How can I return json from my WCF rest service (.NET 4), using Json.Net, without it being a string, wrapped in quotes?

Question

UPDATE 10/19/2010 I know I asked this question a while ago, but the workarounds shown in these answers are hardly satisfactory, and this is still a common p

Answer 1

It seems to me that you use not correct DataContractJsonSerializer. What is strange is: you don't define ResponseFormat = ResponseFormat.Json attribute for the public SimpleMessage SayHelloObject() method.

Moreover if you have {"Message":"Hello World"} in a string and display it in debugger it will be display as "{\"Message\":\"Hello World\"}", so exactly like you see string json = JsonConvert.Serialize(message); (Json.Net). So it seems to me that you have in both cases the same results.

To verify this use a client software which read the results. See some examples

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UPDATED: In your code you define method SayHelloString(). It's result are a string. If you call the method this string will be one more time JSON serialized. JSON serialization of the string {"Message":"Hello World"} is a quoted string (see http://www.json.org/ definition for not a object, but a string) or exactly string "{\"Message\":\"Hello World\"}". So everything is correct with both methods of your Web Service.

UPDATED 2: I am glad that my tip from "Update" part of my answer helped you to swich of the double JSON serialization.

Nevertheless I would recommend you to change a little the solution to stay more at the WCF concept.

If you want implement a custom encoding of the web responce in WCF (see http://msdn.microsoft.com/en-us/library/ms734675.aspx) your WCF method should better return Message instead of void:

[WebGet(UriTemplate = "hello")]
public Message SayHello()
{
    SimpleMessage message = new SimpleMessage() {Message = "Hello World"};
    string myResponseBody = JsonConvert.Serialize(message);
    return WebOperationContext.Current.CreateTextResponse (myResponseBody,
                "application/json; charset=utf-8",
                Encoding.UTF8);
}

You can of cause use another Message formater: for example CreateStreamResponse (or some other see http://msdn.microsoft.com/en-us/library/system.servicemodel.web.weboperationcontext_methods(v=VS.100).aspx) instead of CreateTextResponse. If you want to set some additional HTTP headers or Http status code (for example in case of some error) you can do this with this way:

OutgoingWebResponseContext ctx = WebOperationContext.Current.OutgoingResponse;
ctx.StatusCode = HttpStatusCode.BadRequest;

At the end I want repeat my question from a comment: could you explain why you want use Json.Net instead of DataContractJsonSerializer? Is it performance improvement? Do you need implement serialization of some data types like DateTime in other way as DataContractJsonSerializer do? Or the main reason of your choose of Json.Net is some other?