moving json related stuff out of the core

Author: dotarj

src/PartialResponse.AspNetCore.Mvc.Formatters.Json/Internal/JsonSerializerExtensions.cs

@@ -0,0 +1,142 @@
+// Copyright (c) Arjen Post. See License.txt and Notice.txt in the project root for license information.
+
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace PartialResponse.AspNetCore.Mvc.Formatters.Json.Internal
+{
+    internal static class JsonSerializerExtensions
+    {
+        public static void Serialize(this JsonSerializer jsonSerializer, JsonWriter jsonWriter, object value, Func<string, bool> shouldSerialize)
+        {
+            if (value == null)
+            {
+                jsonSerializer.Serialize(jsonWriter, value);
+            }
+            else
+            {
+                var token = JToken.FromObject(value, jsonSerializer);
+
+                var array = token as JArray;
+
+                if (array != null)
+                {
+                    RemoveArrayElements(array, null, shouldSerialize, new Dictionary<string, bool>());
+
+                    array.WriteTo(jsonWriter);
+                }
+                else
+                {
+                    var @object = token as JObject;
+
+                    if (@object != null)
+                    {
+                        RemoveObjectProperties(@object, null, shouldSerialize, new Dictionary<string, bool>());
+
+                        @object.WriteTo(jsonWriter);
+                    }
+                    else
+                    {
+                        token.WriteTo(jsonWriter);
+                    }
+                }
+            }
+        }
+
+        private static void RemoveArrayElements(JArray array, string currentPath, Func<string, bool> shouldSerialize, Dictionary<string, bool> cache)
+        {
+            array.OfType<JObject>()
+                .ToList()
+                .ForEach(childObject => RemoveObjectProperties(childObject, currentPath, shouldSerialize, cache));
+
+            RemoveArrayIfEmpty(array);
+        }
+
+        private static void RemoveArrayIfEmpty(JArray array)
+        {
+            if (array.Count == 0)
+            {
+                if (array.Parent is JProperty && array.Parent.Parent != null)
+                {
+                    array.Parent.Remove();
+                }
+                else if (array.Parent is JArray)
+                {
+                    array.Remove();
+                }
+            }
+        }
+
+        private static void RemoveObjectProperties(JObject @object, string currentPath, Func<string, bool> shouldSerialize, Dictionary<string, bool> cache)
+        {
+            @object.Properties()
+                .Where(property =>
+                {
+                    var path = CombinePath(currentPath, property.Name);
+
+                    if (cache.ContainsKey(path))
+                    {
+                        return cache[path];
+                    }
+
+                    var result = !shouldSerialize(path);
+
+                    cache.Add(path, result);
+
+                    return result;
+                })
+                .ToList()
+                .ForEach(property => property.Remove());
+
+            @object.Properties()
+                .Where(property => property.Value is JObject)
+                .ToList()
+                .ForEach(property =>
+                {
+                    var path = CombinePath(currentPath, property.Name);
+
+                    RemoveObjectProperties((JObject)property.Value, path, shouldSerialize, cache);
+                });
+
+            @object.Properties()
+                .Where(property => property.Value is JArray)
+                .ToList()
+                .ForEach(property =>
+                {
+                    var path = CombinePath(currentPath, property.Name);
+
+                    RemoveArrayElements((JArray)property.Value, path, shouldSerialize, cache);
+                });
+
+            RemoveObjectIfEmpty(@object);
+        }
+
+        private static void RemoveObjectIfEmpty(JObject @object)
+        {
+            if (!@object.Properties().Any())
+            {
+                if (@object.Parent is JProperty && @object.Parent.Parent != null)
+                {
+                    @object.Parent.Remove();
+                }
+                else if (@object.Parent is JArray)
+                {
+                    @object.Remove();
+                }
+            }
+        }
+
+        private static string CombinePath(string path, string name)
+        {
+            if (string.IsNullOrEmpty(path))
+            {
+                return name;
+            }
+
+            return string.Format("{0}/{1}", path, name);
+        }
+    }
+}