Json.NET 4.5 Release 11 - Serialization Tracing

Serialization Tracing

The major new feature this release is serialization tracing. Using the ITraceWriter interface you can log and debug what is happening inside the Json.NET serializer when serializing and deserializing JSON.

Staff staff = new Staff();
staff.Name = "Arnie Admin";
staff.Roles = new List<string> { "Administrator" };
staff.StartDate = DateTime.Now;
 
ITraceWriter traceWriter = new MemoryTraceWriter();
 
JsonConvert.SerializeObject(
  staff,
  new JsonSerializerSettings { TraceWriter = traceWriter, Converters = { new JavaScriptDateTimeConverter() } });
 
Console.WriteLine(traceWriter);
// 2012-11-11T12:08:42.761 Info Started serializing Newtonsoft.Json.Tests.Serialization.Staff. Path ''.
// 2012-11-11T12:08:42.785 Info Started serializing System.DateTime with converter Newtonsoft.Json.Converters.JavaScriptDateTimeConverter. Path 'StartDate'.
// 2012-11-11T12:08:42.791 Info Finished serializing System.DateTime with converter Newtonsoft.Json.Converters.JavaScriptDateTimeConverter. Path 'StartDate'.
// 2012-11-11T12:08:42.797 Info Started serializing System.Collections.Generic.List`1[System.String]. Path 'Roles'.
// 2012-11-11T12:08:42.798 Info Finished serializing System.Collections.Generic.List`1[System.String]. Path 'Roles'.
// 2012-11-11T12:08:42.799 Info Finished serializing Newtonsoft.Json.Tests.Serialization.Staff. Path ''.

Json.NET has two implementations of ITraceWriter: MemoryTraceWriter which keeps messages in memory for simple debugging like the example above, and DiagnosticsTraceWriter which writes messages to any System.Diagnostics.TraceListeners your application is using.

To write messages using your existing logging framework implement a custom version of ITraceWriter.

Read more about trace writing here: Debugging with Serialization Tracing

JSON String Escaping

By default Json.NET only escapes control characters like new line when serializing text. New in this release is the StringEscapeHandling property on JsonTextWriter. Using StringEscapeHandling you can choose to escape HTML characters (<, >, &, ', ") or escape all non-ASCII characters.

JToken.ToObject Performance

The LINQ to JSON JToken class has a ToObject method on it for converting the JSON token to a .NET type. In previous versions of Json.NET this method always used the JsonSerializer behind the scenes to do the conversion which was unnecessary for converting simple types like strings, numbers, booleans, dates, etc.

Json.NET 4.5 Release 11 now checks whether the object being converted to is a simple type and if so it skips using the JsonSerializer. The end result is ToObject is now 400% faster for most types.

Changes

Here is a complete list of what has changed since Json.NET 4.5 Release 10.

  • New feature - Added ITraceWriter, MemoryTraceWriter, DiagnosticsTraceWriter
  • New feature - Added StringEscapeHandling with options to escape HTML and non-ASCII characters
  • New feature - Added non-generic JToken.ToObject methods
  • New feature - Deserialize ISet<T> properties as HashSet<T>
  • New feature - Added implicit conversions for Uri, TimeSpan, Guid
  • New feature - Missing byte, char, Guid, TimeSpan and Uri explicit conversion operators added to JToken
  • New feature - Special case so Version type is correctly deserialized
  • Change - Silverlight and Windows Phone assemblies in NuGet are strong named again
  • Change - Improved CamelCasePropertyNamesContractResolver camel casing property names
  • Change – Explicit JValue conversions are more flexible when converting values
  • Fix - Fixed QuoteChar not being used when writing DateTimes, TimeSpans, Uris and Guids
  • Fix - Fixed JValue constructors for Uri, TimeSpan, Guid assigning incorrect JTokenType
  • Fix - Fixed ReferenceLoopHandling not being used when serializing ISerializable and dynamic values
  • Fix - Fixed potential null reference error when getting attributes
  • Fix - Fixed .NET 2.0 build incorrectly referencing DateTimeOffset

Links

Json.NET CodePlex Project

Json.NET 4.5 Release 11 Download – Json.NET source code and assemblies

XAML Applications on Windows 8 with DXTREME

XAML Applications on Windows 8 with DXTREME

The public release date of Windows 8 is rapidly approaching and with it comes a brand new way to build and sell Windows applications via the new Windows Store.

I first used the new Windows Store platform earlier this year when I ported my open source Json.NET library to it, and since then I have also built a couple Windows applications on it using JavaScript. In this blog post I am trying out something new to me for the first time: Windows 8 development using .NET and XAML with DXTREME’s XAML controls.

Installation and first impressions

The first thing you’ll notice after downloading DXTREME is its installer. The design is simple and to the point, and it looks completely at home in the Windows 8 UI.

Installer8

After installation is complete you are presented with a dialog that serves as a hub to developers getting started with DXTREME. The dialog links to two Visual Studio solutions: a demo application that shows off the Windows 8 XAML controls that come with the library, and a solution application that shows the controls used together in a great looking professionally designed Windows 8 app.

