Feb 22 2018

Json.NET 11.0 Release 1 - .NET Standard 2.0, JsonConverters, JSON Path and more

.NET Standard 2.0

The big new feature in Json.NET 11 Release 1 is targeted support for .NET Standard 2.0.

There are two main benefits of a library like Json.NET targeting .NET Standard 2.0. The first is more APIs: Json.NET with .NET Standard 2.0 almost matches Json.NET on the traditional Windows .NET Framework in features.

For example, fans of serializing DataSets to and from JSON rejoice, .NET Core now supports your pro-DataSet lifestyle:

DataTable dt = new DataTable();
 dt.Columns.Add("PackageId", typeof(string));
 dt.Columns.Add("Version", typeof(string));
 dt.Columns.Add("ReleaseDate", typeof(DateTime));
 
 dt.Rows.Add("Newtonsoft.Json", "11.0.1", new DateTime(2018, 2, 17));
 dt.Rows.Add("NUnit", "3.9.0", new DateTime(2017, 11, 10));
 
 string json = JsonConvert.SerializeObject(dt, Formatting.Indented);
 
 Console.WriteLine(json);
 // [
 //   {
 //     "PackageId": "Newtonsoft.Json",
 //     "Version": "11.0.1",
 //     "ReleaseDate": "2018-02-17T00:00:00"
 //   },
 //   {
 //     "PackageId": "Newtonsoft.Json",
 //     "Version": "10.0.3",
 //     "ReleaseDate": "2017-06-18T00:00:00"
 //   }
 // ]

The other benefit of .NET Standard 2.0 is developers are no longer spammed with NuGet dependencies. UWP app authors for example saw NuGet pull in over 100 packages when referencing Json.NET. UWP supporting .NET Standard 2.0 and consuming a netstandard2.0 package eliminates that problem.

JsonConverter Stuff

Json.NET 11 adds a generic JsonConverter<T>. If you only care about serializing one specific type then JsonConverter<T> eliminates boiler plate code from your converter and keeps everything strongly typed.

Also new is a UnixDateTimeConverter. There is no standard for serializing dates in JSON and so UnixDateTimeConverter is a useful converter for anyone who want to store time as an integer Unix epoch in their JSON.

JSON Path Stuff

Json.NET 11 adds support for the regular expression operator in JSON Path queries. JSON Path has no formal specification (other than a blog post) but one common addition to it is support for querying with regular expressions.

JArray packages = JArray.Parse(@"[
   {
     ""PackageId"": ""Newtonsoft.Json"",
     ""Version"": ""11.0.1"",
     ""ReleaseDate"": ""2018-02-17T00:00:00""
   },
   {
     ""PackageId"": ""NUnit"",
     ""Version"": ""3.9.0"",
     ""ReleaseDate"": ""2017-11-10T00:00:00""
   }
 ]");
 
 List<JToken> newtonsoftPackages = packages.SelectTokens(@"$.[?(@.PackageId =~ /^Newtonsoft\.(.*)$/)]").ToList();
 
 Console.WriteLine(newtonsoftPackages.Count);
 // 1

JSON Path has also seen many smaller bug fixes this release to improve its performance and support of escaped characters.

And lots more

Serializing and deserializing enumerations by name is faster and more accurate, JsonReader.SupportMultipleContent supports reading multiple comma delimited fragments of JSON together, JObject exposes ContainsKey, error messages have improved in many exceptional situations, and dozens of other new features and bug fixes.

Changes

Here is a complete list of what has changed since Json.NET 10.0 Release 3.

New feature - Added netstandard2.0 build
New feature - Added generic JsonConverter<T>
New feature - Added UnixDateConverter for converting Unix timestaps
New feature - Added support for regex operator in JSON Paths
New feature - Added JsonObjectAttribute.ItemNullValueHandling
New feature - Added JsonObjectContract.ItemNullValueHandling
New feature - Improved performance when resolving serialization contracts by using ConcurrentDictionary
New feature - Improved performance of JToken.Path with a faster reverse
New feature - Improved performance of parsing Int32 JSON integer values
New feature - Improved performance of parsing and writing enum names
New feature - Added IgnoreIsSpecifiedMembers to DefaultContractResolver
New feature - Added IgnoreShouldSerializeMembers to DefaultContractResolver
New feature - Added support for reading multiple comma delimited values with JsonReader.SupportMultipleContent
New feature - Improved error message when an object is reused with PreserveReferencesHandling
New feature - Added IConvertible support to netstandard1.3
New feature - Added INotifyPropertyChanging support to netstandard1.3
New feature - Optimized internal buffering when writing very large strings
New feature - JObject.ContainsKey is now public
New feature - Improved the error message when serialized ByRef properties
New feature - Improved the error message when serializing FileInfo/DictionaryInfo without ISerializable
New feature - Improved the error message when failing conversion in JsonReader.ReadAsInt32 and JsonReader.ReadAsDecimal
New feature - Improved the error message when deserializing badly formatted regex strings
Change - Types that implement ISerializable but don't have [SerializableAttribute] are not serialized using ISerializable
Change - Changed JsonProperty.MemberConverter to obsolete
Change - Changed camel casing logic for all caps words to not leave last character capitalized
Change - Changed enum serialization in dictionary keys to use EnumMemberAttribute
Fix - Fixed converting default datetime in JSON to XML on netstandard1.3
Fix - Fixed deserializing ObservableCollection in .NET Core 2.0
Fix - Fixed incorrectly allowing static IsSpecified properties
Fix - Fixed not preserving trailing zeros when deserializing decimals
Fix - Fixed JValue.CompareTo with number and string values
Fix - Fixed not erroring when reading undefined for nullable long
Fix - Fixed serializing immutable collections when .NET 4.0 or previous Newtonsoft.Json assembly is GACed
Fix - Fixed writing null values by XmlNodeConverter and RegexConverter
Fix - Fixed deserializing with a TraceWriter when the reader is not at the start
Fix - Fixed TraceJsonWriter.WriteValue(object) writing value twice
Fix - Fixed deserializing with constructor and readonly collection property
Fix - Fixed error when writing unknown null value as JSON
Fix - Fixed merging null string values
Fix - Fixed missing CancellationToken usages in JsonTextWriter.WriteAsync
Fix - Fixed error with JsonSerializer.Populate and comments in JSON array
Fix - Fixed error handling when deserializing certain dictionary and lists
Fix - Fixed serializing collection that is nullable
Fix - Fixed JsonTextReader sync read in async method
Fix - Fixed JsonConverter not called when target type is list and token is a string
Fix - Fixed serializing a property that is defined in multiple interfaces
Fix - Fixed error when deserializing null value into ConcurrentDictionary
Fix - Fixed escaping special characters in generated JSON Paths
Fix - Fixed reading escaped special characters in JSON Paths
Fix - Fixed using extension data with dictionary that explicitly implements Add method
Fix - Fixed parsing enum name to exact casing value before falling back to case-insensitive value
Fix - Fixed DataContractAttribute not forcing object serialization of classes
Fix - Fixed bug when deserializing into existing non-IList collection
Fix - Fixed bug when deserializing into existing non-IDictionary collection
Fix - Fixed JsonReader.ReadAsInt32 with BigInteger values

Links

Json.NET GitHub Project

Json.NET 11.0 Release 1 Download - Json.NET source code and assemblies