如何使用NEST准确表示此ElasticSearch查询？

Question

Background / Goal

I have a query in ElasticSearch where I'm using filters on a several fields (relatively small data set and we know exactly what values should be in those fields at the time we query). The idea is that we'll perform a full-text query but only after we've filtered on some selections as made by the user.

I'm putting ElasticSearch behind a WebAPI controller and figured it made sense to use NEST to accomplish the query.

The query, in plain English

We have filters for several fields. Each inner filter is an or filter, but they're together as an AND.

In SQL, the pseudo-code equivalent would be select * from table where foo in (1,2,3) AND bar in (4,5,6) .

Questions

• Can I simplify the way I'm thinking about this query, based on what you see below? Am I overlooking some basic approach? This seems heavy but I'm new to ES.
• How would I properly represent the query below in NEST syntax?
• Is NEST the best choice for this? Should I be using the ElasticSearch library instead and going lower level?

The Query Text

{
  "query": {
    "filtered": {
      "filter": {
        "bool": {
          "must": [
            {
              "or": [
                { "term": { "foo": "something" } },
                { "term": { "foo": "somethingElse" } }
              ]
            },
            {
              "or": [
                { "term": { "bar": "something" } },
                { "term": { "bar": "somethingElse" } }
              ]
            }
          ]
        }
      }
    }
  },

  "size": 100
}

Answer 1

This kind of task is quite simple and popular in ES. You can represent it in NEST like following:

var rs = es.Search<dynamic>(s => s
            .Index("your_index").Type("your_type")
            .From(0).Size(100)
            .Query(q => q
                .Filtered(fq => fq
                    .Filter(ff => ff
                        .Bool(b => b
                            .Must(
                                m1 => m1.Terms("foo", new string[] { "something", "somethingElse" }),
                                m2 => m2.Terms("bar", new string[] { "something", "somethingElse" })
                            )
                        )
                    )
                    .Query(qq => qq
                        .MatchAll()
                    )
                )
            )
        );

Some notes:

• I use filtered query to filter what I need first, then search stuffs later. In this case the it will filter for foo in ("something", "somethingElse") AND bar in ("something", "somethingElse") , then query all filtered results ( match_all ). You can change match_all to what you need. filtered query it's for best performance as ES will only need to evaluate scores of documents in query part (after filtered), not all documents.
• I use terms filter, which more simple and better performance than or . Default mode of terms is OR all input terms, you can refer more in document about available modes (AND, OR, PLAIN, ...).

Nest is best choice for .NET in my opinion as it designed for simple & easy to use purposes. I only used lower API if I want to use new features that Nest does not support at that time, or if Nest have bugs in functions I use. You can refer here for a brief NEST tutorial: http://nest.azurewebsites.net/nest/writing-queries.html

Updated: Building bool filters dynamic:

var filters = new List<Nest.FilterContainer>();
filters.Add(Nest.Filter<dynamic>.Terms("foo", new string[] { "something", "somethingElse" }));
// ... more filter

then replace .Bool(b => b.Must(...)) with .Bool(b => b.Must(filters.ToArray()))

Hope it help