ElasticSearch C＃NEST-scriptscorefunction不起作用

Question

I'm trying to write a script score function which boosts items who belong to just one category.

                    new ScriptScoreFunction
                    {
                        Script = new ScriptQuery
                        {
                            Lang = "painless",
                            Source = "doc['categories'].values.length == 1",
                        },
                        Weight = 10
                    }

The code below does not seem to work. I'm getting a "bad response code" from the API. What am I doing wrong?

Answer 1

solved by using this as the source of my script:

if (doc['categories.slug'].values.length == 1) { return 1; } return 0;

NOTE: 'slug' is a property of the property 'category'.