Put content in HttpResponseMessage object?

Question

Several months ago, Microsoft decided to change up the HttpResponseMessage class. Before, you could simply pass a data type into the constructor, and then return the message with that data, but not anymore.

Now, you need to use the Content property to set the content of the message. The problem is that it is of type HttpContent, and I can't seem to find a way to convert a string, for example, to HttpContent.

Does anyone know how to deal with this issue? Thanks a lot.

score 267 · Answer 1 · answered Sep 03 '12 at 01:04

267

For a string specifically, the quickest way is to use the StringContent constructor

response.Content = new StringContent("Your response text");

There are a number of additional HttpContent class descendants for other common scenarios.

answered Sep 03 '12 at 01:04

Jim O'Neil

23,344
7
42
67

See my post below for creating your own derived types of StringContent (e.g. JSON, XML etc.). – bytedev Jan 13 '16 at 16:52

score 147 · Answer 2 · edited Oct 03 '18 at 12:12

147

You should create the response using Request.CreateResponse:

HttpResponseMessage response =  Request.CreateResponse(HttpStatusCode.BadRequest, "Error message");

You can pass objects not just strings to CreateResponse and it will serialize them based on the request's Accept header. This saves you from manually choosing a formatter.

edited Oct 03 '18 at 12:12

Kols

3,641
2
34
42

answered May 21 '13 at 19:33

Florin Dumitrescu

8,182
4
33
29

It automatically works with the content types so you can do xml/json without extra code – Apr 13 '16 at 10:08
I think it would be more correct to call `CreateErrorResponse()` if the response is an error, as it is in this answer's example. Inside my try-catch I'm using: `this.Request.CreateErrorResponse(HttpStatusCode.InternalServerError, "message", exception);` And, this is the correct answer if you're at all concerned about respecting the caller's Accept header, without extra shenanigans.(and you're using WebAPI) – JMD Nov 21 '16 at 23:56
4

@FlorinDumitrescu His point was that this ONLY works for when you inherit `ApiController`. If you are only inheriting `Controller` instead, it doesn't work, and you have to create it yourself: `HttpResponseMessage msg = new HttpResponseMessage(); msg.Content = new StringContent("hi"); msg.StatusCode = HttpStatusCode.OK;` – vapcguy Mar 26 '18 at 23:32

score 77 · Accepted Answer · edited Jun 10 '19 at 15:18

77

Apparently the new way to do it is detailed here:

http://aspnetwebstack.codeplex.com/discussions/350492

To quote Henrik,

HttpResponseMessage response = new HttpResponseMessage();

response.Content = new ObjectContent<T>(T, myFormatter, "application/some-format");

So basically, one has to create a ObjectContent type, which apparently can be returned as an HttpContent object.

edited Jun 10 '19 at 15:18

BurnsBA

4,347
27
39

answered Sep 03 '12 at 00:09

praetor

3,195
2
23
21

1

@user1760329 it would be a `new JsonMediaTypeFormatter();` or similar depending on your format – John Nov 17 '14 at 19:05
2

`ObjectContent` is not found, using WCF – Medet Tleukabiluly Nov 25 '14 at 04:46
2

I wouldn't qualify this as the "new way to do it" - that article you reference lists it as an alternative in the event you want to have "complete control of the [media-type] formatter you want to use" – Bern Apr 23 '15 at 13:13
Thanks @praetor. This has been really helpful to me – Rashmi Pandit Feb 25 '16 at 04:43

score 76 · Answer 4 · edited Oct 24 '17 at 12:10

76

The easiest single-line solution is to use

return new HttpResponseMessage( HttpStatusCode.OK ) {Content =  new StringContent( "Your message here" ) };

For serialized JSON content:

return new HttpResponseMessage( HttpStatusCode.OK ) {Content =  new StringContent( SerializedString, System.Text.Encoding.UTF8, "application/json" ) };

edited Oct 24 '17 at 12:10

Igor Monteiro

933
1
11
29

answered Dec 10 '16 at 13:52

Simon Mattes

4,866
2
33
53

this didn't work for me because IHttpActionResult requires return type of ResponseMessageResult. See my answer below for what I ended up with. Also note, I did factor in nashawn's JsonContent (as derived from StringContent base class). – Adam Cox Apr 03 '17 at 15:35
2

Just wrap the HttpResponseMessage then: return new ResponseMessageResult( return new HttpResponseMessage( HttpStatusCode.OK ) { new StringContent( "Your message here" ) } ); **:)** – Simon Mattes Apr 04 '17 at 18:29

score 42 · Answer 5 · answered Feb 21 '14 at 13:42

42

For any T object you can do:

return Request.CreateResponse<T>(HttpStatusCode.OK, Tobject);

answered Feb 21 '14 at 13:42

ScubaSteve

7,724
8
52
65

6

Except `Request` is only available with a `CreateResponse` method if you are inheriting `ApiController`. It will not work if using `Controller`. – vapcguy Mar 26 '18 at 23:35

bytedev · Answer 6 · 2023-01-03T01:54:34.013

You can create your own specialised content types and then assign them to the HttpResponseMessage.Content property.

For example below one for JSON content and one for XML content:

public class JsonContent : StringContent
{
    public JsonContent(string content)
        : this(content, Encoding.UTF8)
    {
    }

    public JsonContent(string content, Encoding encoding)
        : base(content, encoding, "application/json")
    {
    }
}

public class XmlContent : StringContent
{
    public XmlContent(string content) 
        : this(content, Encoding.UTF8)
    {
    }

    public XmlContent(string content, Encoding encoding)
        : base(content, encoding, "application/xml")
    {
    }
}

very neat and clean implementation. – Sam Oct 26 '16 at 04:19 — Sam, Oct 26 '16 at 04:19

score 7 · Answer 7 · edited May 26 '22 at 20:26

Inspired by Simon Mattes' answer, I needed to satisfy the IHttpActionResult required return type of ResponseMessageResult. Also using nashawn's JsonContent, I made this :

return new System.Web.Http.Results.ResponseMessageResult(
    new System.Net.Http.HttpResponseMessage(System.Net.HttpStatusCode.OK)
    {
        Content = new JsonContent(JsonConvert.SerializeObject(contact, Formatting.Indented))
    });

See nashawn's answer for JsonContent.

score -2 · Answer 8 · edited Jun 07 '17 at 21:44

-2

No doubt that you are correct Florin. I was working on this project, and found that this piece of code:

product = await response.Content.ReadAsAsync<Product>();

Could be replaced with:

response.Content = new StringContent(string product);

edited Jun 07 '17 at 21:44

jmeinlschmidt

1,446
2
14
33

answered Jun 07 '17 at 20:04

Steven W. H.

7

3

This answer does not seem relevant to the question and does not show how to go from an object (Product) to a string – mageos Dec 14 '18 at 21:58

Put content in HttpResponseMessage object?

8 Answers8

Linked