
+    @Override public TypedOutput toBody(Object object) {
+        return converter.toBody(object);
+    }
+
+    private byte[] readInBytes(TypedInput body) throws ConversionException {
+        InputStream in = null;
+        try {
+            in = body.in();
+            ByteArrayOutputStream os = new ByteArrayOutputStream();
+            byte[] buffer = new byte[0xFFFF];
+            for (int len; (len = in.read(buffer)) != -1;)
+                os.write(buffer, 0, len);
+            os.flush();
+            return os.toByteArray();
+        } catch (IOException e) {
+            throw new ConversionException(e);
+        } finally {
+            if (in != null) {
+                try {
+                    in.close();
+                } catch (IOException ignored) {
+                }
+            }
+        }
+
+    }
+}

samples/client/petstore/retrofit/src/main/java/io/swagger/client/ServiceGenerator.java

@@ -2,8 +2,20 @@
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
+import com.google.gson.JsonParseException;
+
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.io.IOException;
+import java.lang.reflect.Type;
+
 import retrofit.RestAdapter;
+import retrofit.converter.ConversionException;
+import retrofit.converter.Converter;
 import retrofit.converter.GsonConverter;
+import retrofit.mime.TypedByteArray;
+import retrofit.mime.TypedInput;
+import retrofit.mime.TypedOutput;
 
 public class ServiceGenerator {
   // No need to instantiate this class.
@@ -15,9 +27,63 @@ public static <S> S createService(Class<S> serviceClass) {
         .create();
     RestAdapter adapter = new RestAdapter.Builder()
         .setEndpoint("http://petstore.swagger.io/v2")
-        .setConverter(new GsonConverter(gson))
+        .setConverter(new GsonConverterWrapper(gson))
         .build();
 
     return adapter.create(serviceClass);
   }
 }
+
+/**
+ * This wrapper is to take care of this case:
+ * when the deserialization fails due to JsonParseException and the
+ * expected type is String, then just return the body string.
+ */
+class GsonConverterWrapper implements Converter {
+    private GsonConverter converter;
+
+    public GsonConverterWrapper(Gson gson) {
+        converter = new GsonConverter(gson);
+    }
+
+    @Override public Object fromBody(TypedInput body, Type type) throws ConversionException {
+        byte[] bodyBytes = readInBytes(body);
+        TypedByteArray newBody = new TypedByteArray(body.mimeType(), bodyBytes);
+        try {
+            return converter.fromBody(newBody, type);
+        } catch (ConversionException e) {
+            if (e.getCause() instanceof JsonParseException && type.equals(String.class)) {
+                return new String(bodyBytes);
+            } else {
+                throw e;
+            }
+        }
+    }
+
+    @Override public TypedOutput toBody(Object object) {
+        return converter.toBody(object);
+    }
+
+    private byte[] readInBytes(TypedInput body) throws ConversionException {
+        InputStream in = null;
+        try {
+            in = body.in();
+            ByteArrayOutputStream os = new ByteArrayOutputStream();
+            byte[] buffer = new byte[0xFFFF];
+            for (int len; (len = in.read(buffer)) != -1;)
+                os.write(buffer, 0, len);
+            os.flush();
+            return os.toByteArray();
+        } catch (IOException e) {
+            throw new ConversionException(e);
+        } finally {
+            if (in != null) {
+                try {
+                    in.close();
+                } catch (IOException ignored) {
+                }
+            }
+        }
+
+    }
+}

samples/client/petstore/retrofit/src/main/java/io/swagger/client/api/PetApi.java

@@ -89,14 +89,14 @@ Void updatePetWithForm(
   /**
    * Deletes a pet
    * 
-   * @param apiKey 
    * @param petId Pet id to delete
+   * @param apiKey 
    * @return Void
    */
 
   @DELETE("/pet/{petId}")  
   Void deletePet(
-    @Header("api_key") String apiKey,@Path("petId") Long petId
+    @Path("petId") Long petId,@Header("api_key") String apiKey
   );  
 
   /**

samples/client/petstore/retrofit/src/main/java/io/swagger/client/model/Pet.java

@@ -34,13 +34,13 @@ public class Pet  {
      **/
     @ApiModelProperty(required = true, value = "")  
     @SerializedName("photoUrls")
-    private List<String> photoUrls = new ArrayList<String>() ;
+    private List<String> photoUrls = null;
 
     /**
      **/
     @ApiModelProperty(value = "")  
     @SerializedName("tags")
-    private List<Tag> tags = new ArrayList<Tag>() ;
+    private List<Tag> tags = null;
     public enum StatusEnum {
          available,  pending,  sold, 
     };

samples/client/petstore/retrofit/src/test/java/io/swagger/petstore/test/PetApiTest.java

@@ -120,7 +120,7 @@ public void testDeletePet() throws Exception {
         api.addPet(pet);
 
         Pet fetched = api.getPetById(pet.getId());
-        api.deletePet(null, fetched.getId());
+        api.deletePet(fetched.getId(), null);
 
         try {
             fetched = api.getPetById(fetched.getId());