JSON Merge Patch support for ASP.NET Core

- Morcatko.AspNetCore.JsonMergePatch (ASP.NET Core 2.x)
- Morcatko.AspNetCore.JsonMergePatch.NewtonsoftJson (ASP.NET Core 3.x)
- Morcatko.AspNetCore.JsonMergePatch.SystemText (ASP.NET Core 3.x)
- Morcatko.AspNetCore.JsonMergePatch.Document (ASP.NET Core 3.x - base package)

JSON Merge Patch

• RFC 7396
• performs partial resource update similar to JSON Patch
• Supports Swagger
• netstandard 2.0

C# object:
var backendModel = new Model()
{
    Name = "James Bond"
    Age = "45"
    Weapon = "Gun"
}

JSON Merge Patch:
{
    "Weapon": "Knife"
}

resulting C# object:
{
    Name = "James Bond"
    Age = "45"
    Weapon = "Knife"
}

How to

See 2.1-testApp or 3.0 testApp for sample

1. Install nuget.

• ASP.NET Core 2.x Morcatko.AspNetCore.JsonMergePatch
• ASP.NET Core 3.x (Newtonsoft.Json) Morcatko.AspNetCore.JsonMergePatch.NewtonsoftJson
• ASP.NET Core 3.x (System.Text) Morcatko.AspNetCore.JsonMergePatch.SystemText nuget

2. Add to your startup class

using Morcatko.AspNetCore.JsonMergePatch;

public void ConfigureServices(IServiceCollection services)
{
    ...
    services
        .AddMvc()                         // or .AddMvcCore()
        //.AddJsonMergePatch();           // 2.x
        //.AddNewtonsoftJsonMergePatch(); // 3.x (Newtonsoft.Josn)
        //.AddSystemTextJsonMergePatch(); // 3.x (System.Text)
    ...
}

3. Use in your controller

using Morcatko.AspNetCore.JsonMergePatch;

[HttpPatch]
[Consumes(JsonMergePatchDocument.ContentType)]
public void Patch([FromBody] JsonMergePatchDocument<Model> patch)
{
    ...
    patch.ApplyTo(backendModel);
    ...
}

You can apply a patch to a different Type (be carefull, all C# static typing is ignored) - see #16 for more details.

BackendModel backendModel;
JsonMergePatch<DtoModel> patch;
patch.ApplyToT(backendModel)

4. Swagger config (optional)

copy & paste this class into your app

• 2.x - https://github.com/Morcatko/Morcatko.AspNetCore.JsonMergePatch/blob/master/src/2.1-testApp/JsonMergePatchDocumentOperationFilter.cs
• 3.x - https://github.com/Morcatko/Morcatko.AspNetCore.JsonMergePatch/blob/master/src/3.0-testApp/JsonMergePatchDocumentOperationFilter.cs

services.AddSwaggerGen(c =>
    {
        c.OperationFilter<JsonMergePatchDocumentOperationFilter>();
    });

Options

    services
        .AddMvc()
        .AddJsonMergePatch(o => ....)

• bool EnableDelete - Deletes items when target object is Dictionary and patched value is null

How to - unit testing

See tests in ...Builder.Json.Simple class for more examples

Morcatko.AspNetCore.JsonMergePatch.Tests.Builder.Json

public void UnitTest()
{
    var model = new Model();
    var patch1 = PatchBuidler.Build<Model>("{ integer: 1}");
    ...
    or
    ...
    var original = new Model();
    var patched = new Model() { Integer = 1};
    var patch2 = PatchBuilder.Build(original, patched);
}

Known issues/Not working

• ModelState.IsValid is false when a required property is missing
• Enums with [EnumMember(Value = "....")] attribute