Launcher6

As someone completely new to DXTREME and Windows 8 XAML development I found both of these applications and their source code to be great resources when building my first Windows Store XAML app. Especially useful was a feature of the demo application that lets you view the source code for a control while the demo is running.

Getting Started

I find the best way to learn something new is to make something with it. The Windows 8 application I’m going to step through making in this blog post is called /r/Imgur and is an app that integrates the popular social websites Reddit and Imgur. It displays images from those websites within a Windows application. (a link to the final source code will be at the end of the blog post)

newproject6

As part of its installation DXTREME adds new Windows 8 project types to Visual Studio 2012. I used the DXTREME Grid Application project which sets up a basic Windows 8 tile based UI for you using DXTREME’s new controls.

Fetching Data from Imgur

The application’s data and images are driven from Imgur, an Internet image hosting service. They provide a simple API for getting album information as JSON for their website.

public static async Task<Album> LoadAlbum(string subReddit)
{
    Album album = new Album();
    album.Title = subReddit;
 
    HttpClient httpClient = new HttpClient();
    string json = await httpClient.GetStringAsync("http://imgur.com" + subReddit + "/top.json");
 
    JObject o = JObject.Parse(json);
    foreach (JToken i in o["data"])
    {
        Image image = i.ToObject<Image>();
        image.Album = album;
        image.ImageUrl = string.Format("http://i.imgur.com/{0}.jpg", image.Hash);
 
        album.Items.Add(image);
    }
 
    return album;
}

The code above utilizes the Web API Client library and Json.NET. It simply gets the album data as JSON and deserializes it to an Album object. These albums and their images are what the UI databinds to.

Styling the UI

Two of XAML’s most powerful features are its support for the model-view-view-model pattern (MVVM) and design time view data, both of which have great support in DXTREME. Once setup design time view data lets you style your Windows 8 application from within Visual Studio 2012 or Expression Blend against pretend data. You no longer need to constantly restart your application to see what the final result will be because it is instantly visible in the XAML designer. It’s a great timesaver.

blend8

The screenshot above is /r/Imgur in Expression Blend after I have finished styling it. The controls are being databound to hardcoded view model of Albums that I have created so that the look of the final application is visible in the Blend and Visual Studio designers without having to call off to the Imgur API.

Adding New Albums

As well as displaying some pre-set albums in the app we want to give users the ability to add new albums. To do this we’ll add a Windows 8 appbar button that will launch a Windows 8 style dialog with fields for the user to enter the new album name. Fortunately DXTREME has a Windows 8 style dialog that is perfect for the task.

<Page.Resources>
    <DataTemplatex:Key="AddAlbumTemplate">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinitionWidth="Auto" />
                <ColumnDefinition />
            </Grid.ColumnDefinitions>
            <TextBlockText="/r/"FontSize="18"VerticalAlignment="Center" />
            <TextBoxGrid.Column="1"Text="{Binding Path=Title, Mode=TwoWay}"BorderThickness="1"BorderBrush="#FF3D3D3D"Margin="5 0 0 0" />
        </Grid>
    </DataTemplate>
</Page.Resources>
<dxcore:Interaction.Behaviors>
    <dxcore:ServiceContainerBehaviorServicesClient="{Binding}">
        <dxcore:DialogServiceKey="addDialog"ContentTemplate="{StaticResource AddAlbumTemplate}"Buttons="OKCancel"DefaultDialogButton="OK"CancelDialogButton="Cancel"Title="Add Reddit Album"/>
    </dxcore:ServiceContainerBehavior>
</dxcore:Interaction.Behaviors>

Wiring up a DialogService to a DataTemplate using the code above lets you launch a dialog without having to worry about recreating the look and feel of a Windows 8 dialog; that’s all handled for you by the dialog control.

Album Rating

The final piece to the application is to add the album rating to its detail page. Here we’ll add a pie graph using DXTREME’s graphing library to display the ratio of user up votes to down votes for the album.

chart5

The look and behaviour of the pie graph is defined in XAML, allowing us to design it inside the Visual Studio XAML designer without running the application, and then the up and down votes for the album are databound the graph when the application executed at runtime.

Wrapping Up

I found the controls I used while making /r/Imgur well thought out and easy to use. One important feature I always look for in controls and libraries when using XAML is how well they work with the rest of the framework. Everything has great MVVM support and the controls included in the library provide a nice experience to work with the Visual Studio 2012 and Expression Blend designers.

Click here to download the /r/Imgur application source code

 

 

Disclosure of Material Connection: I received one or more of the products or services mentioned above for free in the hope that I would mention it on my blog. Regardless, I only recommend products or services I use personally and believe my readers will enjoy. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

Json.NET 4.5 Release 10 – Portable Class Library on NuGet

Json.NET's major new feature this release is the portable class library assembly is available over NuGet. This is made possible by NuGet 2.1 supporting portable class libraries. Read more about NuGet 2.1 here.

Case insensitive JObject GetValue and TryGetValue

To simplify getting property values without worrying about the property name's case a couple of helper methods have been added to JObject. GetValue and TryGetValue will first attempt to get a property value with the exact case after which it will ignore case and the first matching property will be returned.

