Prevent unwanted headers when returning 304 Not Modified with ServiceStack

Question

Using ServiceStack, I just want to return 304 Not Modified as such:

HTTP/1.1 304 Not Modified

But ServiceStack adds many other unwanted (returning HttpResult with 304 code) headers as such:

HTTP/1.1 304 Not Modified
Content-Length: 0
Content-Type: application/json
Server: Microsoft-HTTPAPI/2.0
X-Powered-By: ServiceStack/3.94 Win32NT/.NET
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS
Access-Control-Allow-Headers: Content-Type
Date: Tue, 07 Aug 2012 13:39:19 GMT

How can I prevent the other headers from being outputted? I've tried various approaches with HttpResult, registering a dummy content type filter, but as its name implies only controls content, not the headers, or others listed here. I've also tried implementing my own IHttpResult derivative with IStreamWriter and IHasOptions with the same results: ServiceStack adds unwanted headers.

Thanks

Update

Was able to remove content-type by using the following, but some headers are still present i.e. content-length, server, and date.

    public override object OnGet(FaultTypes request)
    {
      var result = new HttpResult
      {
       StatusCode = HttpStatusCode.NotModified,
       StatusDescription = "Not Modified", // Otherwise NotModified written!
      };

      // The following are hacks to remove as much HTTP headers as possible
      result.ResponseFilter = new NotModifiedContentTypeWriter();
      // Removes the content-type header
      base.Request.ResponseContentType = string.Empty;

      return result;
    }

class NotModifiedContentTypeWriter : ServiceStack.ServiceHost.IContentTypeWriter
{
  ServiceStack.ServiceHost.ResponseSerializerDelegate ServiceStack.ServiceHost.IContentTypeWriter.GetResponseSerializer(string contentType)
  {
    return ResponseSerializerDelegate;
  }

  void ServiceStack.ServiceHost.IContentTypeWriter.SerializeToResponse(ServiceStack.ServiceHost.IRequestContext requestContext, object response, ServiceStack.ServiceHost.IHttpResponse httpRes)
  {
  }

  void ServiceStack.ServiceHost.IContentTypeWriter.SerializeToStream(ServiceStack.ServiceHost.IRequestContext requestContext, object response, System.IO.Stream toStream)
  {
  }

  string ServiceStack.ServiceHost.IContentTypeWriter.SerializeToString(ServiceStack.ServiceHost.IRequestContext requestContext, object response)
  {
    return string.Empty;
  }

  public void ResponseSerializerDelegate(ServiceStack.ServiceHost.IRequestContext requestContext, object dto, ServiceStack.ServiceHost.IHttpResponse httpRes)
  {
  }
}

score 8 · Accepted Answer · edited May 23 '17 at 10:34

8

The only headers emitted by ServiceStack are the ones registered in the EndpointHostConfig.GlobalResponseHeaders.

Remove them if you don't want them emitted, e.g:

SetConfig(new EndpointHostConfig { 
    GlobalResponseHeaders = new Dictionary<string,string>()
});

You can add them on an adhoc-basis using a HttpResult, e.g:

return new HttpResult(dto) {
    Headers = {
       { "Access-Control-Allow-Origin", "*" },
       { "Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS" } 
       { "Access-Control-Allow-Headers", "Content-Type" }, }
};

Both options explained in more detail at: servicestack REST API and CORS

edited May 23 '17 at 10:34

Community

1
1

answered Aug 07 '12 at 14:53

mythz

141,670
29
246
390

Thanks for the answer, but this only removes the CORS, not the others. I still have HTTP/1.1 304 Not Modified Content-Length: 0 Content-Type: application/json Expires: Thu, 16 Aug 2012 16:20:25 GMT Server: Microsoft-HTTPAPI/2.0 Date: Thu, 16 Aug 2012 16:20:24 GMT – Martin Tapp Aug 16 '12 at 16:21
The emitted headers that aren't in `GlobalResponseHeaders` or added yourself on a per-service basis with `HttpResult` are not from ServiceStack. IIS / ASP.NET may choose to add their own headers. – mythz Aug 16 '12 at 16:23
Not using IIS/ASP.Net, just console app test. Seems added from JSON serializer and others. How can I control these? – Martin Tapp Aug 16 '12 at 16:29
Nothing is added from any serializers. Are you sure you're setting `GlobalResponseHeaders = new Dictionary()`? This will remove the ServiceStack headers. I don't know how to remove the `Server` HTTP header that is added by HttpListener. – mythz Aug 16 '12 at 16:33
Yes, GlobalResponseHeaders is empty dictionary. Seems content-type and length are automatically added by JSON serializer, but no control over them... – Martin Tapp Aug 16 '12 at 16:35
Right `ContentLength` are added by ASP.NET/IIS when you write to the response stream. ServiceStack adds `Content-Type` as mandated by the HTTP Spec, there's an option to append `;charset=utf-8` with `Config.AppendUtf8CharsetOnContentTypes` but the header itself is controlled by the ContentType used, you can create your own at: http://www.servicestack.net/ServiceStack.Northwind/vcard-format.htm – mythz Aug 16 '12 at 17:07
HTTP spec says content-type is required by some status codes, not all. Tried using my own content type without success (differs from requested content and only controls response content i.e. not headers). What could I intercept in ServiceStack or ASP.NET/IIS to control http messages (header+content)? – Martin Tapp Aug 16 '12 at 17:13
If there's a response body, there should be a `Content-Type`. You can control it by returning `HttpResult` in service or you can also set it with `httpReq.ResponseContentType` - but the Content-Type is bound to the ContentType formatter. – mythz Aug 16 '12 at 17:22
No more `content-type`, but `content-length` is still written! – Martin Tapp Aug 16 '12 at 19:29

score 0 · Answer 2 · answered May 28 '14 at 19:49

0

Actually you can just do something like this in your API

base.Response.StatusCode = (int) HttpStatusCode.NotModified;
base.Response.EndHttpRequestWithNoContent();
return new HttpResult();

Which would not return ContentType, ContentLength, etc

answered May 28 '14 at 19:49

Frosty

1

Prevent unwanted headers when returning 304 Not Modified with ServiceStack

2 Answers2