elasticsearch case insensitive term filter search on not_analyzed field

Question

There are similar questions asked here Elasticsearch Map case insensitive to not_analyzed documents, however mine is a slightly different because I deal with special characters.

Most people recommend using a keyword analyzer combined with lowercase filter. However, this does not work for my case because keyword analyzer tokenizes on spaces, and special characters like ^, #, etc. which break the type of support I'm going for.

i.e.

1. ^HELLOWORLD should be matched by searching ^helloworld, but not helloworld
2. #FooBar should be matched by #foobar but not foobar.
3. Foo Bar should be matched by foo bar, but not foo or bar.

Similar functionality with what we see here https://www.elastic.co/guide/en/elasticsearch/guide/current/_finding_exact_values.html#_term_filter_with_numbers, but with case insensitivity.

Does anyone know how to accomplish this?

EDIT 1:

It seems the core of my problem was with multi-field, as keyword+lowercase seems to resolve the question posed in the title. However, it would be more accurate to pose this question for a multi-field value property.

test_mapping.json:

{
  "properties" : {
    "productID1" : {
      "type" : "string",
      "index_analyzer" :  "keyword_lowercase",
      "search_analyzer" : "keyword_lowercase"
    },
    "productID2" : {
      "type": "multi_field",
      "keyword_edge_ID": {
        "type": "string", 
        "index_analyzer":"keyword_lowercase_edge", 
        "search_analyzer":"keyword_lowercase_edge"
      },
      "productID2": {
        "type": "string", 
        "index": "analyzed", 
        "store": "yes", 
        "index_analyzer":"keyword_lowercase", 
        "search_analyzer":"keyword_lowercase"
      }
    }
  }
}

test.json:

{
  "index": {
    "analysis": {
      "filter":{
        "edgengramfilter": {
          "type": "edgeNgram",
          "side": "front",
          "min_gram": 1,
          "max_gram": 32
        }
      },
      "analyzer": {
        "keyword_lowercase" : {
          "type" : "custom",
          "tokenizer": "keyword",
          "filter": "lowercase"
        },
        "keyword_lowercase_edge": {
            "tokenizer": "keyword",
            "filter": ["lowercase", "edgengramfilter"]
        }
      }
    }
  }
}

Shell script to create index with mappings:

#!/bin/sh

ES_URL="http://localhost:9200"

curl -XDELETE $ES_URL/test
curl -XPOST $ES_URL/test/ --data-binary @test.json
curl -XPOST $ES_URL/test/query/_mapping --data-binary @test_mapping.json

POST localhost:9200/test/query:

{ 
  "productID1" : "^A",
  "productID2" : "^A" 
}

I'd like it so that I can match against productID2 with "^A", but it is returning no results right now, but it works when I do the same query against productID1. {"query": { "match": { "productID2": "^A" }}}

Answer 1

As you can see in the example below, the keyword tokenizer and lowercase filter is doing exactly that - it lowercases the entire value while preserving all spaces and special characters. The example of how to use it can be found in this answer.

curl "localhost:9200/_analyze?pretty&tokenizer=keyword&filters=lowercase" -d "^HELLOWORLD"
{
  "tokens" : [ {
    "token" : "^helloworld",
    "start_offset" : 0,
    "end_offset" : 11,
    "type" : "word",
    "position" : 1
  } ]
}

curl "localhost:9200/_analyze?pretty&tokenizer=keyword&filters=lowercase" -d "#FooBar"    
{
  "tokens" : [ {
    "token" : "#foobar",
    "start_offset" : 0,
    "end_offset" : 7,
    "type" : "word",
    "position" : 1
  } ]
}

curl "localhost:9200/_analyze?pretty&tokenizer=keyword&filters=lowercase" -d "Foo Bar"
{
  "tokens" : [ {
    "token" : "foo bar",
    "start_offset" : 0,
    "end_offset" : 7,
    "type" : "word",
    "position" : 1
  } ]
}