elasticsearch返回指定字段

1. postman 请求elasticsearch 返回指定字段

　　1.直接在请求体当中，json 数据，对应的是一个列表

{

　　"_source":['title','id','desc'],
　　"from":10,
　　"size":100,

}

　　　至于from和size是浅分页

 　　　2. 或者这样

{
    "_source":{
        "includes":["title","url","id"],
        "excludes":["desc"]
    }
}

　　其中includes代表需要返回的字段，excludes代表不要返回的字段

　　3.直接在请求url带上需要查询参数

curl -XGET 'localhost:9200/_search?pretty&filter_path=took,hits.hits._id,hits.hits._score'

{
  "took" : 3,
  "hits" : {
    "hits" : [
      {
        "_id" : "3640",
        "_score" : 1.0
      },
      {
        "_id" : "3642",
        "_score" : 1.0
      }
    ]
  }
}

　　对_source的字段进行过滤

curl -XGET 'localhost:9200/_search?pretty&filter_path=hits.hits._source&_source=title'

{
  "hits" : {
    "hits" : [ {
      "_source":{"title":"Book #2"}
    }, {
      "_source":{"title":"Book #1"}
    }, {
      "_source":{"title":"Book #3"}
    } ]
  }
}

 　　这样也可以

_search?_source=goodsId,uri

_search?fields=goodsId,uri

2.python 对接elassearch ，指定返回字段

　　1.实例化的es客户端，然后调用search方法，传入参数，params

from elasticsearch import Elasticsearch

es=Elasticseach(xxxx) es.search(params={"_source":"title,id,desc,url"})

 　　注：这边调用的是包中的search方法，和postman不一样的是，_source的值是一个z字符串，不同字段用逗号隔开，而post满是一个列表

 　　2.也是调用Elasticsearch的search方法，传入参数不是param，而直接是_source字段

pprint(es.search(index='person', body={"query": {"match": {"age": "19"}}}, _source=['name']))

　　结果：

{'_shards': {'failed': 0, 'skipped': 0, 'successful': 1, 'total': 1},
 'hits': {'hits': [{'_id': 'xFznIXIBMTX0DMkCyicV',
                    '_index': 'person',
                    '_score': 1.0,
                    '_source': {'name': 'lisi'},
                    '_type': 'male'}],
          'max_score': 1.0,
          'total': {'relation': 'eq', 'value': 1}},
 'timed_out': False,
 'took': 1}

3.不懂直接查询api接口

　　https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-get.html

4.返回文档版本字段

GET /_search
{
    "version": true,
    "query" : {
        "term" : { "user" : "kimchy" }
    }
}

5.Script Field 用脚本来对命中的每个文档的字段进行运算后返回

GET /bank/_search
{
  "query": {
    "match_all": {}
  },
  "script_fields": {
    "test1": {
      "script": {
        "lang": "painless",
        "source": "doc['balance'].value * 2"
      }
    },
    "test2": {
      "script": {
        "lang": "painless",
        <!--  doc指文档-->
        "source": "doc['age'].value * params.factor",
        "params": {
          "factor": 2
        }
      }
    } }}

　　搜索结果：

{
  "took": 3,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 1000,
    "max_score": 1,
    "hits": [
      {
        "_index": "bank",
        "_type": "_doc",
        "_id": "25",
        "_score": 1,
        "fields": {
          "test1": [
          ],
          "test2": [
          ]
        }
      },
      {
        "_index": "bank",
        "_type": "_doc",
        "_id": "44",
        "_score": 1,
        "fields": {
          "test1": [
          ],
          "test2": [
          ]
        }
      }
      }
    ]
  }
}

　　示例2

 
GET /bank/_search
{
  "query": {
    "match_all": {}
  },
  "script_fields": {
    "ffx": {
      "script": {
        "lang": "painless",
        "source": "doc['age'].value * doc['balance'].value"
      }
    },
    "balance*2": {
      "script": {
        "lang": "painless",
        "source": "params['_source'].balance*2"
      }
    }
  }
}

　　搜索结果：

{
  "took": 26,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 1000,
    "max_score": 1,
    "hits": [
      {
        "_index": "bank",
        "_type": "_doc",
        "_id": "25",
        "_score": 1,
        "fields": {
          "balance*2": [
          ],
          "ffx": [
          ]
        }
      },
      {
        "_index": "bank",
        "_type": "_doc",
        "_id": "44",
        "_score": 1,
        "fields": {
          "balance*2": [
          ],
          "ffx": [
          ]
        }
      },

      }
    ]
  }
}

　　

　　说明： params  _source 取 _source字段值

　　官方推荐使用doc，理由是用doc效率比取_source 高

参考：https://zyc88.blog.csdn.net/article/details/91463409