How to get HttpClient Json serializer to ignore null values

Question

I'm currently working with a console app which I'm using the HttpClient to interact with an Apache CouchDB database. I'm using this article: http://www.asp.net/web-api/overview/web-api-clients/calling-a-web-api-from-a-net-client

I'd like to ignore the null properties in my class when I'm serializing and sending a document to my database via the PostAsJsonSync but I'm not sure how:

public static HttpResponseMessage InsertDocument(object doc, string name, string db)
    {
      HttpResponseMessage result;
      if (String.IsNullOrWhiteSpace(name)) result = clientSetup().PostAsJsonAsync(db, doc).Result;
      else result = clientSetup().PutAsJsonAsync(db + String.Format("/{0}", name), doc).Result;
      return result;
    }

    static HttpClient clientSetup()
    {
      HttpClientHandler handler = new HttpClientHandler();
      handler.Credentials = new NetworkCredential("**************", "**************");
      HttpClient client = new HttpClient(handler);
      client.BaseAddress = new Uri("*********************");
      //needed as otherwise returns plain text
      client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
      return client;
    }

Here's the class I'm serializing....

class TestDocument
  {
    public string Schema { get; set; }
    public long Timestamp { get; set; }
    public int Count { get; set; }
    public string _rev { get; set; }
    public string _id { get; set; } - would like this to be ignored if null
  }

Any help much appreciated.

Behind the scenes, you are likely using Json.NET. http://stackoverflow.com/questions/9819640/json-net-ignoring-null-fields — Christopher Stevenson, Mar 02 '13 at 20:39
Looks exactly like my problem when doing put documents to CouchDB — Thomas, Jan 15 '18 at 12:55

Julien Jacobs · Accepted Answer · 2013-03-02T21:42:18.653

15

Assuming that you are using Json.NET to serialize your object, you should use the NullValueHandling property of the JsonProperty attribute

[JsonProperty(NullValueHandling=NullValueHandling.Ignore)]

Check out this great article and the online help for more details

edited Mar 02 '13 at 21:42

answered Mar 02 '13 at 20:43

Julien Jacobs

2,561
1
24
34

this will ignore it completely though, even if it later is no longer null – James Mundy Mar 02 '13 at 21:30
Right...changed the answer accordingly as JsonIgnore is indeed to not serialize a property – Julien Jacobs Mar 02 '13 at 21:43
1

This looks promising but for some reason it is still not ignoring the null values even though it should! – James Mundy Mar 02 '13 at 21:46
It works, it was an error on my part - I will mark this as the correct answer as it involves changing the least code. – James Mundy Mar 02 '13 at 21:59
The article are great, your answer however, would be more helpful if it explained this situation more in depth. I find HellBricks answer more helpful, since this was the resolving answer for my problem. – Christopher Bonitz Jan 21 '16 at 14:47

score 13 · Answer 2 · answered Apr 15 '14 at 08:04

If you need this behavior for all the properties of all the classes you're going to send (which is exactly the case that has led me to this question), I think this would be cleaner:

using ( HttpClient http = new HttpClient() )
{
    var formatter = new JsonMediaTypeFormatter();
    formatter.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;

    TestDocument value = new TestDocument();
    HttpContent content = new ObjectContent<TestDocument>( value, formatter );
    await http.PutAsync( url, content );
}

This way there's no need to add attributes to your classes, and you still don't have to serialize all the values manually.

score 7 · Answer 3 · answered May 30 '14 at 01:42

use HttpClient.PostAsync

JsonMediaTypeFormatter jsonFormat = new JsonMediaTypeFormatter();
jsonFormat.SerializerSettings.DefaultValueHandling = Newtonsoft.Json.DefaultValueHandling.Ignore;
jsonFormat.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;

HttpResponseMessage res = c.PostAsync<T>(url, TObj, jsonFormat).Result;

Steven V · Answer 4 · 2013-03-02T22:28:13.570

3

I'm not sure you can do that with the PutAsJsonAsync as you have it right now. Json.NET can do this though, if you're able to use it, and a NuGet package exists if it helps. If you can use it, I'd rewrite the InsertDocument function to look like:

public static HttpResponseMessage InsertDocument(object doc, string name, string db)
    {
      HttpResponseMessage result;
      string json = JsonConvert.SerializeObject(doc, Formatting.Indented, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore });
      if (String.IsNullOrWhiteSpace(name)) result = clientSetup().PostAsync(db, new StringContent(json, null, "application/json")).Result;
      else result = clientSetup().PutAsync(db + String.Format("/{0}", name), new StringContent(json, null, "application/json")).Result;
      return result;
    }

edited Mar 02 '13 at 22:28

answered Mar 02 '13 at 20:44

Steven V

16,357
3
63
76

clientSetup().PostAsync(db, new StringContent(json, null, "application/json")).Result; – James Mundy Mar 02 '13 at 21:46
I used that to get it working but (as I mentioned above) it is still ignoring this for both methods and sending the null variables – James Mundy Mar 02 '13 at 21:47
This works but unfortunately I'm going to mark the above as the right answer as it involves the least changes to my code. – James Mundy Mar 02 '13 at 22:00
@JamesMundy Wow. Didn't even know about the attribute. I'll be using that from now on! Good call. – Steven V Mar 02 '13 at 22:28

How to get HttpClient Json serializer to ignore null values

4 Answers4