Can I manually hard code a JSON object to be returned by ASP.NET web API?

Question

I'm used to doing this in Django (similar to Ruby on Rails) where in some cases I need to hard code a JSON response object for the client to be able to interpret, but I've been searching everywhere online on figuring out how to do this with ASP.NET web API and I can't find anything on this, ASP.NET web API seems to be forcing me to create a class to represent a JSON response for every URI controller.

For example, here's the only way I know for manually creating a JSON response:

1.) I first need to create the class to represent the response object

public class XYZ_JSON
{
    public string PropertyName { get; set; }
    public string PropertyValue { get; set; }
}

2.) Then I need to properly write up the URI controller that'll return an "XYZ_JSON" that I've just defined above:

// GET: api/ReturnJSON
public XYZ_JSON Get()
{
    XYZ_JSON test = new XYZ_JSON { PropertyName = "Romulus", PropertyValue = "123123" };

    return test;
}

Will result with an http response of something like:

200 OK {"PropertyName":"Romulus", "PropertyValue":"123123"}

This whole class to JSON design pattern is cool and all, but it's not helpful and actually makes things much worse when trying to return a class as a JSON object with many classes within it such as:

public class XYZ_JSON
{
    public string PropertyName { get; set; }
    public string PropertyValue { get; set; }
    public List<ComplexObject> objects { get; set; } // <- do not want
}

The JSON response object above isn't that complex, but for what I'm trying to accomplish I'll have to put a list of classes within a list of classes within a list of classes, and I can't develop it in this awkward way unless I spend a week on it which is just ridiculous.

I need to be able to return a JSON response in this kind of fashion:

// GET: api/ReturnJSON
public JSON_Response Get(string id)
{
    // do some SQL querying here to grab the model or what have you.

    if (somethingGoesWrong = true)
    return {"result":"fail"}
    else
    return {"result":"success","value":"some value goes here"}
}

The design pattern above is what I'm trying to accomplish with ASP.NET web API, a very simply way to return a semi-hard coded JSON response object which would allow me to return very unique and dynamic responses from a single URI. There's going to be many use cases where a list of up to 8 completely unique Class objects will be returned.

Also, If what I'm trying to accomplish is the backwards way of doing things than that's fine. I've released a very successful and stable iOS application with a flawless Django backend server handling things this way perfectly without any issues.

Can someone explain to me how I can return a simple hard coded JSON response using the ASP.NET web API?

Thanks!

Answer 1

Yes, you can manually hard-code a JSON object, using the System.Text.Json.Nodes class introduced in C# 6.0.

The following code isn't beautiful, but it should show you the functions you need to use. Note that you can't create JsonNodes directly, although you can create Objects, Arrays, and Values. If you've got a complex data structure, you can build these calls and objects into multiple functions just like all the rest of your C#, depending on how "hard" you mean when you say "hard code". I guess I'd call this process "manual" rather than hard-coded.

The JSON is sent across as text, so as usual you'll need a JSON.parse(response) call in your receiving page's JavaScript to decode the string into a JS object.

[HttpPost]
public JsonResult AjaxPostFunction(string yarp)
{
    var jo = new JsonObject();
    jo.Add("response", JsonValue.Create(yarp));
    var j1 = new JsonObject();
    j1.Add("value", JsonValue.Create("text"));
    j1.Add("num", JsonValue.Create(12));
    var j2 = new JsonObject();
    j2.Add("value", JsonValue.Create("string"));
    j2.Add("num", JsonValue.Create(3.14159265358979323));
    var ja = new JsonArray();
    ja.Add(j1);
    ja.Add(j2);
    jo.Add("test", ja);
    return Json(jo);
}

Answer 2

// GET: api/ReturnJSON
public JsonResult Get()
{
   return Json(new { Property1 = "Value1", Property2 = "Value2" });
}

You can return json using JsonResult class. and the Json() method takes anonymous object so you don't need to create a class.

Answer 3

For hard coded response, why not just do something like below. The JSON content will be returned without being surrounded by quotation marks.

    public HttpResponseMessage Get()
    {
        string content = "Your JSON content";
        return BuildResponseWithoutQuotationMarks(content);
    }

    private HttpResponseMessage BuildResponseWithoutQuotationMarks(string content)
    {
        var response = Request.CreateResponse(HttpStatusCode.OK);
        response.Content = new StringContent(content);
        return response;
    }

    private HttpResponseMessage BuildResponseWithQuotationMarks(string content)
    {
        var response = Request.CreateResponse(HttpStatusCode.OK, content);
        return response;
    }

Answer 4

You can create anonymous types in C#, so you can use one of these to produce your hard-coded result. For example:

return new JsonResult
{
    Data = new
    {
        result = "success",
        value = "some value"
    }
};

To clarify, the above code is for ASP.NET MVC. If you're using Web API, then you can just return the data object, or use an IHttpActionResult. The anonymous type part (the new {}) stays the same.

Answer 5

You can use a generic JObject to return your values without constructing a complete class structure as shown below

public JObject Get(int id)
    {

        return JsonConvert.DeserializeObject<JObject>(@"{""result"":""success"",""value"":""some value goes here""}");


    }

Answer 6

Use an anonymous object.

public object Get(string id)
{
    // do some SQL querying here to grab the model or what have you.

    if (somethingGoesWrong = true)
    return new {result = "fail"}
    else
    return new {result = "success", value= "some value goes here"}
}