The Umbraco /Base system is great for creating simple REST-like services. You can use the RestExtensionMethod attribute to instruct Umbraco to return your response as XML or not. But what is “not”? Apparently it means set Response.ContentType to “text/html”. But what if the returned data should be sent using a different mime type? Setting the ContentType manually like

HttpContext.Current.Response.ContentType = "application/json"

will not do the trick. Umbraco /Base will override it with “text/html” if you are returning a string from your service method.

What you need to do is to change your method return signature to “void” and write your data directly to the HttpResponse, like:

HttpContext.Current.Response.ContentType = "application/json";
HttpContext.Current.Response.Write(stringWriter.ToString());

Umbraco will not override the content type for “void”-methods. Below is a full example.

[RestExtension("Member")]
public class MemberService
{
	[RestExtensionMethod(returnXml = false, allowAll = true)]
	public static void Json()
	{
		var json = "{ \"firstName\": \"John\", \"lastName\": \"Smith\", \"age\": 25 }";

		// Write response and set content type
		HttpContext.Current.Response.ContentType = "application/json";
		HttpContext.Current.Response.Write(json);
	}
}