区分大小写的建议-Elasticsearch短语建议者

Question

如何不区分大小写地搜索，但基于原始索引文档返回建议？

例如：搜索“ 贵族奖”，然后建议“ 诺贝尔奖”。

---

完整示例：

创建索引：

PUT test
{
  "settings": {
    "index": {
      "number_of_shards": 1,
      "analysis": {
        "analyzer": {
          "trigram": {
            "type": "custom",
            "tokenizer": "standard",
            "filter": ["standard", "shingle"]
          }
        },
        "filter": {
          "shingle": {
            "type": "shingle",
            "min_shingle_size": 2,
            "max_shingle_size": 3
          }
        }
      }
    }
  },
  "mappings": {
    "test": {
      "properties": {
        "title": {
          "type": "text",
          "fields": {
            "trigram": {
              "type": "text",
              "analyzer": "trigram"
            }
          }
        }
      }
    }
  }
}

索引文件：

POST test/test?refresh=true
{"title": "Nobel Prize"}

搜索：

POST test/_search
{
  "suggest": {
    "text": "noble prize",
    "simple_phrase": {
      "phrase": {
        "field": "title.trigram",
        "size": 1,
        "gram_size": 3,
        "direct_generator": [ {
          "field": "title.trigram",
          "suggest_mode": "always"
        } ],
        "highlight": {
          "pre_tag": "<em>",
          "post_tag": "</em>"
        }
      }
    }
  }
}

但是不会返回simple_phrase建议。 我希望它返回“诺贝尔奖”（区分大小写）：

{
  "suggest": {
    "simple_phrase": [
      {
        "text": "noble prize",
        "offset": 0,
        "length": 11,
        "options": [
          {
            "text": "Nobel Prize",
            "highlighted": "<em>Nobel</em> Prize",
            "score": 0.5508418
          }
        ]
      }
    ]
  }
}