JObject o = JObject.Parse(@"{
  'name': 'Lower',
  'NAME': 'Upper'
}");
 
string exactMatch = (string)o.GetValue("NAME", StringComparison.OrdinalIgnoreCase);
// Upper
 
string ignoreCase = (string)o.GetValue("Name", StringComparison.OrdinalIgnoreCase);
// Lower

In this example the first call to GetValue with "NAME" exactly matches the second property. The second call to GetValue with "Name" doesn’t exactly match any of the properties so a case insensitive search is made and the first property is returned.

Changes

Here is a complete list of what has changed since Json.NET 4.5 Release 9.

  • New feature - Added Portable build to NuGet package
  • New feature - Added GetValue and TryGetValue with StringComparison to JObject
  • Change - Improved duplicate object reference id error message
  • Fix - Fixed error when comparing empty JObjects
  • Fix - Fixed SecAnnotate warnings
  • Fix - Fixed error when comparing DateTime JValue with a DateTimeOffset JValue
  • Fix - Fixed serializer sometimes not using DateParseHandling setting
  • Fix - Fixed error in JsonWriter.WriteToken when writing a DateTimeOffset
  • Fix - Fixed error when serializing emitted classes that have null constructor parameter names
  • Fix - Fixed empty strings not correctly deserializing as null onto nullable properties

Links

Json.NET CodePlex Project

Json.NET 4.5 Release 10 Download – Json.NET source code and assemblies

Json.NET vs Windows.Data.Json

Windows 8 introduces a new way to work with JSON via the Windows.Data.Json namespace. Similar to LINQ to JSON in Json.NET it defines classes that can be used to parse values, strings, objects, and arrays from JSON text or serialize value types into JSON text.

Below is a comparison of Json.NET’s LINQ to JSON to Window 8’s Windows.Data.Json.

Creating JSON

The big difference between the two libraries when creating JSON is Windows.Data.Json requires string/integer/double values to be explicitly converted to JsonValue objects.

Note that there is a weird limitation to creating JSON with Windows.Data.Json: it doesn’t allow you to set properties to null or have null array values.

// Windows.Data.Json
// -----------------
JsonObject jsonObject = new JsonObject
  {
    {"CPU", JsonValue.CreateStringValue("Intel")},
    {"Drives", new JsonArray {
        JsonValue.CreateStringValue("DVD read/writer"),
        JsonValue.CreateStringValue("500 gigabyte hard drive")
      }
    }
  };
string json1 = jsonObject.Stringify();
 
// LINQ to JSON
// ------------
JObject jObject = new JObject
  {
    {"CPU", "Intel"},
    {"Drives", new JArray {
        "DVD read/writer",
        "500 gigabyte hard drive"
      }
    }
  };
string json2 = jObject.ToString();

Querying JSON

Windows.Data.Json requires a value to be cast to its exact type with the GetObject/GetArray methods before it can be used, making Windows.Data.Json’s code verbose compared to LINQ to JSON.

string json = @"{
  ""channel"": {
    ""title"": ""James Newton-King"",
    ""link"": ""http://james.newtonking.com"",
    ""description"": ""James Newton-King's blog."",
    ""item"": [
      {
        ""title"": ""Json.NET 1.3 + New license + Now on CodePlex"",
        ""description"": ""Annoucing the release of Json.NET 1.3, the MIT license and the source being available on CodePlex"",
        ""link"": ""http://james.newtonking.com/projects/json-net.aspx"",
        ""category"": [
          ""Json.NET"",
          ""CodePlex""
        ]
      }
    ]
  }
}";
 
// Windows.Data.Json
// -----------------
JsonObject jsonObject = JsonObject.Parse(json);
string itemTitle1 = jsonObject["channel"].GetObject()["item"].GetArray()[0].GetObject()["title"].GetString();
 
// LINQ to JSON
// ------------
JObject jObject = JObject.Parse(json);
string itemTitle2 = (string)jObject["channel"]["item"][0]["title"];

Performance

Json.NET is slightly slower at writing JSON than Windows.Data.Json but considerably faster parsing.

Things aren’t as happy as they used to be down here at the unemployment office. Joblessness is no longer just for philosophy majors. Useful people are starting to feel the pinch.

Converting Between LINQ to JSON and Windows.Data.Json

Json.NET supports converting between the types of the two libraries. Use FromObject to convert a Windows.Data.Json value to LINQ to JSON and use ToObject to convert LINQ to JSON to Windows.Data.Json.

JsonObject jsonObject = new JsonObject
  {
    {"CPU", JsonValue.CreateStringValue("Intel")},
    {"Drives", new JsonArray {
        JsonValue.CreateStringValue("DVD read/writer"),
        JsonValue.CreateStringValue("500 gigabyte hard drive")
      }
    }
  };
 
// convert Windows.Data.Json to LINQ to JSON
JObject o = JObject.FromObject(jsonObject);
 
// convert LINQ to JSON to Windows.Data.Json
JArray a = (JArray)o["Drives"];
JsonArray jsonArray = a.ToObject<JsonArray>();