How to set field to null in Elasticsearch using C# NEST script?-CodePudding

For example we have following document in elastic:

{
  "name": "Bob",
  "age": "22",
  "phrase": "ohohoho",
  "date": "2022-10-20T00:00:00Z"
}

string phrase ;

DateTime? date;

Then we want put following:

{
  "name": "not Bob",
  "age": "22",
  "phrase": null,
  "date": null
}

in c#:

 var updateRequest = new UpdateRequest<T, T>(entity)
            {
                ScriptedUpsert = true,
                Script = new InlineScript(
                    $"if (someCondition) {{ctx._source.putAll(params.entity);}} else {{ctx.op = \"noop\";}}")
                {
                    Lang = "painless",
                    Params = new Dictionary<string, object>() { { "entity", entity } },
                },
                Upsert = Activator.CreateInstance<T>()
            };

but in the end it will not update phrase and date. It makes following request:


POST /myIndex/_update/b90278fd-1a66-40bf-b775-d076122c6c02
{
    "script": {
        "source": ""if (someCondition) {{ctx._source.putAll(params.entity);}} else {{ctx.op = \"noop\";}}"",
        "lang": "painless",
        "params": { 
          "entity": {
               "name": "",
               "age": 22
            }
        }
    },
    "upsert": {
        "age": 0
    }
}

Idk why but it skips all fields with null. How to update nullable fields to null?

CodePudding user response：

NEST does not support sending null values by default.

You can have a check in script such that if a value is not passed then you can remove it from document.

var updateRequest = new UpdateRequest<T, T(entity)
            {
                ScriptedUpsert = true,
                Script = new InlineScript($"if (params.entity.phrase==null)ctx._source.remove('phrase');")
                {
                    Lang = "painless",
                    Params = new Dictionary<string, object>() { { "entity", entity } },
                },
                Upsert = Activator.CreateInstance<T>()
            };

You can check for more details here