排除elasticsearch结果数据中的_id和_index字段

如果简单地点击 api，每个文档中有 5 个字段。但我只想要这两个字段（user_id 和 loc_code），所以我在字段列表中提到。但它仍然返回一些不必要的数据，如_shards、hits、time_out等。

使用下面的查询在 chrome 中的 postman 插件中发出 POST 请求

<:9200>/myindex/mytype/_search
{
    "fields" : ["user_id", "loc_code"],
    "query":{"term":{"group_id":"1sd323s"}}
}   

// 输出

 {
        "took": 17,
        "timed_out": false,
        "_shards": {
            "total": 5,
            "successful": 5,
            "failed": 0
        },
        "hits": {
            "total": 323,
            "max_score": 8.402096,
            "hits": [
                {
                    "_index": "myindex",
                    "_type": "mytype",
                    "_id": "<someid>",
                    "_score": 8.402096,
                    "fields": {
                        "user_id": [
                            "<someuserid>"
                        ],
                        "loc_code": [
                            768
                        ]
                    }
                },
               ...
            ]
        }
    }

但我只想要文档字段（提到的两个字段），我也不想要 _id、_index、_type。有什么办法可以做到吗

一个可能不完整但有很大帮助的解决方案是使用filter_path https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#common-options-response-filtering。例如，假设我们的索引中有以下内容：

PUT foods/_doc/_bulk
{ "index" : { "_id" : "1" } }
{ "name" : "chocolate cake", "calories": "too much" }
{ "index" : { "_id" : "2" } }
{ "name" : "lemon pie", "calories": "a lot!"  }
{ "index" : { "_id" : "3" } }
{ "name" : "pizza", "calories": "oh boy..."  }

像这样的搜索...

GET foods/_search
{
  "query": {
    "match_all": {}
  }
}

...将产生大量元数据：

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 3,
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "foods",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "name" : "lemon pie",
          "calories" : "a lot!"
        }
      },
      {
        "_index" : "foods",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "chocolate cake",
          "calories" : "too much"
        }
      },
      {
        "_index" : "foods",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 1.0,
        "_source" : {
          "name" : "pizza",
          "calories" : "oh boy..."
        }
      }
    ]
  }
}

但是如果我们给搜索 URL 参数filter_path=hits.hits._source...

GET foods/_search?filter_path=hits.hits._source
{
  "query": {
    "match_all": {}
  }
}

...它只会返回源（尽管仍然嵌套得很深）：

{
  "hits" : {
    "hits" : [
      {
        "_source" : {
          "name" : "lemon pie",
          "calories" : "a lot!"
        }
      },
      {
        "_source" : {
          "name" : "chocolate cake",
          "calories" : "too much"
        }
      },
      {
        "_source" : {
          "name" : "pizza",
          "calories" : "oh boy..."
        }
      }
    ]
  }
}

您甚至可以过滤字段：

GET foods/_search?filter_path=hits.hits._source.name
{
  "query": {
    "match_all": {}
  }
}

...你会得到这个：

{
  "hits" : {
    "hits" : [
      {
        "_source" : {
          "name" : "lemon pie"
        }
      },
      {
        "_source" : {
          "name" : "chocolate cake"
        }
      },
      {
        "_source" : {
          "name" : "pizza"
        }
      }
    ]
  }
}

如果您愿意，您还可以做更多事情：只需检查文档 https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#common-options-response-filtering.